The main elements of the joint and their functions. The structure and types of joints

The human skeleton consists of more than 200 bones, most of which are movably connected by joints and ligaments. It is thanks to them that a person can move freely and perform various manipulations. In general, all joints are arranged in the same way. They differ only in form, the nature of movement and the number of articulating bones.

Joints simple and complex

Classification of joints anatomical device

According to their anatomical structure, the joints are divided into:

Simple. The joint is made up of two bones. An example is the shoulder or interphalangeal joints.
Complex. A joint is made up of 3 or more bones. An example is the elbow joint.
Combined. Physiologically, the two joints exist separately, but function only as a pair. Thus, the temporomandibular joints are arranged (it is impossible to lower only the left or right part of the jaw, both joints work simultaneously). Another example is the symmetrically located facet joints of the spinal column. The structure of the human spine is such that movement in one of them entails displacement of the other. To understand the principle of work more precisely, read an article with beautiful illustrations about the structure of the human spine.
Complex. The joint gap is divided into two cavities by cartilage or meniscus. An example is the knee joint.

Classification of joints by shape

The shape of the joint can be:

Cylindrical. One of the articular surfaces looks like a cylinder. The other has an appropriately sized recess. The radioulnar joint belongs to the cylindrical joints.
Blocky. The head of the joint is the same cylinder, on the lower side of which a ridge is placed perpendicular to the axis. On the other bone there is a depression - a groove. The comb fits into the groove like a key to a lock. This is how the ankle joints are arranged.
A special case of block-shaped joints is a helical joint. Its distinctive feature lies in the spiral arrangement of the groove. An example is the shoulder joint.
Ellipsoid. One articular surface has an ovoid bulge, the second has an oval notch. These are the metacarpophalangeal joints. When the metacarpal cavities rotate relative to the phalangeal bones, complete bodies of rotation are formed - ellipses.
Myshchelkov. It is similar in structure to the ellipsoid, but its articular head is located on a bony protrusion - the condyle. An example is the knee joint.

saddle. In its form, the joint is similar to two saddles nested in each other, the axes of which intersect at right angles. The carpometacarpal joint of the thumb belongs to the saddle, which among all mammals is found only in humans.
spherical. The joint articulates the spherical head of one bone and the cup-shaped recess of the other. The representative of this type of joints is the hip joint. When the cavity of the pelvic bone rotates relative to the head of the femur, a ball is formed.
Flat. The articular surfaces of the joint are flattened, the range of motion is negligible. The flat ones include the lateral atlanto-axial joint, which connects the 1st and 2nd cervical vertebrae, or the lumbosacral joints.
Changing the shape of the joint leads to dysfunction of the musculoskeletal system and the development of pathologies. For example, against the background of osteochondrosis, the articular surfaces of the vertebrae are displaced relative to each other. This condition is called spondylarthrosis. Over time, the deformation is fixed and develops into a persistent curvature of the spine. Instrumental methods of examination (computed tomography, radiography, MRI of the spine) help to detect the disease.

Division according to the nature of the movement

The movement of the bones in the joint can occur around three axes - sagittal, vertical and transverse. All of them are mutually perpendicular. The sagittal axis is located in the direction from front to back, the vertical axis is from top to bottom, the transverse axis is parallel to the arms extended to the sides.
According to the number of axes of rotation, the joints are divided into:

uniaxial (these include block-shaped),
biaxial (ellipsoid, condylar and saddle),
multiaxial (spherical and flat).

Summary table of movements in the joints

Number of axes Joint shape Examples

One Cylindrical Median antlantoaxial (located between the 1st and 2nd cervical vertebrae)

One Blocky Elbow

Two Ellipsoidal Atlantococcipital (connects the base of the skull to the upper cervical vertebrae)

Two Condylar Knee

Two saddle carpometacarpal thumb

Three Ball Shoulder

Three flat facet joints (included in all parts of the spine)

Classification of types of movements in the joints:

Movement around the frontal (horizontal) axis - flexion (flexio), i.e., a decrease in the angle between the articulating bones, and extension (extensio), i.e., an increase in this angle.
Movements around the sagittal (horizontal) axis are adduction (adductio), i.e., approaching the median plane, and abduction (abductio), i.e., moving away from it.
Movements around the vertical axis, i.e. rotation (rotatio): inwards (pronatio) and outwards (supinatio).
A circular motion (circumductio) in which a transition is made from one axis to another, with one end of the bone describing a circle, and the entire bone a cone figure.

An introductory list of the most common diseases:

arthritis: rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, gout on the legs ... according to WHO, there are about 100 different forms of this disease)
arthrosis
bursitis

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Structure

In the structure of any articular joint, the main articular components are distinguished: the articular surface of the epiphysis of the bone, synovial fluid, synovial cavity, synovial membrane, composite bag. In addition, there is a meniscus in the structure of the knee (it is a cartilaginous formation that optimizes the conformity of the articular surfaces and is a shock absorber).

The articular surface of any bone is covered with hyaline cartilage, sometimes fibrous. The thickness of hyaline cartilage is about half a millimeter. The smoothness of hyaline cartilage is ensured by constant friction. Cartilage has elastic properties and therefore performs a buffering function.

The joint capsule or capsule is attached to the bones near the edges of the articular surfaces. Its function is to protect against damage (usually ruptures and mechanical damage), in addition, the inner synovial membrane performs the function of synovial fluid secretion. Outside, the bag is covered with a fibrous membrane, and inside it is lined with a synovial membrane. The outer layer is stronger and thicker than the inner layer, the fibers are directed longitudinally.

As for the synovial cavity, it is a closed, airtight, gap-like space that limits the articular surfaces of the bones and the synovial membrane. If we consider the knee, then in the synovial cavity is the meniscus.

Additional articular components are muscles and tendons, ligaments, nerves and blood vessels, which indirectly surround the joint, provide its nutrition and innervation. They are also called joint tissues. These fabrics provide mobility and perform a strengthening function. It is through them that the vessels of the microcirculatory bed pass, which feed the joint, and thin "branches" of nerves that directly innervate it.

Currently, all joints are classified by the number of surfaces, by function and by the shape of the articular surface.

1. By the number of surfaces:

1.1. Simple joint. It consists of two surfaces. An example is the interphalangeal joint.

1.2. Difficult. It consists of three or more surfaces. An example is the elbow joint.

1.3. Complex. It consists of cartilage, which divides the articulation into two chambers. An example is the temporomandibular joint.

1.4. Combined. It consists of several isolated joints. An example is the temporomandibular joint.

2. According to their function and form, they are divided into:

2.1. with one axle.

2.1.1. In the form of a cylinder. An example is the atlanto-axial articulation of the spine.

2.1.2. Blocky (blocky). An example is the interphalangeal joints.

2.1.3. In the form of a screw. An example is the shoulder joint.

2.2. with two axles.

2.2.1. In the form of an ellipse. An example is the wrist joint.

2.2.2. Condylar. An example of such a joint is the knee.

2.2.3. In the form of a saddle. An example is the carpometacarpal joint for the first toe.

2.3. having more than two axles.

2.3.1. In the form of a ball. An example is the shoulder.

2.3.2. In the form of a bowl. An example is the hip joint.

2.3.3. Flat. An example is the intervertebral joint.

Before talking about these diseases, I want to say right away that they are a severe pathology. Only qualified specialists should treat it! Self-medication in this case is strictly contraindicated, because it can only aggravate the course of an already severe and slowly ongoing disease.

As for joint diseases, there are quite a lot of them now. Below are the most frequently encountered.

Some diseases

hypermobility

Increased mobility, or - the second name - hypermobility of the joint, is characterized by congenital sprain, which makes it possible to perform movements that go beyond the average limits. As a result of such a movement, a characteristic click can be heard (it should immediately be noted that this click can be a symptom of other conditions, for example, excessive salt deposition in metabolic disorders).

The reason for the excessive extensibility of the ligaments are violations in the structure of collagen fibers, as a result, the strength of collagen decreases, and, accordingly, it becomes more elastic and more prone to stretching. Scientists have established the hereditary nature of the transmission of this condition, but the mechanism of development has not been fully studied.

Increased mobility is most often detected in young women.

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Anatomical features

Human joints are the basis of every movement of the body. They are found in all bones of the body (the only exception is the hyoid bone). Their structure resembles a hinge, due to which the bones slide smoothly, preventing their friction and destruction. A joint is a movable connection of several bones, and in the body there are more than 180 of them in all parts of the body. They are fixed, partially movable, and the main part is represented by movable joints.

The degree of mobility depends on the following conditions:

volume of connecting material;
type of material inside the bag;
the shape of the bones at the point of contact;
the level of muscle tension, as well as ligaments inside the joint;
their location in the bag.

How is the joint arranged? It looks like a bag of two layers that surrounds the connection of several bones. The bag ensures the tightness of the cavity and promotes the production of synovial fluid. She, in turn, is a shock absorber of bone movements. Together they perform three main functions of the joints: they contribute to the stabilization of the body position, they are part of the process of movement in space, and they ensure the movement of parts of the body in relation to each other.

The main elements of the joint

The structure of human joints is not simple and is divided into such basic elements: a cavity, a capsule, a surface, synovial fluid, cartilage, ligaments and muscles. Let's briefly talk about each below.

The articular cavity is a slit-like space, which is hermetically sealed and filled with synovial fluid.
Joint capsule - consists of connective tissue that envelops the connecting ends of the bones. The capsule is formed on the outside of a fibrous membrane, while inside it has a thin synovial membrane (the source of synovial fluid).
Articular surfaces - have a special shape, one of them is convex (also called the head), and the second is pit-like.

synovial fluid. Its main function is to lubricate and moisten surfaces, it also plays an important role in fluid exchange. It is a buffer zone for various movements (shocks, jerks, squeezing). Provides both sliding and divergence of bones in the cavity. Reducing the number of synovia leads to a number of diseases, bone deformities, loss of a person's ability to normal physical activity and, as a result, even to disability.
Cartilaginous tissue (thickness 0.2 - 0.5 mm). The surfaces of the bones are covered with cartilaginous tissue, the main function of which is cushioning during walking, playing sports. Cartilage anatomy is represented by connective tissue fibers that are filled with fluid. It, in turn, nourishes the cartilage in a calm state, and during movement, it releases a fluid to lubricate the bones.
Ligaments and muscles are auxiliary parts of the structure, but without them the normal functionality of the whole organism is impossible. With the help of ligaments, bones are fixed, without interfering with movements of any amplitude due to their elasticity.

The oblique protrusions around the joints also play an important role. Their main function is to limit the range of motion. As an example, consider the shoulder. There is a bony tubercle in the humerus. Due to its location near the process of the scapula, it reduces the range of motion of the hand.

Classification and types

In the process of development of the human body, the way of life, the mechanisms of interaction between a person and the external environment, the need to perform various physical actions, various types of joints were obtained. The classification of joints and its main principles are divided into three groups: the number of surfaces, the shape of the end of the bones, and functionality. We will talk about them a little later.

The main type in the human body is the synovial joint. Its main feature is the connection of bones in a bag. This type includes shoulder, knee, hip and others. There is also the so-called facet joint. Its main feature is a 5-degree swivel and 12-degree tilt limit. The function also consists in limiting the mobility of the spine, which allows you to maintain the balance of the human body.

By structure

In this group, the classification of joints occurs depending on the number of bones that connect:

A simple joint is the connection of two bones (interphalangeal).
Complex - the connection of more than two bones (elbow). The characteristic of such a connection implies the presence of several simple bones, while the functions can be implemented separately from each other.
A complex joint - or a two-chamber joint, which contains cartilage that connects several simple joints (mandible, radioulnar). Cartilage can separate joints either completely (disc shape) or partially (meniscus in the knee).
Combined - combines isolated joints that are placed independently of each other.

According to the shape of the surfaces

The forms of the joints and the ends of the bones have the forms of various geometric shapes (cylinder, ellipse, ball). Depending on this, movements are carried out around one, two, or three axes. There is also a direct relationship between the type of rotation and the shape of the surfaces. Further, a detailed classification of the joints according to the shape of its surfaces:

Cylindrical joint - the surface has the shape of a cylinder, rotates around one vertical axis (parallel to the axis of the connected bones and the vertical axis of the body). This species may have a rotational name.
Block joint - inherent in the shape of a cylinder (transverse), one axis of rotation, but in the frontal plane, perpendicular to the connected bones. Features flexion and extension movements.
Helical - a variation of the previous type, but the rotation axes of this form are located at an angle other than 90 degrees, forming helical rotations.
Ellipsoid - the ends of the bones have the shape of an ellipse, one of them is oval, convex, the second is concave. Movements occur in the direction of two axes: bend-unbend, withdraw-bring. The ligaments are perpendicular to the axes of rotation.
Condylar - a kind of ellipsoid. The main characteristic is the condyle (a rounded process on one of the bones), the second bone is in the form of a cavity, which can differ significantly in size from each other. The main axis of rotation is represented by the frontal one. The main difference from block-shaped is a strong difference in the size of the surfaces, from ellipsoid - by the number of heads of connecting bones. This type has two condyles, which can be located either in the same capsule (similar to a cylinder, similar in function to block-shaped), or in different ones (similar to ellipsoidal).

Saddle-shaped - is formed by connecting two surfaces, as it were, "sitting" on top of each other. One bone moves along, while the second across. Anatomy involves rotation around perpendicular axes: flexion-extension and abduction-adduction.
Spherical joint - the surfaces are in the form of balls (one convex, the second concave), due to which people can make circular movements. Basically, rotation occurs along three perpendicular axes, the point of intersection is the center of the head. A feature in a very small number of ligaments, which does not interfere with circular rotations.
Cup-shaped - the anatomical view suggests a deep cavity of one bone, which covers most of the area of the head of the second surface. As a result, less free mobility compared to spherical. Necessary for a greater degree of stability of the joint.
Flat joint - flat ends of bones of approximately the same size, interaction along three axes, the main characteristic is a small range of motion and surrounded by ligaments.
Tight (amphiarthrosis) - consists of bones of different sizes and shapes, which are closely connected to each other. Anatomy - sedentary, surfaces are represented by tight capsules, not elastic short ligaments.

According to the nature of the movement

In view of their physiological characteristics, the joints make many movements along their axes. In total, this group distinguishes three types:

Uniaxial - which rotate around one axis.
Biaxial - rotation around two axes.
Multi-axis - mainly around three axes.

Axis classification	Kinds	Examples
uniaxial	Cylindrical	Atlanto-Axial Median
	blocky	Interphalangeal joints of fingers
	helical	Shoulder-ulnar
biaxial	Ellipsoid	radiocarpal
	Condylar	Knee
	saddle	Carpometacarpal joint of thumb
multi-axle	Globular	Brachial
	bowl-shaped	Hip
	Flat	Intervertebral discs
	Tight	sacroiliac

In addition, there are also different types of movements in the joints:

Flexion and extension.
Rotation in and out.
Withdrawal and adduction.
Circular movements (surfaces move between axes, the end of the bone writes a circle, and the entire surface forms a cone shape).
Sliding movements.
Removing one from the other (example, peripheral joints, distance of fingers).

The degree of mobility depends on the difference in the size of the surfaces: the greater the area of one bone above the other, the greater the amount of movement. Ligaments and muscles can also slow down the range of motion. Their presence in each type is determined by the need to increase or decrease the range of motion of a certain part of the body.

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shoulder joint

It is the most mobile in humans and is formed by the head of the humerus and the glenoid cavity of the scapula.

The articular surface of the scapula is surrounded by a ring of fibrous cartilage - the so-called articular lip. The tendon of the long head of the biceps brachii passes through the joint cavity. The shoulder joint is strengthened by a powerful coraco-shoulder ligament and the surrounding muscles - deltoid, subscapular, supra- and infraspinatus, large and small round. The pectoralis major and latissimus dorsi muscles also take part in the movements of the shoulder.

The synovial membrane of the thin articular capsule forms 2 extra-articular torsion - the tendons of the biceps of the shoulder and the subscapularis. The anterior and posterior arteries enveloping the humerus and the thoracoacromial artery take part in the blood supply of this joint, the venous outflow is carried out into the axillary vein. The outflow of lymph occurs in the lymph nodes of the armpit. The shoulder joint is innervated by branches of the axillary nerve.

In the shoulder joint, movements around 3 axes are possible. Flexion is limited by the acromial and coracoid processes of the scapula, as well as the coracobrachial ligament, extension by the acromion, coracobrachial ligament, and joint capsule. Abduction in the joint is possible up to 90°, and with the participation of the girdle of the upper extremities (with the inclusion of the sternoclavicular joint) - up to 180°. The abduction stops at the moment the large tubercle of the humerus abuts against the coracoid-acromial ligament. The spherical shape of the articular surface allows a person to raise the arm, take it back, rotate the shoulder together with the forearm, the hand in and out. This variety of hand movements was a decisive step in the process of human evolution. The shoulder girdle and shoulder joint in most cases function as a single functional entity.

hip joint

It is the most powerful and heavily loaded joint in the human body and is formed by the acetabulum of the pelvic bone and the head of the femur. The hip joint is strengthened by the intra-articular ligament of the head of the femoral brush, as well as the transverse ligament acetabulum, covering the neck of the femur. Outside, a powerful ilio-femoral, pubic-femoral and ischio-femoral ligaments are woven into the capsule.

The blood supply to this joint is carried out through the arteries that envelop the femur, branches of the obturator and (inconsistently) branches of the superior perforating, gluteal and internal pudendal arteries. The outflow of blood occurs through the veins surrounding the femur, into the femoral vein and through the obturator veins into the iliac vein. Lymph drainage is carried out to the lymph nodes located around the external and internal iliac vessels. The hip joint is innervated by the femoral, obturator, sciatic, superior and inferior gluteal, and pudendal nerves.
The hip joint is a type of ball-and-socket joint. It allows movement around the frontal axis (flexion and extension), around the sagittal axis (abduction and adduction) and around the vertical axis (external and internal rotation).

This joint is under heavy load, so it is not surprising that its lesions occupy the first place in the general pathology of the articular apparatus.

Knee-joint

One of the largest and most complex human joints. It is made up of 3 bones: the femur, tibia, and fibula. Stability of the knee joint is provided by intra- and extra-articular ligaments. The extra-articular ligaments of the joint are the peroneal and tibial collateral ligaments, the oblique and arcuate popliteal ligaments, the patellar ligament, and the medial and lateral patella ligaments. The intraarticular ligaments include the anterior and posterior cruciate ligaments.

The joint has many auxiliary elements, such as menisci, intra-articular ligaments, synovial folds, synovial bags. Each knee joint has two menisci, one external and one internal. The menisci have the form of crescents and perform a shock-absorbing role. The auxiliary elements of this joint include synovial folds, which are formed by the synovial membrane of the capsule. The knee joint also has several synovial bags, some of which communicate with the joint cavity.

Everyone had to admire the performances of gymnasts and circus performers. People who can climb into small boxes and bend unnaturally are said to have gutta-percha joints. Of course, this is not so. The authors of The Oxford Handbook of Body Organs assure readers that "in such people the joints are phenomenally flexible" - in medicine this is called joint hypermobility syndrome.

The shape of the joint is a condylar joint. It allows movements around 2 axes: frontal and vertical (with a bent position in the joint). Flexion and extension occur around the frontal axis, and rotation occurs around the vertical axis.

The knee joint is very important for human movement. With each step, by bending, it allows the foot to step forward without hitting the ground. Otherwise, the leg would be brought forward by raising the hip.

According to the World Health Organization, every 7th inhabitant of the planet suffers from joint pain. Between the ages of 40 and 70, joint disease occurs in 50% of people and in 90% of people over 70 years of age.
According to www.rusmedserver.ru, meddoc.com.ua

7 early signs of arthritis

8 ways to ruin your knees

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Simple and complex joints

A simple joint got its name, as you might guess, because of the simplicity of the design. The main elements of the joint form the surfaces of two bones. To make it easier to understand where it is, just look at the person’s shoulder. The humerus and the cavity of the scapula are connected by a special tissue. A complex structure will consist of 3 simpler structures that are united by a common capsule. For example, the elbow joint is complex, as it has the surfaces of three bones:

brachial;
elbow;
ray.

Combined joints are often confused by non-specialists in medicine with complex ones, which is quite natural, since these elements are similar to each other. Only complex in its design has a common capsule, while the combined one does not. The second joint differs from the previous ones in that its components are disconnected, but this does not prevent them from functioning together. The right and left temporomandibular joints are classified as combined. The complex joint, in turn, is similar to the combined joint. Sometimes in publications you can find information that they are considered as a single group, which is not true, since these are different elements. The characteristic of the complex joint differs from the combined one and indicates that the former consists of intra-articular cartilage. The last element divides it into two chambers, and the combined joint does not have them.

Geometry plays a special role in anatomy, because many parts of the body get their names because of their similarity with a particular geometric figure. When dividing various forms of human joints into groups, associations of the similarity of body elements with geometric figures were also used. For example, from the name "spherical joint" you can already get an idea of \u200b\u200bits shape. This element is able to move in a circle and is considered the most free. The spherical joint is characterized by increased mobility, thanks to it a person can carry out circular movements.

The spherical nature of this design contributes to the fact that people can rotate, bend and move their limbs along complex trajectories.

Cylindrical, helical, flat joints

A human joint can also have a cylindrical shape. This fastening group is also capable of providing rotational movements of body parts. The cylindrical joint is located in the first and second cervical vertebrae, it is present where the heads of the radius and ulna connect to each other. The cylindrical joint belongs to the category of structures with one axis of motion, if it is damaged, the mobility of the cervical vertebrae is impaired. The trochlear joint looks like a cylinder and belongs to the category of structures with one axis of motion. It is more durable, located in the ankle. Interphalangeal joints are also blocky.

A helical joint is often called a block joint, which is quite natural, since the first is a variation of the second. Both have the same axis of motion. But in the helical guide roller and the recess form a helical direction on its cylindrical surface. The block joint does not have this property. As for the helical analogues, the ulnar one belongs precisely to this category of elements of the human body. Flat structures have a much simpler structure than helical structures, but the former are no less important in the functioning of the body.

The flat design sits on the wrist. It is characterized by the simplest form and a small number of movements. It is called "flat" because it consists of flat surfaces of bones, whose movement is limited by ligaments and bony processes.

One flat joint does not have a significant range of motion, but if a whole group of such elements is involved in the process, the situation changes. Together they are able to carry out complex work, and the range of tasks they perform is significantly increased.

Different surfaces and configurations

The names of the joints have the ability to indicate what parts the biomechanical elements of the body consist of. Joints are intermittent connections of bones, which include cartilage-covered surfaces and capsules.

They have cavities where the synovial fluid is located, a thick, elastic mass washing it. There are not only different forms, but also elements of such structures. Their discs may be in some designs, but not in others. There are varieties that have menisci and special lips. Their surfaces can be different in configuration, their shapes may or may not correspond to each other. But at the same time, without synovial fluid, their tissues are not able to carry out their activities, and their main elements remain the same.

When it comes to the synovial joint, discussion of the treatment of diseases of the musculoskeletal system often begins. Its feature is the bag, where the ends of the bones are located. The synovial fluid is in this sac. Most forms of such structures in the human body are synovial. It is the synovial fluid that prevents the joints from being worn out when they move along the axis of rotation. If the synovial fluid ceases to be renewed in the human body, this means: the pressure in the joint will increase, and it, moving along the axis of rotation, will begin to wear out, like cartilage.

When destructive changes occur in the articular tissue (and they usually develop against a background of impaired metabolism), they are followed by various types of their diseases.

Functions performed by the joints

There is an anatomical classification of joints depending on sections. Not only the characteristics of the constituent parts of each element are taken into account, but also their location on the human body and the functions performed. There are the following types of joints:

movable joints of the ends of the bones of the hand and foot;
elbow;
axillary;
vertebrates;
carpal;
hip;
sternoclavicular;
sacroiliac;
temporomandibular;
knee.

The anatomical table gives a more complete classification (Fig. 1, 2). The functioning of the articular tissue is directly affected by the elements connected by it. For example, the intervertebral joints have limited movement, as there are spinal discs between them. The subtalar joint is located between the talus and calcaneus. Its exact location is their back section. It is considered one of the areas of the body that are significantly prone to dislocations. By the number of dislocations, this element is in 3rd place after dislocations that affect the Lisfranc joint. It is transverse.

The last of them is the tarsal-metatarsal, which, located in the middle part of the foot, has specific anatomical features. The Lisfranc joint does not have a ligament between the bases of the I and II metatarsal bones, it belongs to the category of tarsal-metatarsal analogues and crosses the foot in its middle part. The Lifranc joint belongs to the category of flat analogs and is the most vulnerable point of the body for the occurrence of fractures and dislocations.

To strengthen the Lifranc joint, modern medicine actively uses manual therapy techniques. Nearby, in the area of the foot, there is Chopard's joint. It is considered more durable, this property is due to the peculiarities of its anatomical structure. In cross section, Chopard (tarsi-transverse) resembles the letter S in its shape.

In the foot area, it is strengthened by ligaments, which significantly reduces the level of trauma in this area. It also differs in that it has a common bond.

Mysteries and discoveries of human anatomy

The heel joint is located in the foot area, unique in that it connects three types of bones. It unites not only the calcaneus and navicular bones, but also the one located in the talus. It is a single whole with other tissues located near it. The bone located at the talus is one of those that form the lower part of the ankle joint. As a legacy from the world of mammals, man has inherited a large number of joints of the lower extremities, in which there are many joints of various bones that provide mobility and make it possible to move in space. The hock joint is inherent in horses, cats, dogs and other animal species. Many people think that people have it. However, in humans it is absent, but in the course of evolution, people have its replacement - the heel analogue. The latter has a similar set of functions that the hock has, and it is closely related to the work of the human musculoskeletal system. It's pretty complex. It includes 6 bones of various shapes and sizes.

The fetlock joint is also characteristic of the world of mammals. Visually, its damage becomes noticeable when the animal begins to limp. In horses, the fetlock is most often affected by arthritis, a disease common to humans. In the process of a person's transition to upright posture, his musculoskeletal system and tissues have changed significantly, and the fetlock joint is absent in the human body today. It is noteworthy that traditional medicine prefers to heal a number of diseases using extracts from animal bones. Beef fetlock is no exception. It contains vitamins and microelements necessary for the restoration of human tissues. It is used to prepare broths, which are recommended for people suffering from fractures and dislocations. The putty joint is widely used in the manufacture of medicines.

Peripheral joints went to man as a heritage of the animal world. They are no less important than the central joints. The defeat of peripheral joints with various arthritis most often affects the elderly, which significantly worsens their quality of life. The facet joints, most commonly referred to as the intervertebral joints, help the spine to be flexible and mobile. This pattern is also present in animals. In them, as in humans, it has a relatively wide joint capsule. If it is broken, the person begins pain in the spine. Pain symptoms cover the neck, thoracic, lumbar. The facet joint got its name because of the unusual shape of its processes. No less interesting is their location in the body - on both sides of the spinal column. Faceted, also called faceted, makes the spine so flexible and mobile. There are various movements between its vertebrae.

Treatment of diseases

The occipital joint is responsible for connecting the skull to the spine. Modern medicine defines this category as atlanto-occipital and atlanto-axial joints. The presence of such joints is a feature of the structure of the human body, but they have their own specifics. Like them, the occipital joint belongs to the category of paired ones, it connects bone tissues of different density. Even at the dawn of studying the structure of the human body, it was found out that the occipital joint has an ellipsoidal shape. Thanks to him, a person can tilt his head forward. If the occipital component is damaged, head movements become limited. Such constructions are vulnerable, and in case of trauma to the back of the head, surgery is often required to restore the occipital component. Titanium plates are also used for this.

In order to treat such diseases and restore damage to their tissues, mankind uses various achievements of scientific and technological progress. Titanium alloy does not cause rejection in the human body, which makes it possible to carry out joint arthroplasty. The titanium element is practically no different from natural, but it is more durable and will allow you to maintain joint mobility in cases where tissue destruction occurs.

The titanium alloy from which the joints are made is today the only chance for many people to avoid disability.

Joint- the place where the bones of a person are connected. Joints are necessary for the mobility of bone joints, and they also provide mechanical support.

The joints are formed by the articular surfaces of the epiphyses of the bones, which are covered with hyaline cartilage, the articular cavity, which contains a small amount of synovial fluid, as well as the articular bag and synovial membrane. In addition, the knee joint contains menisci, which are cartilage formations that have a shock-absorbing effect.

The articular surfaces are coated with hyaline or fibrous articular cartilage, which is 0.2 to 0.5 mm thick. Smoothness is achieved through constant friction, while the cartilage acts as a shock absorber.

The joint capsule (joint bag) is covered with an outer fibrous membrane and an inner synovial membrane and has a connection with the connecting bones at the edges of the articular surfaces, while it seals the articular cavity, thereby protecting it from external influences. The outer layer of the joint capsule is much stronger than the inner one, as it consists of dense fibrous connective tissue, the fibers of which are arranged longitudinally. In some cases, the joint capsule is connected by ligaments. The inner layer of the joint capsule consists of the synovial membrane, the villi of which produce synovial fluid, which provides moisture to the joint, reduces friction and nourishes the joint. This part of the joint has the most nerves.

Joints surround the periarticular tissues, which include muscles, ligaments, tendons, blood vessels, and nerves.

Ligaments of joints consist of dense tissue, they are necessary to control the range of motion of the joints and are located on the outside of the joint capsule, with the exception of the knee and hip joints, where the connections are also inside, providing additional strength.

Blood supply to the joints occurs along the articular arterial network, which includes from 3 to 8 arteries. The innervation of the joints is provided by the spinal and sympathetic nerves. All elements of the joint have innervation, with the exception of hyaline cartilage.

Joints are classified functionally and structurally.

The structural classification of the joints divides the joints according to the type of bone connections, and the functional classification of the joints divides the joints according to the ways of motor functions.

The structural classification of the joints divides them according to the type of connective tissue.

There are three types of joints according to the structural classification:

Fibrous joints- have a dense regular connective tissue rich in collagen fibers.
cartilaginous joints- connections are formed by cartilage tissue.
synovial joints- the bones in this type of joints have cavities and are connected by a dense irregular connective tissue that forms a joint capsule, which usually has additional ligaments.

Functional classification of joints divides joints into the following types:

Synarthrosis joints- joints that are almost completely devoid of mobility. Most of the synarthrosis joints are fibrous joints. For example, they connect the bones of the skull.
Amphiarthrosis joints- joints that provide moderate mobility of the skeleton. Such joints include, for example, intervertebral discs. These joints are cartilaginous joints.

diarthritic joints- joints that provide free movement of joints. These joints include the shoulder joint, hip joint, elbow joint, and others. These joints have a synovial connection. At the same time, diarthrotic joints are divided into six subgroups depending on the type of movement: spherical joints, nut-shaped (cup-shaped) joints, block-shaped (hinged) joints, swivel joints, condylar joints, joints connecting by mutual reception.

Joints are also divided according to the number of axes of motion: monoaxial joints, biaxial joints And multiaxial joints. Joints are also divided into one, two and three degrees of freedom. Also, the joints are divided according to the type of articular surfaces: flat, convex and concave.

There is a division of joints according to their anatomical structure or biomechanical properties. In this case, the joints are divided into simple and complex, it all depends on the number of bones that are involved in the structure of the joint.

simple joint- has two movable surfaces. Simple joints include the shoulder joint and the hip joint.
compound joint A joint that has three or more movable surfaces. Such a joint can be attributed to the wrist joint.
Composite joint- this joint has two or more movable surfaces, as well as an articular disc or meniscus. One such joint is the knee joint.

Anatomically, the joints are divided into the following groups:

Hand joints
Wrist joints
Elbow joints
Axillary joints
Sternoclavicular joints
Vertebral joints
Temporomandibular joints
sacroiliac joints
Hip joints
knee joints
Foot joints

Joint diseases

Joint disease is called arthropathy. When a joint disorder is accompanied by inflammation of one or more joints, this is called arthritis. Moreover, when several joints are included in the inflammatory process, the disease is called polioarthritis, and when one joint becomes inflamed, this is called monoarthritis.

Arthritis is the leading cause of disability in people over 55 years of age. Arthritis comes in several forms, each with different causes. The most common form of arthritis is osteoarthritis or a degenerative joint disease that occurs as a result of joint injury, infection, or old age. Also, according to the studies, it became known that incorrect anatomical development is also the cause of the early development of osteoarthritis.

Other forms of arthritis such as rheumatoid arthritis t and psoriatic arthritis are the result of autoimmune diseases.

Septic arthritis caused by joint infection.

Gouty arthritis is caused by the deposition of uric acid crystals in the joint, which causes subsequent inflammation of the joint.

pseudogout characterized by the formation with deposition of diamond-shaped crystals of calcium pyrophosphate in the joint. This form of arthritis is less common.

There is also such a pathology as hypermobility joints. This disorder occurs most often in young women and is characterized by increased joint mobility as a result of sprained articular ligaments. In this case, the movement of the joint can fluctuate beyond its anatomical limits. This violation is associated with a structural change in collagen. It loses strength and becomes more elastic, which leads to its partial deformation. It is believed that this disorder is hereditary.

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Types of human joints

They can be classified according to functionality:

A joint that does not allow movement is known as synarthrosis. Skull sutures and gomphos (connection of teeth to the skull) are examples of synarthroses. Connections between bones are called syndesmoses, between cartilage - synchordroses, bone tissue - synthostoses. Synarthroses are formed with the help of connective tissue.

Amphiarthrosis allows little movement of the connected bones. Examples of amphiarthrosis are the intervertebral discs and the pubic symphysis.

The third functional class is free-moving diarthrosis. They have the highest range of motion. Examples: elbows, knees, shoulders and wrists. Almost always these are synovial joints.

The joints of the human skeleton can also be classified according to their structure (according to the material of which they are composed):

Fibrous joints are made up of tough collagen fibers. These include the sutures of the skull and the joint that joins the ulna and radius bones of the forearm together.

Cartilaginous joints in humans are made up of a group of cartilages that connect bones together. Examples of such connections would be the joints between the ribs and costal cartilage, as well as between the intervertebral discs.

The most common type, the synovial joint, is a fluid-filled space between the ends of the bones being bonded. It is surrounded by a capsule of rigid dense connective tissue covered with a synovial membrane. The synovial membrane that makes up the capsule produces an oily synovial fluid whose function is to lubricate the joint, reducing friction and wear.

There are several classes of synovial joints, such as ellipsoid, trochlear, saddle and ball joint.

Ellipsoid joints connect smooth bones together and allow them to slide past each other in any direction.

Throat joints, such as the human elbow and knee, restrict movement in only one direction so that the angle between the bones can be increased or decreased. Limited movement in the trochlear joints provides more strength and strength to the bones, muscles and ligaments.

Saddle joints, such as those between the first metacarpal and the trapezium, allow the bones to rotate 360 degrees.

The human shoulder and hip joints are the only ball-and-socket joints in the body. They have the freest range of motion, they are the only ones that can turn on their axis. However, the disadvantage of ball joints is that the free range of motion makes them more susceptible to dislocation than less mobile human joints. In these places, fractures are more common.

Some synovial types of human joints must be considered separately.

trochlear joint

Block joints are a class of synovial. These are the ankles, knee and elbow joints of a person. Typically, a trochlear joint is a ligament of two or more bones where they can only move in one axis to flex or straighten.

The simplest block-like joints in the body are interphalangeal, they are located between the phalanges of the fingers and toes.

Because they have little body mass and mechanical strength assigned to them, they are made up of simple synovial material with tiny extra ligaments for reinforcement. Each bone is covered with a thin layer of smooth hyaline cartilage, designed to reduce friction in the joints. The bones are also surrounded by a capsule of tough fibrous connective tissue covered by a synovial membrane.

The structure of the human joint is always different. For example, the elbow joint is more complex, being formed between the humerus, radius and ulna of the forearm. The elbow is subjected to more severe stress than the joints of the fingers and toes, therefore contains several strong additional ligaments and unique bone structures that strengthen its structure.

The ulna and radius collateral ligaments help support the ulna and radius and strengthen the joints. Human legs also consist of several large block-like joints.

The elbow-like ankle joint is located between the tibia and fibula in the lower leg and the talus in the leg. Branches of the tibia fibula form a bony socket around the talus to limit movement of the leg in one axis. Four additional ligaments, including the deltoid, hold the bones together and strengthen the joint to support the weight of the body.

Located between the thigh and the tibia and fibula of the lower leg, the knee joint is the largest and most complex trochlear joint in the human body.

The elbow joint and ankle joint, whose anatomy is similar, are most often prone to osteoarthritis.

Ellipsoid joint

An ellipsoid joint, also known as a flat joint, is the most common form of synovial joint. They are formed near bones that have a smooth or almost smooth surface. These joints allow the bones to slide in any direction - up and down, left and right, diagonally.

Due to their structure, ellipsoid joints are flexible, while their movement is limited (to prevent injury). Ellipsoid joints are lined with a synovial membrane that produces a fluid that lubricates the joint.

Most ellipsoid joints are found in the appendicular skeleton between the carpal bones of the wrist, between the carpal joints and metacarpal bones of the hand, between the bones of the ankle.

Another group of ellipsoid joints is located between the faces of twenty-six vertebrae in the intervertebral joints. These connections allow us to flex, extend, and rotate the torso while maintaining the strength of the spine, which supports the weight of the body and protects the spinal cord.

Condylar joints

There is a separate type of ellipsoid joints - the condylar joint. It can be considered a transitional form from a block-shaped joint to an ellipsoid one. The condylar joint differs from the block joint in a large difference in the shape and size of the articulating surfaces, as a result of which movement around two axes is possible. The condylar joint differs from the ellipsoid joint only in the number of articular heads.

saddle joint

The saddle joint is a type of synovial joint where one of the bones is shaped like a saddle and the other bone rests on it like a rider on a horse.

Saddle joints are more flexible than ball or ellipsoid joints.

The best example of a saddle joint in the body is the carpometacarpal joint of the thumb, which is formed between the trapezoid bone and the first metacarpal bone. In this example, the trapezium forms a rounded saddle on which the first metacarpal sits. The carpometacarpal joint allows a person's thumb to easily cooperate with the other four fingers of the hand. The thumb is, of course, extremely important to us, as it is what allows our hand to grip objects firmly and use many tools.

ball joint

Ball joints are a special class of synovial joints that have the highest freedom of movement in the body due to their unique structure. The human hip and shoulder joint are the only ball-and-socket joints in the human body.

The two main components of the ball joint are the bone with the ball head and the bone with the cup-shaped notch. Consider the shoulder joint. Human anatomy is so arranged that the spherical head of the humerus (upper arm bone) fits into the glenoid cavity of the scapula. The glenoid cavity is a small and shallow depression that gives the shoulder joint the greatest range of motion in the human body. It is surrounded by a ring of hyaline cartilage, which is the flexible reinforcement of the bone, while muscles—the cuffs of the rotator cuff—hold the humerus within the socket.

The hip joint is somewhat less mobile than the shoulder, but is a stronger and more stable joint. Additional stability of the hip joint is needed to support the weight of the person's body on their feet while performing activities such as walking, running, etc.

At the hip joint, the rounded, almost spherical head of the femur (femur) fits snugly against the acetabulum, a deep recess in the pelvic bone. A sufficiently large number of stiff ligaments and strong muscles hold the head of the femur in place and resist the most severe stresses in the body. The acetabulum also prevents hip dislocations by limiting the movement of the bone within it.

Based on the above, you can make a small table. The structure of the human joint will not be included in it. So, in the first column of the table the type of joint is indicated, in the second and third - examples and their location, respectively.

Human joints: table

joint type	Joint examples	Where are
blocky	Knee, elbow, ankle joint. The anatomy of some of them is given below.	Knee - between the femur, tibia and patella; ulna - between the humerus, ulna and radius; ankle - between the lower leg and the foot.
Ellipsoid	Intervertebral joints; joints between the phalanges of the fingers.	Between the edges of the vertebrae; between the phalanges of the toes and hands.
Globular	Hip and shoulder joint. Human anatomy pays special attention to this type of joints.	Between the femur and pelvic bone; between the humerus and the shoulder blade.
saddle	Carpal-metacarpal.	Between the trapezoid bone and the first metacarpal bone.

To make it clearer what the human joints are, we will describe some of them in more detail.

elbow joint

Human elbow joints, the anatomy of which has already been mentioned, require special attention.

The elbow joint is one of the most complex joints in the human body. It is formed between the distal end of the humerus (more precisely, its articular surfaces - the block and condyle), the radial and block-shaped notches of the ulna, as well as the head of the radius and its articular circumference. It consists of three joints at once: the humeroradial, humeroulnar and proximal radioulnar.

The humeroulnar joint is located between the trochlear notch of the ulna and the block (articular surface) of the humerus. This joint belongs to the block-shaped and is uniaxial.

The shoulder joint is formed between the condyle of the humerus and the head of the humerus. Movements in the joint are made around two axes.

The promaximal radioulnar connects the radial notch of the ulna and the articular circumference of the head of the radius. It is also uniaxial.

There are no lateral movements in the elbow joint. In general, it is considered a trochlear joint with a helical sliding shape.

The largest of the upper body are the elbow joints. Human legs also consist of joints, which simply cannot be ignored.

hip joint

This joint is located between the acetabulum on the pelvic bone and the femur (its head).

This head is covered with hyaline cartilage almost throughout, except for the fossa. The acetabulum is also covered with cartilage, but only near the lunate surface, the rest of it is covered with synovial membrane.

The following ligaments belong to the hip joint: ischio-femoral, ilio-femoral, pubic-femoral, circular zone, as well as a ligament of the femoral head.

The iliofemoral ligament originates at the inferior anterior iliac bone and ends at the intertrochanteric line. This ligament is involved in maintaining the trunk in an upright position.

The next ligament, the ischio-femoral, begins at the ischium and is woven into the capsule of the hip joint itself.

A little higher, at the top of the pubic bone, the pubic-femoral ligament begins, which goes down to the capsule of the hip joint.

Inside the joint itself is a ligament of the femoral head. It starts at the transverse ligament of the acetabulum and ends at the fossa of the femoral head.

The circular zone is made in the form of a loop: it is attached to the lower anterior iliac bone and surrounds the neck of the femur.

The hip and shoulder joints are the only ball joints in the human body.

Knee-joint

This joint is formed by three bones: the patella, the distal end of the femur and the proximal end of the tibia.

The capsule of the knee joint is attached to the edges of the tibia, femur and patella. It is attached to the femur under the epicondyles. On the tibia, it is fixed along the edge of the articular surface, and the capsule is attached to the patella in such a way that its entire anterior surface is outside the joint.

Ligaments of this joint can be divided into two groups: extracapsular and intracapsular. Also in the joint there are two lateral - tibial and peroneal collateral ligaments.

Ankle joint

It is formed by the articular surface of the talus and the articular surfaces of the distal ends of the fibula and tibia.

The articular capsule is attached almost throughout its entire length to the edge of the articular cartilage and recedes from it only on the anterior surface of the talus. On the lateral surfaces of the joint are its ligaments.

The deltoid, or medial ligament, consists of several parts:

- posterior tibio-talar, located between the posterior edge of the medial malleolus and the posterior medial parts of the talus;

- anterior tibio-talar, located between the anterior edge of the medial malleolus and the posteromedial surface of the talus;

- tibiocalcaneal part, extends from the medial malleolus to the support of the talus;

- tibia-navicular part, originates from the medial malleolus and ends at the dorsum of the navicular bone.

The next ligament, calcaneofibular, extends from the outer surface of the lateral malleolus to the lateral surface of the neck of the talus.

Not far from the previous one is the anterior talofibular ligament - between the anterior edge of the lateral malleolus and the lateral surface of the neck of the talus.

And the last, posterior talofibular ligament originates at the posterior edge of the lateral malleolus and ends at the lateral tubercle of the process of the talus.

In general, the ankle joint is an example of a trochlear joint with helical motion.

So, now we definitely have an idea of what human joints are. The anatomy of the joints is more complicated than it seems, and you can see for yourself.

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shoulder joint

It is the most mobile in humans and is formed by the head of the humerus and the glenoid cavity of the scapula.

hip joint

This joint is under heavy load, so it is not surprising that its lesions occupy the first place in the general pathology of the articular apparatus.

Knee-joint

7 early signs of arthritis

8 ways to ruin your knees

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General subtleties

In general, the joint is formed by two joints: the first, main, femoral-tibial, the second is formed by the femur and patella. The joint is complex, it is condylar in type. The joint moves in three mutually perpendicular planes, the first, which is also the most important, is the sagittal one, in which flexion and extension occur, which is carried out in the range from 140 to 145 degrees.

In the frontal plane, there is abduction, adduction, it is insignificant, it is only 5 degrees. In the horizontal plane, rotation occurs inside, outside, small movements are possible in a bent position. From a normal or neutral, bent position, rotation is possible no more than 15-20 degrees.
Additionally, there are two more types of movements, which are represented by sliding, rolling of the articular surfaces of the condyles of the tibia in relation to the femur, occur in front, back, and vice versa.

Biomechanics

The anatomy of the joint is impossible without an understanding of biomechanics, the treatment is based on this. It is complex, its essence lies in the simultaneous movement in several planes. If a person tries to straighten the leg from 90 to 180 degrees, then due to the ligaments, there is a rotation, displacement in front or to the other side of any part of the tibial plateau.

The structure is such that the condyles of both bones are not ideal in relation to each other, so the range of motion increases significantly. Stabilization occurs due to the presence of many ligaments, complemented by adjacent muscles.
Inside the cavity there are menisci, strengthening occurs due to the capsular-ligamentous apparatus, which is covered on top with a muscle-tendon complex.

Soft tissue structures

This is a complex of soft tissues, which, performing a specific function, provide range of motion. These include a large number of formations that have their own structure. In general, children's and adult joints do not differ in their structure.

menisci

These formations consist of connective tissue cartilage, roughly speaking, this is a gasket located between the smooth surfaces of the condyles of the femur, tibia. Their anatomy is such that they contribute to the elimination of incongruence. In addition, their structure involves depreciation, redistribution of the load on the entire surface of the bones. Due to all of the above, the human knee is stabilized, the synovial fluid evenly moves through the joint.

Along their periphery, the menisci are tightly connected to the capsule with the help of ligaments. They differ in strength, because the maximum load falls on the periphery.
During movement, the menisci move along the surface of the tibial plateau, this process does not occur during rupture, therefore, treatment is required. The menisci are reinforced with collateral, cruciate ligaments.

The free edge of the meniscus faces the center, the children's joint, unlike the adult, contains blood vessels. The menisci of an adult have them only along the periphery, which is no more than 1/4. The capsule surrounds everything, which has folds, bags, liquid is produced in them. It is nutrition, a lubricant for cartilage, its total amount does not exceed a teaspoon. Folds replace the cavities of the knee, create additional cushioning.

Ligament apparatus

In the cavity of the knee joint there are formations - cruciate, paired ligaments. They are separated from the cavity with the help of the synovial membrane. Thickness 10 mm, length 35 mm. The anatomy of the human anterior cruciate ligaments is such that they begin with a wide base on the inner or medial surface of the femoral condyle located outwards. Further, their structure differs in that they go from top to bottom inwards, attaching to the anterior surface of the intercondylar eminence on the tibia.

The structure of the ligaments is based on a large number of fibers, which, when combined, form two main bundles. During movement, the load is experienced by each individual bundle of ligaments. Thus, not only the muscles are involved in strengthening the joint, preventing dislocation of the bones. Normally, the anterior cruciate ligament, by its tension, prevents even minimal subluxation of the external condyle, the plateau of the tibia, when the joint is in the most vulnerable position.

The posterior cruciate ligament is 15 mm thick and up to 30 mm long. The beginning takes in the anterior part of the inner condyle of the thigh, following down, outward, is attached to the posterior surface of the intercondylar eminence behind the tuberosity. The structure of the posterior ligament involves the interweaving of part of the fibers into the joint capsule.

The posterior cruciate ligament does not allow the tibia to move backwards, its hyperextension. When a ligament is ruptured in a person, this kind of movement becomes possible, the degree of rupture determines the treatment. The bundle also includes two bundles of fibers.

Extra-articular ligaments

On the inside, the knee is strengthened not only by muscles, but also by the internal collateral ligament. It contains two portions - superficial, deep. The first portion plays the role of a joint stabilizer, consisting of long fibers that fan out from the inner condyle of the thigh, gradually pass to the tibia. The second portion is formed by short fibers, partially woven into the area of the menisci of the human joint. With a complete rupture of the ligament, the treatment is reduced to surgery.

On the outer surface, the human joint is strengthened by external or lateral collateral ligaments. Partially, the fibers of this ligament pass to the back surface, where they participate in additional strengthening. A child's joint contains more elastic fibers in the ligaments of the joint.

muscles

In dynamic terms, in addition to ligaments, muscles are involved in stabilizing the joint. They surround the joint on both sides, complicating its structure. With a partial rupture, the muscles of the knee in a person contribute to its additional stabilization. All muscles have their strength. But the most powerful is the quadriceps, which is involved in the formation of the patellar ligaments.

With pathology, the muscles, especially the quadriceps, begin to atrophy, strength decreases. During the rehabilitation period, treatment is aimed at restoring its function, as the most important.

When it is necessary to repair the posterior instability of the knee, the main treatment is to strengthen the joint after damage to any part of the posterior cruciate ligament. The composition of the posterior muscle group includes semimembranosus, semitendinosus, tender, which are located on the inside of a person, the biceps is located on the outer surface of the thigh.

Norm and pathology of the knee

Understanding the processes occurring in the joint optimizes the treatment, making it more effective. It is not enough to know the structure of a human joint, how it functions matters. An adult, children's joint has articular surfaces that are covered with highly differentiated hyaline cartilage. It consists of chondrocytes, collagen fibers, ground substance, growth layer.
The load that falls on the cartilage is evenly distributed between all components. The structure according to this principle allows you to transfer the load by pressure or shearing nature.

The structure of the knee can be significantly affected by an injury, the mechanism of which largely depends on the treatment. Cartilage can be damaged as a result of excessive impact during sudden braking at the moment of rotation. When the ligaments are damaged, the joint becomes unstable, it begins to shift to the sides. An additional factor complicating treatment can be hemarthrosis, in which blood accumulates in the cavity of the knee joint. The dead cells lead to the release of a large number of lysosomal enzymes, which ultimately leads to the destruction of joint structures.

Basically, in the joint, as a result of external causes, its cartilage is damaged. The degree of damage depends on the strength, duration of the damaging factor. Cracks appear, which are the gates for further destruction of collagen fibers. Vessels sprout from any part of the bone, they lead to a decrease in restorative capacity. The bone is also subject to destruction processes.

The joint has a complex macroscopic, microscopic structure, function, understanding of which helps to treat it correctly.

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Anatomy and joint movement

Every movement in a person's life is regulated by the central nervous system, then the signal is transmitted to the required muscle group. In turn, it sets the required bone in motion. Depending on the freedom of movement of the axis of the joint, an action is performed in one direction or another. The cartilages of the articular surfaces increase the diversity of movement functions.

A significant role is played by muscle groups that contribute to the movement of the joints. Ligaments by structure consist of dense tissue, they provide additional strength and shape. The blood supply passes through the large main vessels of the arterial network. Large arteries branch into arterioles and capillaries, bringing nutrients and oxygen to the articulation and periarticular tissues. Outflow occurs through the venous vascular system.

There are three main directions of movement, they determine the functions of the joints:

Sagittal axis: performs the function of abduction - adduction;
Vertical axis: performs the function of supination - pronation;
Frontal axis: performs the function of flexion - extension.

The structure and forms of joints in medicine are usually divided into classes in a simple way. Joint classification:

Uniaxial. Block type (phalanges of fingers), cylindrical joint (radio-elbow joint).
Biaxial. Saddle joint (carpometacarpal), elliptical type (radiocarpal).
Multi-axis. Spherical joint (hip, shoulder), flat type (sternoclavicular).

Types of joints

For convenience, all joints of the human body are usually divided into types and types. The most popular division is based on the structure of human joints, it can often be found in the form of a table. The classification of individual types of human joints is presented below:

Rotary (cylindrical type). The functional basis of movement in the joints is supination and pronation around one vertical axis.
Saddle type. Articulation refers to this type of connection, when the ends of the surfaces of the bones sit astride each other. The amount of movement occurs axially along its ends. Often there are such joints at the base of the upper and lower extremities.
Spherical type. The structure of the joint is represented by a convex head on one bone and a hollow on the other. This articulation belongs to multiaxial joints. The movements in them are the most mobile of all, and are also the freest. It is represented in the human body by the hip and shoulder joints.
Complex joint. In humans, this is a very complex joint, which is a complex of the body of two or more simple joints. Between them, the articular layer (meniscus or disc) is substituted on ligaments. They hold the bone one near the other, preventing movements to the sides. Types of joints: kneecap.
Combined joint. This connection consists of a combination of several different in shape and isolated from one another joints that perform joint functions.
Amphiarthrosis, or tight joint. It has a group of strong joints. The articular surfaces sharply limit the movements in the joints for greater density, there are practically no movements. In the human body, they are represented where movements are not needed, but a fortress is needed for protective functions. For example, the sacral joints of the vertebrae.
Flat type. This form of joints in humans is represented by smooth, perpendicularly placed joint surfaces in the articular bag. The axes of rotation are possible around all planes, which is explained by the insignificant dimensional difference of the articulating surfaces. These are the bones of the wrist, for example.
Condylar type. Joints whose anatomy has at its base a head (condyle), similar in structure to an ellipse. This is a kind of transitional form between the block-shaped and elliptical types of the structure of the joints.
block type. The articulation here is a cylindrically located process against the lying cavity on the bone and is surrounded by the articular bag. It has a better connection, but less axial mobility than the spherical type of connection.

The classification of joints is quite complicated, because there are a lot of joints in the body and they have a variety of shapes, perform certain functions and tasks.

Connection of cranial bones

The human skull has 8 paired and 7 non-paired bones. They are interconnected by dense fibrous sutures, except for the bones of the lower jaws. The development of the skull occurs as the organism grows. In newborns, the bones of the skull roof are represented by cartilaginous tissue, and the sutures still bear little resemblance to a connection. With age, they get stronger, gradually turning into hard bone tissue.

The bones of the front part adjoin to each other smoothly and are connected by even seams. Unlike them, the bones of the brain section are connected by scaly or jagged sutures. The lower jaw is attached to the base of the skull with a complex elliptical complex biaxial combined joint. Which allows you to move the jaw along all three types of axes. This is due to the daily process of eating.

Joints of the spinal column

The spine is made up of vertebrae, which form articulations with their bodies. The atlas (the first vertebra) is attached to the base of the skull with the help of the condyles. It is similar in structure to the second vertebra, which is called the epistopheus. Together they create a unique mechanism that is unique to humans. It promotes tilting and turning of the head.

The classification of the joints of the thoracic region is represented by twelve vertebrae, which, with the help of spinous processes, are attached to each other and to the ribs. The articular processes are directed frontally, for better articulation with the ribs.

The lumbar region consists of 5 large vertebral bodies, which have a great variety of ligaments and joints. In this department, intervertebral hernias most often occur, due to improper loads and poor muscle development in this area.

Next, follow the coccygeal and sacral sections. In the prenatal state, they are cartilaginous tissue, divided into a large number of parts. By the eighth week they merge, and by the ninth they begin to ossify. At the age of 5–6 years, the coccygeal region begins to ossify.

The entire spine in the sacral region is formed by the age of 28. At this time, separate vertebrae fuse into one department.

The structure of the joints of the belt of the lower extremities

Human legs are made up of many joints, both large and small. They are surrounded by a large number of muscles and ligaments, have a developed network of blood and lymphatic vessels. The structure of the lower limb:

The legs have many ligaments and joints, of which the most mobile is the spherical hip joint. It is him, in childhood, that little gymnasts and gymnasts begin to confidently develop. The largest ligament here is the femoral head. In childhood, it stretches unusually, and this is the reason for the early age of gymnast competitions. At an early level of pelvic formation, the ilium, pubic and ischium bones are laid. They are connected at first by the joints of the girdle of the lower extremities into a bone ring. Only by the age of 16-18 they ossify and fuse into a single pelvic bone.
In medicine, the knee is the most complex and heaviest in structure. It consists of three bones at once, which are in a deep interlacing of joints and ligaments. The knee capsule of the joint itself forms a series of synovial bags, which are located along the entire length of adjacent muscles and tendons that do not communicate with the cavity of the joint itself. The ligaments located here are divided into those that enter the joint cavity and those that do not. At its core, the knee is a condylar type of joint. When it acquires an unbent position, it already works as a block type. When the ankle is bent, rotational movements already occur in it. The knee joint claims to be the most complex joint. At the same time, it must be carefully protected, not zealous with overloads on the legs, because it is very, very difficult to restore it, and at a certain stage it is even impossible.
Concerning the ankle joint, it must be borne in mind that the ligaments lie on its lateral surfaces. It combines a large number of large and small bones. The ankle joint is a blocky type in which helical movement is possible. If we talk about the foot itself, then it is divided into several parts, and does not represent any complex articular joints. In its composition, it has typical block-like joints located between the bases of the phalanges of the fingers. The articular capsules themselves are free and are located along the edges of the articular cartilage.
The foot in human life is the subject of daily stress, and also has an important depreciation effect. It is made up of many small joints.

The structure of the joints of the belt of the upper limbs

The hand includes many joints and ligaments that are able to very finely regulate the actions and motor skills of the smallest movements. One of the most difficult joints here is the shoulder. It has many fastenings and weaves of ligaments that are difficult to adjust one on one. The main three large ligaments that are responsible for abduction, adduction, raising the arms to the sides, anteriorly and upwards.

Raising the arm above the shoulder, sets in motion the muscles and ligaments of the scapula. The shoulder is connected to the scapula with a powerful fibrous ligament, which allows a person to perform various complex and difficult actions with weights.

The classification of the elbow joint in its structure is very similar to the construction of the knee joint. Includes three joints surrounded by one base. The heads at the base of the bones in the elbow joint are covered with hyaline cartilage, which improves gliding. In the cavity of a single joint, blocking of the fullness of movement is distinguished. Due to the fact that the elbow joint involves the movement of the humerus and ulna, lateral movements are not fully performed. They are inhibited by collateral ligaments. The interosseous membrane of the forearm also takes part in the movement of this joint. Overlying nerves and blood vessels pass through it to the end of the arm.

The muscles of the wrist and metacarpus take their beginning of fastening near the wrist joint. Many thin ligaments regulate the motor skills of movement both on the back of the hand and on the sides.

The thumb joint was inherited from monkeys. Human anatomy is similar to the structure of our ancient relatives with this particular joint. Anatomically, it is due to grasping reflexes. This articulation of bones helps to interact with many objects in the environment.

Joint diseases

In humans, the joints are perhaps the most commonly affected by disease. Hypermobility should be singled out among the main pathologies. This is such a process when there is an increased activity of the joints of the bones, which goes beyond the limits of the permissible axes. An unwanted stretching of the ligaments occurs, allowing the joint to make a deep movement, which is extremely bad for the tissues adjacent to the heads of the bones. After some time, such movements lead to deformation of the joint surfaces. This disease is inherited, in what way, it remains to be seen by doctors and scientists.

Hypermobility is often detected in young girls and is genetically determined. It leads to deformation of the connective tissues and, above all, the joints of the bones.

With this type of illness, it is highly discouraged to choose a job in which you have to be in the same position for a long time. In addition, it is necessary to exercise carefully, as there is a risk of even greater overstretching of the ligaments. Which, in turn, ends with varicose veins or arthrosis.

The most common localization of diseases:

Diseases of the shoulder girdle often occur in people in old age, especially in those who are used to earning a living by hard physical labor. In the critical zone are also people who go to the gym very often. Subsequently, old age is accompanied by pain in the shoulders (brachial arthritis) and osteochondrosis of the cervical spine. Often, doctors find osteoarthritis or arthritis of the shoulder joint in people of this category.
Elbow diseases are also common among athletes (epicondylitis). By old age, a person's joints experience discomfort and limited mobility. They are caused by deforming osteoarthritis, arthritis and inflammation of the muscles of the hand. Therefore, it is necessary to remember the correct technique and time of classes.
The joints of the hands, fingers, and hands become inflamed in rheumatoid arthritis. The disease is manifested by the syndrome of "tight gloves". Its peculiarity is the defeat of both hands. Cases of arthrosis with acute damage to the tendons occur in professions associated with fine motor skills: musicians, jewelers, as well as those who type texts on the keyboard daily for a long time.
In the hip region, coxarthrosis is most often isolated. A characteristic disease in the elderly is osteoporosis (softening of the structure of the femur). Bursitis and tendonitis of the hip joint are found in runners and football players.
Diseases in the knee are detected in people of all age groups, as this is a very complex complex. Its restoration in 90% of cases is impossible without surgical intervention, which, in turn, does not guarantee a complete cure for this compound.
Arthrosis and subluxation are characteristic of the ankle. Pathologies are professional in dancers, women who often use high heels. Osteoarthritis affects people who are obese.

Healthy joints are a luxury in our time, which is difficult to notice until a person is faced with their problem. When every movement in a certain joint is done with pain, then a person is able to give a lot to restore health.

It would be difficult to imagine human life without precise and confident movements. Concerning any profession where the physical skill of a person is involved, one must pay tribute to the help of joints and ligaments. They are activated reflexively, and we almost never notice how the slightest movements decide our fate, from driving a car to complex surgical operations. In all this, we are helped by the joints, which can turn life the way you want.

Human leg joints

Joints arose in the body after hard tissues (bone, cartilage) formed into a supporting organ and began to perform this function both in the body itself and in environmental conditions (on land, in water, in air). However, not all bones or cartilage are connected to each other by joints. In some cases, in the absence of diastasis, two bones are interconnected by a dense connective tissue, similar to the interosseous membrane. In other cases, a continuous cartilaginous connection is formed between adjacent bones. Sometimes initially independent bones fuse into a single bone mass. Therefore, some special conditions are necessary for the formation of joints.

To determine what these conditions are, we first analyze the simpler forms of joining bones. So, in conditions when the bone is constantly shifting relative to another bone, connective tissue adhesions are formed - in the form of a membrane connection or various kinds of sutures. These types of connections allow the bones to move relative to each other and at the same time hold them quite firmly at a certain distance. In cases where the range of bone displacement (for example, with age) gradually decreases, the ligamentous apparatus becomes denser and shorter. And finally, there comes a moment when two different bones grow together. The boundaries between them cannot be determined.

In the first case, i.e. with a ligamentous connection, the bones are displaced relative to each other in a large range, and also at the moment of displacement they move away from each other. In the second case, there is not only a decrease in the displacement range, but also a convergence of the bones, which inevitably leads to an increase in the pressure of one bone on another.

A completely different picture is observed in the case of significant bone displacements and the presence of pressure from one bone to another. It is under these conditions that joints with all their characteristic elements are formed. The fact that this is so is evidenced by different types of joints and those components that are indispensable attributes of each joint.

For successful control of the function, it is necessary to know, at least in the most general terms, the biomechanics and structural features of the joints (As the most illustrative example, a general analysis of large joints is given.).

Shoulder joint (articulatio humeri). Formed by the head of the shoulder and the glenoid cavity of the scapula. It has a spherical shape and is the most mobile human joint; surrounded by a thin and loose pouch. The ligamentous apparatus is represented only by the beak-shoulder ligament.

Three mutually perpendicular main axes of rotation can be distinguished. Around the transverse axis, flexion (forward movement) and extension are carried out; around the anterior-posterior axis - abduction and adduction; around the vertical axis - pronation (turn inward) and supination (turn outward); in addition, cone-shaped rotation (circumduction) is possible.

Movements localized strictly in the shoulder joint are performed only within a relatively small range. In all other cases, friendly movements of the entire girdle of the upper limbs (scapula, collarbone) and the spinal column join them.

Muscles play the main role in maintaining the contact of articulating bones, but they often cannot cope with it. With significant fatigue and reflex relaxation of the muscles, the head can separate from the fossa, and after the end of the load, return to its place. This phenomenon is experienced by those who regularly carry fairly large weights. The coincidence of the articular surfaces is also violated when performing movements of the maximum scope - especially flexion and abduction. This, in particular, explains the increased likelihood of injuries to the shoulder joint, which can only be reduced with the help of regular strength training of the muscles surrounding it.

Maximum flexion and abduction in the shoulder joint is limited by the emphasis of the humerus in the humeral process of the scapula (acromion). Some further movement in this direction is also possible after the bones come into contact - due to a violation of the contact between the head and the fossa. In some cases, the sagging bag of the joint may be between the bone stops; there is its infringement, which is eliminated far from immediately. Passive extension is inhibited by strong stretching of the muscles, ligaments of the joint and, to a much lesser extent, by the tension of its bag.

The amplitude of extension and abduction (especially with active execution) depends on turning the arm inward or outward. Supination increases extension by 15-20°. With pronation of the arm, its abduction increases by 20-40 °.

Elbow joint (articulatio cubiti). It is a combination of the humeroulnar and radioulnar proximal joints, which have a common bag and joint cavity.

The main load in most movements is carried by the shoulder joint. It belongs to the block type and has only one - transverse - axis of rotation, around which flexion and extension occur. The shoulder joint has a spherical shape, the proximal radioulnar joint is cylindrical. Thanks to these joints and the radioulnar distal, pronation and supination of the forearm around the longitudinal axis of the joint are carried out. This axis passes through the center of the capitate eminence of the humerus and the center of the head of the ulna. There is also an anterior-posterior axis of rotation, perpendicular to the first two. However, slight movements around this axis are possible only if the forearm is bent relative to the shoulder at an angle of 90 °.

The arc of the trochlea of the humerus reaches 320°, and the trochlear notch of the ulna reaches 180°. This ratio allows movement with a swing of about 140 °.

The ulna and coronoid processes of the ulna, resting against the bottom of the corresponding pits of the humerus, serve as limiters for flexion and extension.

Lateral (collateral) ligaments - the ulnar and radial - strengthen the joint with passive abduction and adduction of the forearm, as well as with significant pronation and supination. An annular ligament of the radius plays an auxiliary role in these movements.

In the vast majority of people, flexion and extension is performed in full and does not require additional training to increase mobility. Natural pronation-supination in everyday life is also quite enough. Special needs may arise when practicing some sports: basketball, table tennis, sports and rhythmic gymnastics, etc. Special exercises (passive rotations of the forearm straightened and bent at an angle of 90°) can increase the amplitude of pronation-supination from 130-140° to 160-180° (in all cases, the magnitude of these movements is measured by the amplitude of rotation of the hand).

With the forearm bent, passively, under the action of an external force, its slight abduction and adduction can be performed. This occurs, for example, in all throwing movements of a "whip-like", ballistic nature. It should be emphasized that these movements are “not provided” by the structure of the elbow joints. During their execution, the radial and ulnar lateral ligaments are overstressed and, if the load is high enough, they are injured.

Thus, when training the elbow joint, the only task is usually to strengthen it. There is no need to develop mobility - it is enough to maintain it at the level necessary to fulfill the set motor tasks. On the contrary, there may be a need to limit excessive mobility - for example, congenital hyperextension in the elbow joint. This is a fairly common phenomenon - mostly of hereditary origin - aggravated by weakness of the muscles of the shoulder and forearm. In some cases, hyperextension reaches 30° (in this case, it is always accompanied by a noticeable abduction of the forearm). It gives the impression of unnaturalness, fragility, vulnerability.

Excessive mobility can be eliminated by powerful forceful tension of the hands (push-ups, pull-ups, weight lifting) with a limited (to the position of the continuation of the shoulder) range of motion of the forearm. Skiing and rowing also have a beneficial effect.

Wrist joint (articulatio radiocarpea). It is formed by the articular surface of the radius and the elliptical surface of the bones of the proximal row of the wrist (scaphoid, lunate and trihedral). The ulna, equipped with a cartilaginous fibrous disc from the lower end, also takes part in the formation of the joint, contributing (especially when resting on the hand) to the distribution of pressure over a large area.

In the wrist joint, flexion, extension, adduction and abduction of the hand are carried out. Its pronation and supination occur along with the rotation of the distal ends of the bones of the forearm. A slight true rotation of the hand is possible only under the action of an external force, due to the elasticity of the cartilage and some mutual removal of the articular surfaces. The amplitude of flexion and extension increases due to the mobilization of a small mobility in the midcarpal and intercarpal joints, which form a complex kinematic chain.

The ligamentous apparatus of the wrist joint is very complex. Going in a variety of directions, ligaments densely braid it from all sides. They are also located between the bones. The main ones are the ulnar and radial lateral (collateral) ligaments of the wrist.

Abduction and adduction of the hand are limited by the contact of the corresponding bones of the wrist and the styloid processes present at the ends of the ulna and radius. The impact of these motion limiters is one of the most common causes of wrist injury. Two main ligaments of the joint are attached to these processes - the lateral ulnar and lateral radial.

Hip joint. Formed by the acetabulum of the pelvic bone and the head of the femur. It has a strong thick capsule reinforced with iliofemoral, ischiofemoral and pubic-femoral ligaments. These ligaments are strongly strained during extension and rotation of the leg from the position of the main stance and remain passive during flexion. The ligament of the femoral head located inside the articular bag is stretched only with extreme adduction of the thigh. In all other cases, it, like a pillow, absorbs the impact of the articular surfaces.

The hip joint has a spherical shape with three main axes of rotation, around which flexion and extension, abduction and adduction, pronation and supination are performed. It has less mobility than the shoulder joint. This is due to the greater congruence (coincidence) of the articular surfaces, a more powerful ligamentous apparatus and the environment of massive muscles. It is almost impossible to fix isolated movements of the hip in the hip joint without special devices, since they are always accompanied by friendly movements of the pelvis and spine. (This explains the significant discrepancies in the data of various authors on the maximum range of hip movements.)

Constant tension of the muscles and ligaments is already observed in the usual standing position. As a result, the hip is gradually fixed in some habitual middle position, and its mobility is limited. Thus, special gymnastics for the joint, aimed primarily at maintaining the natural range of motion and appropriate training of all its elements, becomes necessary.

Rationally constructed training for several months can increase the amplitude of the maximum hip flexion by 30-40° or more.

Extension in the hip joint is inhibited by the tension of the powerful iliac-femoral ligament. Actually, it is stretched already in the position of the main rack and further extension can be extremely insignificant.

Hip abduction limits the contact of the bones - the greater trochanter with the upper edge of the acetabulum. Therefore, any abduction (especially sharp or swing type) must be performed carefully. Increasing hip mobility in this direction requires many years of systematic training. It should be remembered that the supinated (outward-turned) thigh can be abducted much further than the non-supinated one, since in this case the greater trochanter leaves the plane of motion and no longer limits it.

The amount of pronation and especially supination decreases rapidly with age. Systematic exercises allow not only to preserve, but also to significantly increase the amplitude of these movements, affecting mainly the muscles surrounding the joint and the cartilaginous edges of the articular fossa.

Knee joint (articulatio genus). Combines the properties of block-shaped and spherical joints. From the unbent position, only flexion is possible in it. As the flexion progresses, due to a decrease in the radius of curvature of the femoral condyles, the peroneal and tibial lateral ligaments relax. The joint receives another degree of freedom; limited pronation and supination of the leg become possible. The axis of these movements runs vertically - approximately along the center of the medial femoral condyle.

The maximum amplitude of these movements is achieved when the lower leg is bent by 90°. These movements are performed by relatively weak muscles, which are also in unfavorable biomechanical conditions, which increases the risk of joint injury when pronation and supination are performed due to a significant external force. (Such injuries are typical, for example, for alpine skiers who have to manage rather long skis due to intense twisting of the knee joint in one direction or the other.)

The congruence of the articular surfaces is increased by fibrocartilaginous concave pads - menisci. They also help to mitigate shocks and tremors and distribute the pressure of the condyles on a large supporting surface.

Located in the joint cavity between the condyles of the femur, the anterior and posterior cruciate ligaments strengthen the joint - especially during large-scale movements and movements associated with rotation.

The patella is a sesamoid bone. It increases the strength arm of the quadriceps femoris.

In the vast majority of people, there is a complete flexion of the lower leg, until it touches the back of the thigh. Optimal extension - to a position where the lower leg is a continuation of the femur and forms one straight line with it - is carried out without hindrance. This eliminates the need for any training of these movements other than training to strengthen the joint.

Occurring hyperextension is blocked by an increase in the strength of the lateral ligaments and the bag (especially in its back part), as well as the elasticity of the muscles of the lower leg and thigh, which are thrown over the joint. Using a specially simulated load, it is possible to increase the strength of attachment to the articular surface of the shin of the menisci, which can be damaged under strong shock loads directed from top to bottom, and come off from the attachment sites as a result of overextension and excessive rotation.

It is necessary and possible to strengthen the cruciate ligaments, which prevent the femur from slipping forward and backward and are strongly strained during rotation of the lower leg. Strengthening is carried out by applying a moderate, controlled and regular load.

With strong flexion under load, there is, as weightlifters say, a “dead position”, when the powerful efforts of the thigh muscles are only slightly involved in leg extension. Most of them are spent on the deformation of the knee joint: its cup is pressed between the condyles of the femur; all elements of the joint are overstressed - cartilage, ligaments, menisci, numerous synovial bags. The place of attachment of the tendon of the quadriceps femoris on the tibia is also overloaded.

The specific structure of the knee joint causes the formation of X-shaped and O-shaped deviations, which depend on the different relative size of the external and internal condyles of the femur. When compiling a training regimen, this circumstance must be taken into account. Significant deviations from the norm can become an obstacle to the successful practice of some sports. Strengthened training in combination with orthopedic measures can have only a partial normalizing effect.

If, with O-shaped deviations, we measure the length of the leg from the trochanteric point to the support and the distance between the inner epicondyles of the femur, and then multiply this distance by 100 and divide by the length of the limb, then we get the O-shaped index. With an X-shape, the distance between the inner ankles, multiplied by 100, is divided by the length of the leg. The corresponding index of the knee joint is calculated. Deviations with an index up to 3.0 should be considered insignificant; from 3.5 to 5.0 - noticeable; over 5.0 - large.

Ankle joint. Formed by the bones of the lower leg and the talus. It has a block-like shape and one, transverse, axis of rotation. Because the talar block is somewhat narrower posteriorly than anteriorly, as flexion progresses, the joint exhibits limited passive lateral and rotational motion. However, these movements are rather difficult to distinguish, since they are masked by the mobility of the distally located tarsal joints (subtalar, talocalcaneal-navicular, etc.), with which the ankle joint forms a kinematic chain.

Ligaments of the ankle joint are concentrated on its outer and inner sides. They selectively strain at the limit of flexion and extension. At the same time, when the foot is abducted, all ligaments located on the inside of the joint are sharply and strongly stretched; at the moment of adduction - all the ligaments of the outer fan. Movements in the intermediate planes increase the unevenness and asynchrony of the tension of the ligaments, which is one of the reasons for the increased traumatic joint.

Limiting flexion and extension of the foot in the ankle joint limits the emphasis of the edges of the tibia in the neck or in the posterior process of the talus. With prolonged exercise, you can slightly change the configuration of these motion limiters and significantly increase the mobility of the foot. The aging of an insufficiently "involved" ankle joint begins just at the anterior and posterior edges of the talus block.

Spine and body flexibility. The flexibility of the spine (and, to a large extent, of the entire body) is determined by the connections of the vertebral bodies. The angular displacement of the bodies occurs due to the elastic deformation of the intervertebral discs. The magnitude of the angular displacement of two adjacent vertebrae during inclinations and deflections depends mainly on the height and elasticity of the discs. The thickest discs are located in the lumbar spine, the thinnest - in the middle part of the thoracic region, where the relative mobility of adjacent vertebrae is extremely small. In the cervical region, the discs are rather thin, but the height of the vertebral bodies is much less. Therefore, the flexibility of the cervical region is approximately the same as that of the lumbar.

The movements of the spinal column are carried out around three mutually perpendicular axes: transverse - flexion and extension; anterior-posterior - tilts to the right and left; vertical - turns right and left. A complex combination of these movements is carried out with a circular rotation of the body.

Individual fluctuations in the flexibility of various parts of the spine are very large. It has been observed that in people with little flexibility, the degree of angular displacement of the vertebral bodies is mainly regulated by the ligaments that run along the spine. With good flexibility, the muscles of the trunk come to the fore, which, of course, are more extensible. The lower flexibility of the thoracic region when performing any movements is primarily due to the fact that ribs are attached to its vertebrae, which limit the possibility of angular displacement of the vertebrae.

The cervical spine retains some autonomy during trunk movements and does not necessarily participate in these movements. It also implements flexion-extension, right-left tilts and turns. This department requires special exercises and regular study of the joints.

The joints of the chest. Located at the junction of the ribs with the sternum and spine. These are flat, inactive joints that allow only a slight displacement of the bones. Some of them (sternocostal) are even predisposed to overgrowth with cartilage. This tendency increases with age and especially with a passive lifestyle.

No matter how small the mobility of these joints, its significance is very great: thanks to it, with great effect and with less energy, a change in the volume of the chest is carried out during inhalation and exhalation. There is evidence that greater lung capacity is always combined with greater rib mobility, which can be trained. In addition to special exercises, the mobility of the ribs is favorably affected by rowing, swimming, and skiing. It should be noted that training the flexibility of the spine is also an effective means of increasing the mobility of the ribs.

Shoulder joints. Connect the sternum with the collarbone and the collarbone with the scapula. They have both their own mobility and dependent, which is mobilized with all kinds of hand movements and increases their maximum amplitude. This is especially important when the own mobility of the shoulder joint is already mobilized, but is insufficient.

Since the shoulder girdle takes part in inhalation movements, the high mobility of its joints affects the magnitude of the maximum inhalation and exhalation.

Many classifications of joints can be given, in each case taking as a basis a certain property of them. We will consider only those classifications that will help in solving the problem posed in this book.

All joints can be divided into three groups according to the volume of movements performed.

The first group includes joints with extensive range of motion. (shoulder, knee, etc.). For these and similar joints, a large range of motion is characteristic: their articular surfaces are not very congruent, and the difference in the areas of the articular surfaces is very significant; the articular bag and ligamentous apparatus slightly impede movement. It can be said that in this group all the features of the joint, as a type of bone connection, are most clearly expressed.

The second group includes joints with a sharply limited range of motion and semi-joints (flat joints: joints of the vertebral bodies - articulatio inter-vertebralis, sacroiliac joint - articulatio sacroiliaca; tight joints. intercarpal joints - articulatio mediocarpea, joints between the bones of the tarsus - articulationes intertarsea, etc.; semi-joints, pubic fusion - symphysis pubica; connection ribs with sternum, etc.). The listed types of joints are characterized not only by small volumes of movement, but also by a number of structural features. Thus, the articular surfaces of most joints are almost completely congruent; the difference between the areas of the articular surfaces is absent or insignificant; the ligamentous apparatus is usually well developed and significantly inhibits movement; in some cases (for example, in semi-joints) there is no capsule.

The third group includes joints with moderate range of motion. , occupying an intermediate position between the two previously indicated groups (ankle - articulatio talocruralis, wrist - articulatio radiocarpea, etc.). In these joints, all their constituent components are moderately developed.

The classification of joints according to the range of motion attracts attention in that it emphasizes the role of function in the formation of the joint. If a part of the limb of the embryo is isolated from the body (for example, in the area of the future knee joint) and placed in conditions close to the living conditions of a developing organism, then the knee joint will form in the same way as it would develop in the whole embryo: an articular cavity is formed, articular bone ends, capsule, etc. The absence of movements in the joint (and it is known that the movement of the fetus begins in the first months of intrauterine life) leads to the fact that the initially formed joint cavity overgrows, and the articular ends of the bones grow together.

If an adult does not use a limb for a long time and there are no movements in the joint, then after a while the volume of these movements is sharply reduced; subsequently, the so-called ankylosis occurs - the complete absence of movements in this joint. Conversely, with systematic exercises for the development of mobility in the joint, a significant increase in the range of motion can be achieved.

Two important facts follow from these provisions.

1. Hereditary predetermination of the formation of joints exists as a potential possibility of specific motor manifestations, the implementation of which occurs in the process of function. Without normal functioning, this opportunity may remain unrealized.
2. The volume and number of movements performed significantly affect the structure of the joint, the severity of its constituent components (this will be shown in subsequent sections).

Consequently, the nature and volume of movement in the joint will characterize it as a whole, as well as its individual elements. On the other hand, according to the state of the elements of the joint, one can judge the effect of the functional load on a particular joint, i.e. have objective criteria for the development and formation of a particular joint in a given direction. All this allows you to effectively manage the morphogenesis and function of the joint.

The bones in the skeleton are connected in various ways. The simplest type of connection, the most ancient in phylogenetic terms, can be considered a connection through fibrous connective tissue. In this way, for example, parts of the external skeleton in invertebrates are connected. A more complex form of connection between parts of the skeleton is the connection through cartilaginous tissue, for example, in the skeleton of fish. The most developed form of connecting bones in animals living on land was articulation through joints, which made it possible to produce a variety of movements. As a result of a long evolutionary process, all 3 types of compounds have been preserved in humans.

BONE JOINT DEVELOPMENT

Bone joints develop in close relationship with the development of the bones themselves. In humans, continuous connections are first formed as simpler ones - at the 6th week of the prenatal period. In the embryo, in the cartilaginous anlages of the bones, where connections should be formed, a concentration of mesenchyme and convergence of the connecting cartilaginous bone models are observed. At the same time, the mesenchymal layer between them turns into either cartilage or fibrous tissue.

With the development of synovial joints or joints on the 8-9th week, the mesenchyme is rarefied on the epiphyses of the embryo, which leads to the formation of a joint space. By this time, osteoblasts penetrate into the diaphyses of cartilaginous bone models, which form bone tissue. The epiphyses remain cartilaginous, and the mesenchyme covering the future articular surfaces turns into hyaline articular cartilage several millimeters thick. At the same time, the articular capsule begins to form, in which 2 layers can be distinguished: the outer fibrous, consisting of fibrous

connective tissue, and the inner epithelial - the synovial membrane. From the mesenchyme adjacent to the joint, which forms the capsule, the ligaments of the joint are formed.

In the second half of the embryonic period, intraarticular components are formed: discs, menisci, intracapsular ligaments due to the mesenchyme, which is retracted in the form of an elastic cushion between the cartilaginous epiphyses of tubular bones. The formation of the articular cavity occurs not only in the embryonic period, but also in the postnatal period. In different joints, the formation of an intra-articular cavity is completed at different times.

GENERAL ARTROLOGY

Bones can be connected to each other by means of a continuous connection when there is no gap between them. Such a connection is called synarthrosis(synarthrosis). Discontinuous connection, in which a cavity is located between the articulating bones and forms joint(articulation) called diarthrosis, or synovial connection(juncturae synovialis).

Continuous connections of bones - synarthrosis

Continuous connections of bones (Fig. 32), depending on the type of tissue connecting the bones, are divided into 3 groups: fibrous joints (juncturae fibrosae), cartilaginous joints (juncturae cartilagina) and connections through bone tissue - synostosis (synostoses).

to fibrous junctions include syndesmosis, interosseous membrane and suture.

syndesmosis(syndesmosis) is a fibrous connection through ligaments.

Bundles(ligamenta) serve to strengthen bone joints. They can be very short, such as interspinous and intertransverse ligaments. (ligg. interspinalia et intertransversaria), or, conversely, long, like the supraspinous and nuchal ligaments (ligg. supraspinale et nuchae). Ligaments are strong fibrous strands, consisting of longitudinal, oblique and overlapping bundles of collagen and a small amount of elastic fibers. They can withstand a large tensile load. A special type of ligaments are yellow ligaments (ligg. flava), made up of elastic fibers. They are durable and

Rice. 32. Continuous connections:

a - syndesmosis; b - synchondrosis; in - symphysis; d, e, f - driving in (dentoalveolar connection); g - jagged seam; h - scaly seam; and - flat (harmonious) seam; to - interosseous membrane; l - ligaments

the strength of fibrous syndesmoses, however, they are characterized by great extensibility and flexibility. Such ligaments are located between the arches of the vertebrae.

A special type of syndesmosis is dentoalveolar syndesmosis or inclusion(gomphosis)- the connection of the roots of the teeth with the dental alveoli of the jaws. It is carried out by fibrous bundles of periodontium, going in different directions, depending on the direction of the load on this tooth.

Interosseous membranes: radioulnar syndesmosis (syndesmosis radioulnaris) and tibiofibular (syndesmosis tibiofibularis). These are the connections of adjacent bones through the interosseous membranes - respectively, the interosseous membrane of the forearm and interosseous membrane of the leg (membrane interossea cruris). Syndesmoses also close holes in the bones: for example, the obturator opening is closed by the obturator membrane (membrana obturatoria), there are atlantooccipital membranes - anterior and posterior (membrana atlantooccipitalis anterior et posterior). Interosseous membranes close the holes in the bones, increase the surface for muscle attachment. The membranes are formed by bundles of collagen fibers, are inactive, have openings for blood vessels and nerves.

The seam(sutura) is a joint in which the edges of the bones are firmly articulated with a small layer of connective tissue. The sutures are found only on the skull. Depending on the shape of the edges of the skull bones, the following seams are distinguished:

jagged (sut.serrata)- the edge of one bone has teeth that enter the recesses between the teeth of another bone: for example, when connecting the frontal bone to the parietal;

Scaly (sut. squamosa) is formed by superimposing obliquely cut bones on top of each other: for example, when the scales of the temporal bone are connected to the parietal;

Flat (sut. plana)- the even edge of one bone is adjacent to the same edge of the other, characteristic of the bones of the facial skull;

shindylosis (splitting; schindylesis)- the sharp edge of one bone enters between the split edges of another: for example, the connection of the vomer with the beak of the sphenoid bone.

in cartilage joints(juncturae cartilaginea) Bones are held together by layers of cartilage. Such compounds include synchondrosis And symphysis

Synchondrosis(synchondrosis) formed by continuous layers of cartilage. This is a strong and elastic connection with little mobility, which depends on the thickness of the cartilage layer: the thicker the cartilage, the greater the mobility, and vice versa. Synchondroses are characterized by spring functions. An example of synchondrosis is a layer of hyaline cartilage at the border of the epiphyses and metaphyses in long tubular bones - the so-called epiphyseal cartilage, as well as the costal cartilages connecting the ribs to the sternum. Synchondrosis can be temporary or permanent. The former exist until a certain age, for example, epiphyseal cartilages. Permanent synchondrosis remains throughout a person's life, for example, between the pyramid of the temporal bone and neighboring bones - the sphenoid and occipital.

Symphyses(symphyses) differ from synchondrosis in that there is a small cavity inside the cartilage connecting the bones. Bones are also held together by ligaments. The symphyses were previously called semi-joints. There is a symphysis of the handle of the sternum, an intervertebral symphysis and a pubic symphysis.

If a temporary continuous connection (fibrous or cartilage) is replaced by bone tissue, then it is called synostosis(synostosis). An example of synostosis in an adult is the connections between the bodies of the occipital and sphenoid bones, between the sacral vertebrae, and halves of the lower jaw.

Discontinuous connections of bones - diarthrosis

Discontinuous connections of bones - joints(juncturae synovialis), or synovial joints, diarthrosis,- formed from continuous connections and are the most progressive form of bone connection. Each joint has the following components: joint surfaces, covered with articular cartilage; joint capsule, covering the articular ends of the bones and reinforced with ligaments; articular cavity, located between the articulating surfaces of the bones and surrounded by the articular capsule, and articular ligaments that strengthen the joint (Fig. 33).

Articular surfaces(facies articularis) covered with articular cartilage (cartilago articularis). Usually one of the articulating articular surfaces is convex, the other is concave. The structure of cartilage may be hyaline or, less commonly, fibrous. The free surface of the cartilage facing the joint cavity is smooth, which facilitates movement

Rice. 33. Scheme of the structure of the joint:

1 - synovial membrane; synovial layer; 2 - fibrous membrane; fibrous layer; 3 - fat cells; 4 - joint capsule; 5 - hyaline articular cartilage; 6 - mineralized cartilage matrix; 7 - bone; 8 - blood vessels; 9 - articular cavity

bones relative to each other. The inner surface of the cartilage is firmly connected to the bone, through which it receives nutrition. The elasticity of hyaline cartilage softens shocks. In addition, cartilage smooths out all the roughness of the articulating bones, giving them the appropriate shape and increasing the congruence (coincidence) of the articular surfaces.

joint capsule(capsula articularis) covers the articular surfaces of the bones and forms a hermetically closed articular cavity. The capsule consists of two layers: outer - fibrous membrane (membrana fibrosa) and internal - synovial membrane (membrana synovialis). The fibrous membrane is formed by fibrous connective tissue. In joints that perform extensive movements, the capsule is thinner than in inactive ones.

The synovial membrane consists of loose connective tissue, which is covered by a layer of epithelial cells. The synovial membrane forms special outgrowths - synovial villi (villi synoviales), involved in the production of synovial fluid (synovia). The latter moisturizes the articular surfaces, reducing their friction. In addition to villi, the synovial membrane has synovial folds. (plicae synoviales), protruding into the joint cavity. Fat can be deposited in them, and then they are called fat folds. (plicae adipose). If the synovial membrane bulges outward, then synovial bags (bb. synoviales). They are located in places of greatest friction, under the muscles or tendons. In addition, in large joints, the synovial membrane can form more or less closed cavities - inversions of the synovial membrane. (recessus synoviales). Such inversions, for example, are present in the articular capsule of the knee joint.

Articular cavity(cavitas articularis) is a slit-like space bounded by the articular surfaces of the bones and the articular capsule. It is filled with a small amount of synovial fluid. The shape and dimensions of the articular cavity depend on the size of the articular surfaces and the places of attachment of the capsule.

In addition to the main components considered in each joint, additional formations are observed: the articular lip, articular discs, menisci, ligaments and sesamoid bones.

articular lip (labrum articulare) consists of fibrous tissue attached along the edge of the articular cavity. It increases the area of contact of the articular surfaces. For example, the articular lip is present in the shoulder and hip joints.

articular disc (discus articularis) and articular meniscus (meniscus articularis) are fibrous cartilage located in the joint cavity. If the cartilage divides the joint cavity completely into 2 floors, which is observed, for example, in the temporomandibular joint, then they speak of a disc. If the separation of the joint cavity is incomplete, then they speak of menisci: for example, menisci in the knee joint. Articular cartilage promotes congruence of the articulating surfaces and reduces the effect of shocks.

Intracapsular ligaments (ligg. intracapsularia) consist of fibrous tissue and connect one bone to another. From the side of the joint cavity, they are covered with a synovial membrane of the joint capsule,

which separates the ligament from the joint cavity: for example, the ligament of the head of the femur in the hip joint. The ligaments that strengthen the joint capsule and lie in its thickness are called capsular ligaments. (ligg. capsularia), and located outside the capsule - extracapsular (ligg. extracapsularia).

Sesamoid bones (ossa sesamoidea) located in the capsule of the joint or in the thickness of the tendon. Their inner surface, facing the joint cavity, is covered with hyaline cartilage, the outer surface is fused with the fibrous layer of the capsule. An example of a sesamoid bone located in the capsule of the knee joint is the patella.

Types of joints

Joints are subdivided depending on the shape and number of articulating surfaces or functions (the number of axes around which movements are made in the joint). There are the following forms of movements in the joints:

Movement around the frontal axis: decrease in the angle between the articulating bones - bending(flexio) increasing the angle between them - extension(extensio);

Movement around the sagittal axis: approaching the median plane - cast(adductio), distance from her abduction(abductio);

Movement around the vertical axis: outward rotation(supinatio);internal rotation(pronatio);circular rotation(circumductio), in which the rotating limb segment describes a cone.

The range of motion in the joints is due to the peculiarities of the shape of the articulating bone surfaces. If one surface is small and the other is large, then the range of motion in such a joint is large. In joints with almost identical articular surfaces, the range of motion is much less. In addition, the range of motion in the joint depends on the degree of its fixation by ligaments and muscles.

The shape of the articular surfaces is conditionally compared with geometric bodies (ball, ellipse, cylinder). They are classified according to their shape and distinguish between spherical, flat, elliptical, saddle, block and other joints. According to the number of axes, multiaxial, biaxial, uniaxial joints are distinguished. The shape of the articular surfaces also determines the functional mobility of the joints and, therefore,

number of axles. According to the shape and number of axes, one can distinguish: uniaxial joints - block-shaped, cylindrical; biaxial joints - ellipsoid, condylar, saddle; multiaxial joints - spherical, flat. Movements in the joint are determined by the shape of its articular surfaces (Fig. 34).

Uniaxial joints. IN cylindrical joint(articulatio cylindrica) the articular surface of one bone has the shape of a cylinder, and the articulating surface of the other bone is a cavity. In the radioulnar joint, movements are made inward and outward - pronation and supination. The cylindrical joint is the articulation of the atlas with the axial vertebra. Another form of uniaxial joints is blocky(ginglymus). In this joint, one of the articulating surfaces is convex with a groove in the middle, the other articular surface is concave and has a scallop in the middle. Groove and scallop prevent side slip. An example of a block joint is the interphalangeal joints of the fingers, which provide flexion and extension. A type of block joint - helical joint(articulatio cochlearis), in which the groove on the articulating surface is somewhat oblique with respect to a plane perpendicular to the axis of rotation. As this furrow continues, a screw is formed. These joints are the ankle and shoulder joints.

Biaxial joints.Elliptical joint(articulatio ellipsoidea) the shape of the articular surfaces approaches an ellipse. In this joint, movements are possible around two axes: frontal - flexion and extension, and sagittal - abduction and adduction. In biaxial joints, circular rotation is possible. Examples of biaxial joints are the wrist and atlantooccipital. Biaxial also include saddle joint(articulatio sellaris), the articulated surfaces of which resemble a saddle in shape. The movements in this joint are the same as in the ellipsoid. An example of such a joint is the carpometacarpal joint of the thumb. condylar joint(articulatio bicondylaris) refers to biaxial (according to the shape of the articular surfaces, it approaches the ellipsoid). In such a joint, movements around two axes are possible. An example is the knee joint.

Multiaxial (triaxial) joints.ball joint(articulatio sphenoidea) has the greatest freedom of movement. It is possible

Rice. 34.1.Synovial joints (joints). Types of joints according to the shape and number of axes of rotation:

a - uniaxial joints: 1, 2 - block joints; 3 - cylindrical joint; b - biaxial joints: 1 - elliptical joint; 2 - condylar joint; 3 - saddle joint;

c - triaxial joints: 1 - spherical joint; 2 - bowl-shaped joint; 3 - flat joint

Rice. 34.2.Schemes of movements in the joints:

a - triaxial (multiaxial) joints: 1 - spherical joint; 2 - flat joint; b - biaxial joints: 1 - elliptical joint; 2 - saddle joint; c - uniaxial joints: 1 - cylindrical joint; 2 - block joint

movements around three mutually perpendicular axes: frontal, sagittal and vertical. Around the first axis, flexion and extension occur, around the second - abduction and adduction, around the third - rotation outward and inward. An example is the shoulder joint. If the articular cavity is deep, as in the hip joint, where the head of the femur is deeply covered by it, then such a joint is called bowl-shaped(articulatio cotylica). The multiaxial joints are flat joint(articulatio plana), the articular surfaces of which are slightly curved, are segments of a circle of large radius. These are, for example, the joints between the articular processes of the vertebrae.

If 2 bones take part in the formation of the joint, then the joint is called simple(articulatio simplex), if 3 or more difficult(articulatio composita). An example of a simple joint is the shoulder, a complex one is the elbow. Combined joints- a set of several joints in which movements are performed simultaneously. For example, movement in one temporomandibular joint is impossible without movement in the other.

In the fixation of the joints, a number of factors are important: the adhesion of the articular surfaces, their strengthening by the capsular-ligamentous apparatus, the traction of the muscles and tendons attached in the circumference of the joints.

Articulations have pronounced individual, age and gender characteristics. Mobility in bone joints depends on the individual structural features of these joints. It is not the same in people of different ages, genders and fitness levels.

Blood supply and innervation of the joints

The joints are supplied with blood by the branches of the main arterial trunks that pass nearby. Sometimes a vasculature of several arteries forms on the surface of the joint, for example, the arterial networks of the elbow and knee joints. The outflow of venous blood occurs in the venous vessels that accompany the arteries of the same name. The innervation of the joints is carried out by the nearest nerves. They send nerve branches to the articular capsule, forming a number of branches and terminal nerve apparatuses (receptors) in it. Lymph outflow occurs to nearby regional lymph nodes.

CONNECTION OF THE BONES OF THE TRUNK

Connection of the spinal column

The vertebral bodies are connected by intervertebral symphysis(symphysis intervertebralis); located between the vertebral bodies intervertebral discs(disci intervertebrals). The intervertebral disc is a fibrocartilaginous formation. Outside, it is formed by the fibrous ring (anulus fibrosus) fibers of which go in an oblique direction to adjacent vertebrae. The nucleus pulposus is located in the center of the disc. (nucl. pulposus), which is the remainder of the dorsal string (chord). Due to the elasticity of the disc, the spinal column absorbs the shocks that the body experiences when walking and running. The height of all intervertebral discs is 1/4 of the entire length of the spinal column. The thickness of the discs is not the same everywhere: the largest in the lumbar region, the smallest - in the thoracic.

2 longitudinal ligaments pass through the vertebral bodies - anterior and posterior (Fig. 35). Anterior longitudinal ligament(lig. longitudinale a nterius) located on the anterior surface of the vertebral bodies. It starts from the anterior tubercle of the atlas arch and extends to the 1st sacral vertebra. This ligament prevents excessive extension of the spine. Posterior longitudinal ligament(lig. longitudinal posterius) goes inside the spinal canal from the body of the II cervical vertebra to the I sacral. It prevents excessive flexion of the spine.

Connections between arcs and processes are referred to as syndesmoses. So, between the arches of the vertebrae, strong yellow ligaments(ligg. flava), between the spinous processes of the vertebrae - interspinous ligaments(ligg. interspinalia), which at the tops of the processes pass into supraspinous ligaments(ligg. supraspinalia), running in the form of a round longitudinal strand along the entire length of the spinal column. In the cervical region, the ligaments above the VII vertebra thicken in the sagittal plane, go beyond the spinous processes and attach to the external occipital protrusion and crest, forming nuchal ligament(lig. nuchae). Between the transverse processes of the vertebrae are intertransverse ligaments(ligg. intertransversaria).

Rice. 35. Connections of the spinal column: a - side view (partially removed the left half of the vertebrae): 1 - vertebral body; 2 - intervertebral disc; 3 - posterior longitudinal ligament; 4 - anterior longitudinal ligament; 5 - facet joint (opened); 6 - interspinous ligament; 7 - yellow ligament; 8 - supraspinous ligament; 9 - intervertebral foramen;

b - rear view from the spinal canal (the arches of the vertebrae are removed): 1 - posterior longitudinal ligament; 2 - intervertebral disc; c - view from the side of the spinal canal to the vertebral arches: 1 - vertebral arch; 2 - yellow ligament

facet joints

The lower articular processes of the vertebra articulate with the superior articular processes of the underlying vertebra by means of facet joints(articulationes zygapophysiales). According to the shape of the articular surfaces, they are flat, and in the lumbar spine - cylindrical.

lumbosacral joint(articulatio lumbosacralis) between the sacrum and the fifth lumbar vertebra has the same structure as the articulation of the vertebrae between them.

sacrococcygeal joint(articulatio sacrococcygeal) has some features in connection with the loss of the coccyx characteristic of the structure of the vertebrae. Between the bodies of the V sacral and I coccygeal vertebrae there is an intervertebral disc, as in the true joints of the vertebrae, but inside it, instead of the nucleus pulposus, there is a small cavity. Passes along the anterior surface of the coccyx ventral sacrococcygeal ligament(lig. sacrococcygeum ventrale), which is a continuation of the anterior longitudinal ligament. On the back surface of the bodies of the sacral vertebrae and the coccyx is deep dorsal sacrococcygeal ligament(lig. sacrococcygeum dorsale profundum)- continuation posterior longitudinal ligament(lig. longitudinal posterius). The lower sacral foramen is closed superficial posterior sacrococcygeal ligament(lig. sacrococcygeum posterius superficialis), going from the dorsal surface of the sacrum down to the back surface of the coccyx. It corresponds to the supraspinous and yellow ligaments. Lateral sacrococcygeal ligament(lig. sacrococcygeum laterale) goes along the lateral surface of the sacrum and coccyx.

CONNECTION OF I AND II NECK VERTEBRAE BETWEEN THEM AND WITH THE SKULL

The connections of the condyle in the occipital bone with the superior articular fossa of the atlas form a combined elliptical atlantooccipital joint(articulatio atlantooccipitalis). In the joint, movements around the sagittal axis are possible - tilting the head to the sides and around the frontal axis - flexion and extension. The connection of the atlas and the axial vertebra forms 3 joints: paired combined flat lateral atlantoaxial joint(articulatio atlantoaxial lateralis), located between the lower articular surfaces of the atlas and the upper articular surfaces of the axial vertebra; unpaired cylindrical median atlantoaxial joint(articulatio atlantoaxialis medialis), between the tooth of the axial vertebra and the articular fossa of the atlas. The joints are reinforced with strong ligaments. Between the anterior and posterior arches of the atlas and the edge of the foramen magnum are stretched anterior and posterior atlantooccipital membranes(membranae atlantooccipitales anterior et posterior)(Fig. 36). Between the lateral masses, the atlas is thrown transverse ligament of atlas(lig. trasversum atlantis). From the upper free edge of the transverse ligament passes fibrous

Rice. 36. The connection of the cervical vertebrae with each other and with the skull: a - cervical spine, view from the right side: 1 - interspinous ligament; 2 - yellow ligaments; 3 - nuchal ligament; 4 - posterior atlantooccipital membrane; 5 - anterior atlantooccipital membrane; 6 - anterior longitudinal ligament;

b - the upper part of the spinal canal, rear view. Removed vertebral arches

and spinous processes: 1 - lateral atlantoaxial joint; 2 - atlantooccipital joint; 3 - occipital bone; 4 - cover membrane; 5 - posterior longitudinal ligament; c - in comparison with the previous figure, the integumentary membrane is removed: 1 - transverse ligament of the atlas; 2 - pterygoid ligaments; 3 - cruciate ligament of the atlas; d - in comparison with the previous figure, the cruciate ligament of the atlas has been removed:

1- ligament of the top of the tooth; 2 - pterygoid ligament; 3 - atlantooccipital joint; 4 - lateral atlantoaxial joint;

e - median atlanto-axial joint, top view: 1 - transverse ligament of the atlas;

2- pterygoid ligament

cord to the anterior semicircle of the foramen magnum. From the lower edge of the same ligament down to the body of the axial vertebra, there is a fibrous bundle. The superior and inferior fiber bundles, together with the transverse ligament, form cruciate ligament of atlas(lig. cruciforme atlantis). From the upper part of the lateral surfaces of the odontoid process, two pterygoid ligaments(ligg. alaria), heading to the condyles of the occipital bone.

SPINE COLUMN IN GENERAL

vertebral column(columna vertebralis) consists of 24 true vertebrae, sacrum, coccyx, intervertebral discs, articular and ligamentous apparatus. The functional significance of the spine is enormous. It is a container for the spinal cord, which lies in the spinal canal (canalis vertebralis); serves as a support for the body, participates in the formation of the chest and abdominal walls.

There are intervertebral foramen between the upper and lower vertebrae. (forr. intervertebralia), where the spinal nodes lie, vessels and nerves pass. The intervertebral foramina are formed by the lower notch of the overlying vertebra and the upper notch of the underlying one.

The human spine has curves in the sagittal plane (see Fig. 18.1). In the cervical and lumbar regions, the spine forms bends directed by a bulge anteriorly, - lordosis(lordosis) and in the thoracic and sacral sections - bends directed backwards - kyphosis(kyphosis). The bends of the spinal column give it spring properties. Bends are formed in the postnatal period. At the 3rd month of life, the child begins to raise his head, cervical lordosis appears. When the child begins to sit, thoracic kyphosis is formed (6 months). When moving to a vertical position, lumbar lordosis occurs (8-9 months). The final formation of bends ends by the age of 18. Lateral curves of the spine in the frontal plane - scoliosis- are pathological curvature. In old age, the spine loses its physiological curves, as a result of the loss of elasticity, a large thoracic curve, the so-called senile hump, is formed. In addition, the length of the spine may decrease by 6-7 cm. Movements in the spinal column are possible around 3 axes: frontal - flexion and extension, sagittal - tilt to the right and left, vertical - rotational movements.

X-ray anatomy of the spinal column

To study the structure of the spinal column, radiography is used in frontal and lateral projections.

On radiographs in lateral projections, the vertebral bodies and intervertebral fissures corresponding to the intervertebral discs, vertebral arches, spinous and articular processes, articular fissures, and intervertebral foramina are visible. The shadows of the transverse processes are superimposed on the shadows of the vertebral bodies. Radiographs of the spinal column allow you to study its bends and structural features of each department.

On radiographs in frontal projections, details of the structure of the vertebrae and intervertebral fissures are also visible, and the transverse processes in the cervical and lumbar spine are free from overlaps, and in the chest they are combined with the posterior ends of the ribs. The spinous processes are superimposed on the vertebral bodies. X-rays of the sacrum and coccyx show sacral foramina, lumbosacral and sacroiliac joints.

CHEST JOINTS

Connecting the ribs to the sternum and spine

Seven true ribs are connected to the sternum with the help of costal cartilages, and the cartilage of the 1st rib is connected by synchondrosis to the handle of the sternum. The remaining 6 costal cartilages (II-VII) form flat sternocostal joints(articulationes sternocostales). Between the cartilages of the VI-VIII ribs there are joints called intercartilaginous(articulationes interchondrales).

The ribs are connected to the vertebrae by costovertebral joints(articulationes costovertebral), consisting of two joints. One of them is the joint of the head (articulatio capitis costae), the other is the costotransverse joint (articulatio costotransversaria) between the costal tubercle and the transverse process of the vertebra (Fig. 37).

OVERALL CHEST

Rib cage(compages thoracis) formed by 12 pairs of ribs with cartilage, 12 thoracic vertebrae, sternum and articular-ligamentous apparatus. The chest is involved in the protection of organs located

Rice. 37. Connecting the ribs to the sternum and spine:

a - connection with the sternum: 1 - costal cartilages; 2 - radiant sternocostal ligament; 3 - clavicle; 4 - interclavicular ligament; 5 - articular disc of the sternoclavicular joint; 6 - costoclavicular ligament; 7 - cavities of the sternocostal joints; 8 - intercartilaginous joints;

b - with the spine: 1 - anterior longitudinal ligament; 2 - costal fossa on the vertebral body; 3 - costal fossa on the transverse process of the vertebra; 4 - rib; 5 - the joint of the head of the rib, strengthened by the radiant ligament

in the chest cavity. The chest has 2 openings (apertures) - upper and lower.

Upper thoracic inlet (apertura thoracis superior) bounded behind by the body of the 1st thoracic vertebra, from the sides - by the 1st rib, in front - by the sternum. Inferior thoracic aperture (apertura thoracis inferior) bounded behind by the body of the XII thoracic vertebra, from the sides and in front - by the XI and XII ribs, costal arches and the xiphoid process. Right and left costal arches (arcus costales), formed by the last of the ribs connecting with the sternum (X), form the infrasternal angle (angulus infrasternalis), whose dimensions are determined by the shape of the chest. The spaces between adjacent ribs are called intercostal spaces. (spatium intercostal).

The shape of the chest is different and depends on the physique, age and gender. There are two extreme forms of the chest: narrow and

long, with low ribs and a sharp infrasternal angle; wide and short, with a greatly expanded lower aperture and a large infrasternal angle. The chest of a woman is more rounded, steeper and narrower in the lower section. In men, it approaches a cone in shape, all of its sizes are larger.

X-ray anatomy of the chest

On a chest radiograph in the anteroposterior projection, dorsal segments of the ribs are seen, having a direction laterally and downward, and anterior segments of the ribs, having the opposite direction. Costal cartilages do not give shadows. The sternoclavicular joints, sternum, intercostal spaces are clearly visible.

Questions for self-control

1. List the types of connections. Give them a description.

2. What are the types of joints according to the shape and number of axes? Describe each type of connection.

3. Name the continuous connections of the bones.

4. What additional formations in the joint do you know? What function do they perform?

5. How are the vertebral bodies connected to each other?

6. How are the I and II cervical vertebrae connected to each other and to the skull?

7. What forms of the chest are found depending on the physique, age and gender?

CONNECTION OF LIMB BONES

Joints of the upper limb

Joints of the girdle of the upper limb

acromioclavicular joint(articulatio acromioclavicularis) formed by the acromial end of the clavicle and the acromion of the scapula. The articular surface is flat. Movements in the joint are possible around all 3 axes, but their amplitude is very small. Inside the joint cavity there is articular disc(discus articularis). The joint is strengthened by the following ligaments: coracoclavicular (lig. coracoclaviculare), running from the coracoid process of the scapula to the lower surface of the clavicle, as well as

acromioclavicular (lig. acromioclaviculare), located between the clavicle and the acromion.

The coracoacromial ligament is also isolated in the girdle of the upper limb. (lig. coracoacromiale) in the form of a triangular plate located between the acromion of the scapula and the coracoid process. This ligament is the arch of the shoulder joint and limits the abduction of the arm upward.

sternoclavicular joint(articulatio sternoclavicularis)(Fig. 38) is formed by the clavicular notch of the sternum and the sternal end of the clavicle. To increase the conformity of the articular surfaces inside the joint cavity, there is an articular disc that divides the joint cavity into 2 sections. The shape of the articulated surfaces of the bones is saddle-shaped. In terms of range of motion due to the disk, the joint approaches spherical. Movement around the sagittal axis up and down, around the vertical axis forward and backward, as well as rotation of the clavicle around the frontal axis and a slight circular movement are possible. The joint is strengthened by the following ligaments: costoclavicular (lig. costoclavicular), going from the cartilage of the 1st rib to the lower surface of the clavicle; anterior and posterior sternoclavicular (ligg. sternoclaviculares anterius et posterius), passing in front and behind due to the disk of the joint; interclavicular ligament (lig. interclaviculare), which connects both sternal ends of the clavicle above the jugular notch.

Rice. 38.The sternoclavicular joint, front view. The right joint was opened by a frontal incision:

1 - articular disc; 2 - interclavicular ligament; 3 - anterior sternoclavicular ligament; 4 - clavicle; 5 - costoclavicular ligament; 6 -I rib; 7 - handle of the sternum

Joints of the free upper limb shoulder joint

shoulder joint(articulatio humeri)(Fig. 39) is formed by the head of the humerus and the glenoid cavity of the scapula. There is a discrepancy between the articulated surfaces of the bones; to increase congruence, an articular lip is formed along the edge of the glenoid cavity (labrum glenoidale). The articular capsule is thin, free, starts from the edge of the articular lip and is attached to the anatomical neck of the humerus. The tendon of the long head of the biceps brachii passes through the joint cavity. It lies in the intertubercular groove of the humerus and is surrounded by a synovial membrane. The joint is strengthened by the coraco-brachial ligament (lig. coracohumerale), starting from the coracoid process of the scapula and woven into the joint capsule. The shoulder joint is surrounded by muscles from the outside. Muscle tendons surrounding

Rice. 39. Shoulder joint, right, front view (capsule and ligaments of the joint): 1 - coraco-brachial ligament; 2 - coracoid-acromial ligament; 3 - coracoid process; 4 - scapula; 5 - joint capsule; 6 - humerus; 7 - tendon of the long head of the biceps of the shoulder; 8 - tendon of the subscapularis muscle; 9 - acromion

squeezing the joint, not only strengthen it, but also, when moving in the joint, pull back the joint capsule, preventing its infringement. According to the shape of the articulated surfaces, the joint refers to spherical. Movements in the joint are possible around three mutually perpendicular axes: sagittal - abduction and adduction, vertical - pronation and supination, frontal - flexion and extension. Circular rotations are possible in the joint.

elbow joint

elbow joint(articulatio cubiti) is complex and consists of 3 joints: humeroulnar, humeroradial and proximal radioulnar. They have a common cavity and are covered with one capsule (Fig. 40).

Rice. 40.Elbow joint, front view:

a - external view: 1 - radius; 2 - tendon of the biceps muscle of the shoulder; 3 - annular ligament of the radius; 4 - radial collateral ligament; 5 - joint capsule; 6 - humerus; 7 - ulnar collateral ligament; 8 - ulna; b - joint capsule removed: 1 - articular cartilage; 2 - adipose tissue; 3 - synovial membrane

Shoulder joint(articulatio humeroulnaris) formed by the trochlea of the humerus and the trochlear notch of the ulna. The joint is blocky, with a helical deviation from the median line of the block.

Shoulder joint(articulatio humeroradial)- this is the articulation of the head of the shoulder and the fossa on the head of the radius, the shape of the joint is spherical.

Proximal radioulnar joint(articulatio radioulnaris proximalis) formed by the radial notch of the ulna and the articular circumference of the radius. The shape of the joint is cylindrical. Movements in the elbow joint are possible around two mutually perpendicular axes: frontal - flexion and extension, and vertical, passing through the glenohumeral joint - pronation and supination.

The following ligaments are present in the elbow joint: the annular ligament of the radius (lig. annulare radii) in the form of a ring covers the head of the humerus; radial collateral ligament (lig. collaterale radiale) comes from the lateral epicondyle and passes into the annular ligament; ulnar collateral ligament (lig. collaterale ulnare) passes from the medial epicondyle to the medial edge of the coronoid and ulnar processes of the ulna.

Forearm joints

The bones of the forearm in their proximal and distal sections are connected using a combined joint. The proximal radioulnar joint has been discussed above.

Distal radioulnar joint(articulatio radioulnaris distalis) formed by the head of the ulna and the ulnar notch of the radius. An additional formation in the joint is the articular disc. The shape of the joint is cylindrical. Movements in the joint - pronation and supination - are possible around the vertical axis passing through the head of the radius and ulna. Tendon interosseous membrane stretched between the interosseous crests of the radius and ulna (membrana interossea antebrachii) with holes for the passage of blood vessels and nerves.

Between both bones of the forearm there is a continuous connection in the form of an interosseous membrane.

Hand joints

wrist joint(articulatio radiocarpea) is complex (Fig. 41). It is elliptical in shape of the articular surfaces. His

Rice. 41. Joints and ligaments of the hand: a - front view: 1 - distal radioulnar joint; 2 - ulnar collateral ligament of the wrist; 3 - pisi-hook ligament; 4 - pisi-metacarpal ligament; 5 - hook of the hook-shaped bone; 6 - palmar carpal-metacarpal ligaments; 7 - palmar metacarpal ligaments; 8 - deep transverse metacarpal ligaments; 9 - metacarpophalangeal joint (opened); 10 - fibrous sheath of the third finger of the hand (opened); 11 - interphalangeal joints (opened); 12 - tendon of the muscle - deep flexor of the fingers; 13 - tendon of the muscle - superficial flexor of the fingers; 14 - collateral ligaments; 15 - carpometacarpal joint of the thumb (opened); 16 - capitate bone; 17 - radiant ligament of the wrist; 18 - radial collateral ligament of the wrist;

19- palmar radiocarpal ligament;

20 - lunate bone; 21 - radius; 22 - interosseous membrane of the forearm; 23 - ulna

form the articular surface of the radius, the articular disc and the proximal row of carpal bones (scaphoid, lunate, trihedral). The articular disc separates the distal radioulnar joint from the wrist joint. Movements are possible around the frontal axis - flexion and extension, and around the sagittal axis - abduction and adduction.

Wrist joints, intercarpal jointsarticulationes intercarpales connect the bones of the wrist. These joints are reinforced by interosseous and intercarpal ligaments. (ligg. interossea et intercarpea), palmar and dorsal intercarpal (ligg. intercarpea palmaria et dorsalia).

Rice. 41. Continuation: b - frontal cut of the left wrist joint and joints of the bones of the wrist), front view: 1 - radius; 2 - wrist joint; 3 - radial collateral ligament of the wrist; 4 - mid-carpal joint; 5 - intercarpal joint; 6 - carpometacarpal joint; 7 - intermetacarpal joint; 8 - intercarpal ligament; 9 - collateral ulnar ligament of the wrist; 10 - articular disc;

11 - distal radioulnar joint;

Pisiform joint(articulatio ossis pisiformis)- this is the joint between the pisiform bone, located in the tendon of the ulnar extensor of the hand, and the triquetral bone.

Carpometacarpal joints(articulationes carpometacarpals) complex. They articulate the second row of carpal bones with the bases of the metacarpal bones. II-IV carpometacarpal joints are flat joints. They are reinforced with palmar and dorsal ligaments.

Carpometacarpal joint of thumb(articulatio carpometacarpea pollicis) formed by the trapezoid bone and the base of the I metacarpal bone; this is the saddle joint. Movements in the joint are carried out around two axes: frontal - opposition (opposition) and reverse movement (reposition) and sagittal - abduction and adduction.

Metacarpal joints(articulationes intermetacarpals) located between the bases of the II-V metacarpal bones.

Metacarpophalangeal joints(articulationes metacarpophalangeae) formed by the heads of the metacarpal bones and the pits of the bases of the proximal

phalanges of fingers. The metacarpophalangeal joints of the II-V fingers are spherical in shape. The joints are reinforced with ligaments. Movement in them is possible around the frontal axis - flexion and extension, sagittal axis - abduction and adduction; rotational movements are also possible, and in the I metacarpophalangeal joint - only flexion and extension.

Interphalangeal joints of the hand(articulationes interphalangeae manus) formed by the heads and bases of the middle phalanges, the heads of the middle and bases of the distal phalanges. In shape, these are block-shaped joints. Ligaments run along the side surfaces of the joint. Movements in the joint are possible around the frontal axis - flexion and extension.

Differences in the structure and functions of the joints of the upper limb

Differences in the shape of the joints are due to the functional features of the upper limb. So, the structure of the joints of the upper limb girdle depends on individual characteristics. In persons engaged in heavy physical labor, a costoclavicular joint appears between the 1st rib and the clavicle in place of the ligament of the same name. In individuals with highly developed muscles, full extension in the elbow joint is impossible, which is associated with excessive development of the olecranon and functional hypertrophy of the flexors of the forearm. With insufficiently developed muscles, not only full extension is possible, but also hyperextension in the joint, as a rule, in women. The mobility of the joints in women is somewhat greater than in men. Especially large is the range of motion in the small joints of the hand and fingers.

X-ray anatomy of the joints of the upper limb

On radiographs (see Fig. 28) of the upper limb, the joints are defined as gaps between the bones due to the fact that articular cartilage transmits x-rays better than bone tissue. The capsule and ligaments, as well as the cartilage, are usually not visible.

Joints of the lower limb

Joints of the girdle of the lower limb

Articulations of the pelvic bones are discontinuous and continuous. The pelvic bones have a complex ligamentous apparatus. The sacrotuberous ligament runs from the lateral edge of the sacrum and coccyx to the ischial tuberosity. (lig. sacrotuberale). sacrospinous ligament (lig. sacrospinale),

starting in the same place as the previous one, it intersects with it and attaches to the ischial spine. Both ligaments turn the greater and lesser ischial notches into foramina of the same name. (for. ischiadica majus et minus), through which muscles, blood vessels and nerves pass. The obturator foramen is closed by a fibrous obturator membrane (membrana obturatoria), excluding the upper lateral edge, where a small opening remains, passing into the obturator canal (canalis o bturatorius), through which the vessels and nerves of the same name pass.

Pubic symphysis(symphysis pubica) belongs to a special type of synchondrosis and is located in the sagittal plane. Between the surfaces of the pubic bones facing each other, covered with hyaline cartilage, there is an interpubic disc (discus interpubicus), having a small cavity.

sacroiliac joint(articulatio sacroiliaca) formed by the ear-shaped articular surfaces of the sacrum and ilium. According to the shape of the articular surfaces, the joint is flat. The articular surfaces are covered with fibrous cartilage. The joint is strengthened by strong ligaments, which almost completely eliminates movement in it.

The pelvis as a whole

In education pelvis(pelvis)(Fig. 42) the pelvic bones, the sacrum with the coccyx, and the ligamentous apparatus take part. The pelvis is divided into big(pelvis major) And small(pelvis minor). They are separated by a border line (lipea terminalis), running from the cape of the sacrum to the arcuate line of the ilium, then along the crests of the pubic bones and ending at the upper edge of the symphysis.

The small pelvis has two openings - apertures: the upper (apertura pelvis superior), bounded by the boundary line, and the lower (apertura pelvis inferior).

The structure of the pelvis has pronounced gender differences: the female pelvis is wider and shorter, the male pelvis is higher and narrower. The wings of the ilium of the pelvis of women are deployed more strongly, the entrance to the pelvic cavity is larger. The pelvic cavity in women resembles a cylinder, in men - a funnel. cape (promontory) on the pelvis of men it is more pronounced and protrudes forward. The sacrum in women is wide, flat and short, in men it is narrow, high and curved. The ischial tubercles in women are more deployed to the sides, the junction of the pubic bones forms an arc, and the lower branches of the ischial and pubic bones form a right angle. In the male pelvis, the pubic branches join to form an acute angle.

For the physiological birth act, the dimensions of the female pelvis are of great importance. The direct size of the entrance to the small pelvis - true, or gynecological, conjugate(conjugata vera, sen conjugata gynecologica) is the distance from the cape of the sacrum to the most protruding point on the posterior surface of the pubic symphysis and is 11 cm. Transverse diameter(diameter transverse) the entrance to the small pelvis is 12 cm. This is the distance between the most distant points of the boundary line. oblique diameter(diameter obliqua)- the distance between the sacroiliac joint on one side and the crests of the pubic bones on the other. The distance from the lower edge of the symphysis to the coccyx is called the direct size of the exit from the pelvis and is 9 cm. It increases to 11-12 cm during childbirth.

Joints of the free lower limb

hip joint

hip joint(articulatio coxae)(Fig. 43) is formed by the acetabulum of the pelvic bone and the head of the femur. According to the shape of the articular surfaces, the hip joint is a spherical joint of a limited type - a cup-shaped joint. Movements in it are less extensive and are possible around three mutually perpendicular axes: frontal - bending And extension, vertical - supination And pronation, sagittal - abduction And cast. In addition, circular rotation is possible. The depth of the articular cavity increases due to the cartilaginous acetabular lip (Labrum Acetabuli), bordering the edge of the acetabulum. Above the acetabular notch

Rice. 42. Connections of the bones of the girdle of the lower extremities:

a - front view: 1 - anterior longitudinal ligament; 2 - cape; 3 - iliac-lumbar ligament; 4 - anterior sacroiliac ligament; 5 - inguinal ligament; 6 - iliopectineal arch; 7 - sacrospinous ligament; 8 - fossa of the acetabulum; 9 - transverse ligament of the acetabulum; 10 - obturator membrane; 11 - medial leg; 12 - arcuate ligament of the pubis; 13 - pubic symphysis; 14 - upper pubic ligament; 15 - obturator canal; 16 - lacunar ligament; 17 - upper anterior iliac spine;

b - rear view: 1 - superior articular process of the sacrum; 2 - iliac-lumbar ligament; 3 - posterior sacroiliac ligament; 4 - supraspinous ligament; 5 - posterior sacroiliac ligament; 6 - large sciatic foramen; 7 - superficial posterior sacrococcygeal ligament; 8 - sacrospinous ligament; 9 - small sciatic foramen; 10 - sacrotuberous ligament; 11 - obturator opening; 12 - deep posterior sacrococcygeal ligament; 13 - pubic symphysis; 14 - ischial tubercle; 15 - ischial spine; 16 - superior posterior iliac spine

Rice. 43. Hip joint, right:

a - a frontal cut opened the cavity of the hip joint: 1 - pelvic bone; 2 - articular cartilage; 3 - joint cavity; 4 - ligament of the femoral head; 5 - acetabular lip; 6 - transverse ligament of the acetabulum; 7 - ligament - circular zone; 8 - large skewer; 9 - head of the femur; b - ligaments of the joint, front view: 1 - lower anterior iliac spine; 2 - iliac-femoral ligament; 3 - joint capsule; 4 - pubic-femoral ligament; 5 - obturator canal; 6 - obturator membrane; 7 - small spit; 8 - femur; 9 - large skewer

the strong transverse ligament of the acetabulum is thrown (lig. transversum acetabuli). Inside the joint there is an intra-articular ligament of the femoral head (lig. capitis femoris).

The capsule of the hip joint starts from the edges of the acetabulum and is attached on the epiphysis of the femur in front to the intertrochanteric line behind, not reaching the intertrochanteric crest. Fibrous fibers of the capsule form a circular zone around the neck of the femur (zona orbicularis). The joint capsule is reinforced with extra-articular ligaments: iliofemoral ligament (lig. iliofemorale) starts from the lower anterior iliac spine and attaches to the intertrochanteric line; ischiofemoral ligament (lig. ischiofemoral) goes from the body and tubercle of the ischium to the capsule; pubofemoral ligament (lig. pubofemorale) runs from the superior branch of the pubis to the lesser trochanter.

Knee-joint

Knee-joint(articulatio genus)(Fig. 44) has the largest articular surfaces; it's a complex joint. The condyles of the femur and tibia and the patella take part in its formation. The shape of the articulating surfaces of the knee joint is condylar (articulatio bicondylaris). Movements occur around two axes: frontal - bending And extension and vertical (with a half-bent knee) - pronation And supination. Inside the joint cavity are the medial and lateral menisci (meniscus medialis et lateralis), made up of fibrous cartilage. Anteriorly, both menisci are connected by the transverse ligament of the knee (lig. transversum genus). Inside the fibrous capsule of the joint lie the anterior and posterior cruciate ligaments. (lig. cruciatum anterius et posterius). The anterior one starts from the lateral condyle, goes down and inward, attaches to the anterior intercondylar field. The posterior cruciate ligament extends outward from the medial condyle of the femur and inserts into the posterior condylar field of the tibia. Joint capsule reinforced with ligaments: peroneal collateral ligament (lig. collaterale fibulare) goes from the external condyle of the femur to the head of the fibula; tibial collateral ligament (lig. collaterale tibiale) passes from the internal condyle of the femur to the condyle of the tibia; oblique popliteal ligament (lig. popliteum obliquum) comes from the internal condyle of the tibia

Rice. 44. Knee joint: a - front view: 1 and 4 - lateral and medial supporting ligaments of the patella; 2 - tendon of the quadriceps femoris; 3 - patella;

5- ligament of the patella;

b - after opening the joint cavity: 1 - pterygoid fold; 2 - lateral meniscus; 3 - fibrous membrane of the joint capsule; 4 - synovial membrane; 5 - suprapatellar bag; 6 - posterior i7 - anterior cruciate ligaments; 8 - subpatellar synovial fold; 9 - medial meniscus; 10 - patella;

c - sagittal cut of the joint in the sagittal plane: 1 - meniscus; 2 - synovial bag under the posterior muscles of the thigh; 3 - suprapatellar bag; 4 - prepatellar bag (subcutaneous); 5 - patella; 6 - subpatellar fat body (anterior continuation of the pterygoid folds); 7 - ligament of the patella; 8 - subpatellar subcutaneous bag; 9 - subpatellar deep bag

bones upward and laterally to the joint capsule; arcuate popliteal ligament (lig. popliteum a rcuatum) originates from the lateral condyle of the femur and is part of the oblique ligament. Patella ligament (lig. patellae) comes from the top of the patella and is attached to the tuberosity of the tibia. On the sides of this ligament are the medial and lateral supporting ligaments of the patella. (retinaculi patellae mediate et laterale).

The synovial membrane of the knee joint covers the cruciate ligaments, forming folds with layers of fatty tissue. The most strongly developed pterygoid folds (plicae alares). The synovial membrane contains villi.

The membrane itself forms 9 inversions: an unpaired anterior-superior median and 8 paired ones - 4 each in front and behind: anterior superior and anteroinferior, posterior superior and posterior inferior (medial and lateral). A number of mucous bags are isolated in the knee joint (Fig. 45): subcutaneous prepatellar (b. subcutaneaprepatellaris), subfascial prepatellar (b. subfascialis prepatellaris), subtendonal prepatellar (b. subtendinea prepatellaris), deep sub-

Rice. 45. Synovial (mucous) bags of the knee joint filled with dye (photo from the preparation): 1 - fragments of the joint capsule; 2 - suprapatellar bag; 3 - tendon of the quadriceps femoris; 4 - patella; 5 - ligament of the patella; 6 - joint cavity surrounded by a synovial membrane; 7 - medial meniscus; 8 - tibial collateral ligament; 9 - tendon of one of the posterior muscles of the thigh; 10 and 11 - bags under the posterior muscles of the thigh and lower leg

patellar (b. infrapatellaris profunda), communicating with the joint cavity. On the back surface of the joint, the bags are located under the tendons of the muscles.

Leg joints

Both bones of the lower leg in the proximal part form an articulation - tibiofibular joint(articulatio tibiofibularis), having a flat shape.

Foot joints

Ankle joint(articulatio talocruralis) formed by the articular surfaces of the distal ends of the leg and the block of the talus (Fig. 46). The joint is block-shaped in shape, movements in it are possible around the frontal axis - flexion and extension. The joint capsule is attached to the edge of the articular surfaces of the bones. From the sides, the capsule is reinforced with ligaments: medial (deltoid) (lig. collaterale mediale; lig. deltoideum), anterior and posterior talofibular (ligg. talofibulares anterius et posterius) and calcaneofibular (lig. calcaneofibulare).

Intertarsal joints(articulationes intertarseae) formed between adjacent bones of the tarsus. These include talocalcaneal-navicular joint(articulatio talocalcaneonavicularis),transverse tarsal joint(articulatio tarsi transversa),calcaneocuboid joint(articulatio calcaneocuboidea),cuneiform joint(articulatio cuneonavicularis).

Tarsus-metatarsal joints(articulationes tarsometatarsales) formed by the bones of the tarsus and metatarsus. They are flat and include the following joints: between the medial sphenoid and I metatarsal bones, between the intermediate and lateral sphenoid bones and II-III metatarsal bones, between the cuboid bone and IV-V metatarsal bones. The joints are reinforced with strong plantar and dorsal ligaments.

Intermetatarsal joints(articulationes intermetatarsales) located between the lateral surfaces of the four metatarsal bones facing each other; according to the shape of the articulating surfaces, these are flat joints.

Metatarsophalangeal joints(articulationes metatarsophalangeae) formed by the heads of the metatarsal bones and the bases of the I-V phalanges. According to the shape of the articular surfaces, these joints are spherical, but their mobility is limited.

Rice. 46. Foot joints:

a - top view of the foot: 1 - interphalangeal joints; 2 - metatarsophalangeal joints; 3 - wedge-shaped bones of the tarsus; 4 - cuboid bone; 5 - calcaneus;

6 - talus with a block - the articular surface of the ankle joint;

7- transverse joint of the tarsus; 8 - navicular bone; 9 - tarsal-metatarsal joints;

b - view of the foot from the medial side: 1 - dorsal tarsal-metatarsal ligaments; 2 - ligaments between the bones of the tarsus (sphenoid-navicular); 3 - collateral medial ligament (deltoid); 4 - long plantar ligament; 5 - calcaneonavicular ligament

Interphalangeal joints of the foot(articulationes interphalangeae pedis) located between the individual phalanges of the fingers and have a block shape.

Movements in the joint are performed around the frontal axis - flexion and extension.

Differences in the structure and functions of the joints of the lower limb

The joints of the lower extremity differ significantly in the size and shape of the articular surfaces, as well as in the strength of the ligamentous apparatus. In adults, the ankle joint has greater mobility towards the sole, and in children - towards the rear. The child's foot is more supinated. When a child begins to walk, he does not rely on the entire foot, but on its outer edge. The shape of the foot may depend on the profession. In people engaged in heavy physical labor, the foot is wide and short; in persons not engaged in hard work, it is narrow and long. The foot has an arched structure, performing support and spring functions. There are 2 forms of foot: vaulted and flat. The arched structure of the foot provides a springy effect when walking and is supported by the ligaments of the sole, in particular the long plantar ligament (see Fig. 46, b). The flat shape causes the development of a pathological condition called flat feet.

X-ray anatomy of the joints of the bones of the lower limb

On radiographs of the joints of the lower limb, bone articular surfaces delimited by the joint space are determined. The thickness and transparency of the latter, depending on the state of the cartilage, may change with age.

Questions for self-control

1. With the help of what joints is the clavicle connected to the bones of the upper limb? Describe these joints.

2. What movements are possible in the shoulder joint?

3. How is the elbow joint arranged? Give a description of each of the joints that make it up.

4. How is the wrist joint arranged? What movements are possible in this joint?

5. What is the carpometacarpal joint of the thumb formed by? What movements are carried out in this joint?

6. What types of connections are there in the joints of the pelvic bones? Describe these compounds.

7. List the dimensions of the female pelvis. What is the significance of these sizes in women?

8. List the extracapsular and intracapsular ligaments of the knee joint. How do these ligaments affect joint movement?

9. How is the ankle joint built? What movements are possible in this joint? Name the ligaments that strengthen it.

10. List the intertarsal joints.

SKULL JOINTS

The bones of the skull are articulated in different ways: the bones that form the vault, through fibrous joints - sutures, and the base of the skull - with the help of cartilaginous joints, synchondroses of the skull.

The lower jaw is attached to the temporal bones through the temporomandibular joints.

Skull as a whole

As mentioned above, the skull is divided into cerebral and facial. In the first, a vault and a base are distinguished. On the vault, on the side, on each side there is temporal fossa, serving as a place of fixation of the temporal muscle, and in front of the elevation - frontal tubercle.

At the base of the skull, which looks like a thick plate with a complex relief, there are outer base of the skull(basis cranii externa), facing down towards the neck, and inner base of the skull(basis cranii interna), which together with the cranial vault forms cranial cavity(cavitas cranii)- seat of the brain.

Both the outer and inner base of the skull is permeated with a large number of holes, channels, crevices, in which the vessels and nerves that connect the brain with the body as a whole are placed.

On the border of the base of the skull with the facial skull there are pits that are important in practical terms: infratemporal, located immediately below the temporal fossa fornix, and pterygopalatine- continuation of the infratemporal in depth, in the medial direction.

The bones of the facial skull, together with some bones of the base of the skull, form eye socket(orbita) And bony nasal cavity(cavitas nasalis ossea)- the location of the eye and related structures and the olfactory organ, respectively. Bones of the facial skull: upper and lower jaws, palatine bones are involved in the formation oral cavity(cavitas oris).

Joints unite the bones of the skeleton into a single whole. More than 180 different joints help a person move. Together with bones and ligaments, they are referred to as the passive part of the motor apparatus.

Joints can be compared to hinges, the task of which is to ensure smooth sliding of bones relative to each other. In their absence, the bones will simply rub against each other, gradually breaking down, which is a very painful and dangerous process. In the human body, the joints play a triple role: they help maintain the position of the body, participate in the movement of body parts relative to each other, and are organs of locomotion (movement) of the body in space.

Each joint has various elements that facilitate the mobility of some parts of the skeleton and ensure strong conjugation of others. In addition, there are non-osseous tissues that protect the joint and soften interosseous friction. The structure of the joint is very interesting.

The main elements of the joint:

joint cavity;

Epiphyses of the bones that form the joint. The epiphysis is a rounded, often expanded, terminal section of a tubular bone that forms a joint with an adjacent bone by articulating their articular surfaces. One of the articular surfaces is usually convex (located on the articular head), and the other is concave (formed by the articular fossa)

Cartilage is the tissue that covers the ends of bones and cushions their friction.

The synovial layer is a kind of bag that lines the inner surface of the joint and secretes synovium, a fluid that nourishes and lubricates the cartilage, since the joints do not have blood vessels.

The joint capsule is a sleeve-like, fibrous layer enveloping the joint. It gives the bones stability and prevents their excessive displacement.

The menisci are two hard cartilages shaped like crescents. They increase the area of contact between the surfaces of two bones, as, for example, the knee joint.

Ligaments are fibrous formations that strengthen interosseous joints and limit the amplitude of bone movement. They are located on the outside of the joint capsule, but in some joints they are located inside for better strength, such as round ligaments in the hip joint.

The joint is an amazing natural mechanism of movable conjugation of bones, where the ends of the bones are connected in the articular bag. bag outside is a fairly strong fibrous tissue - it is a dense protective capsule with ligaments that help control and hold the joint, preventing displacement. From the inside, the articular bag is synovial membrane.

This membrane produces synovial fluid - lubrication of the joint, viscoelastic consistency, which even in a healthy person is not so much, but it occupies the entire joint cavity and is able to perform important functions:

1. It is a natural lubricant that gives the joint freedom and ease of movement.

2. It reduces the friction of the bones in the joint, and thus protects the cartilage from abrasion and wear.

3. Acts as shock absorber and shock absorber.

4. Works as a filter, providing and maintaining cartilage nutrition, while protecting it and the synovial membrane from inflammatory factors.

synovial fluid A healthy joint has all of these properties, largely due to hyaluronic acid found in the synovial fluid, as well as in cartilage tissue. It is this substance that helps your joints to fully perform their functions and allows you to lead an active life.

If the joint is inflamed or diseased, then more synovial fluid is produced in the synovial membrane of the joint capsule, which also contains inflammatory agents that increase swelling, swelling, and pain. Biological inflammatory agents destroy the internal structures of the joint.

The ends of the joints of the bones are covered with an elastic thin layer of smooth substance - hyaline cartilage. Articular cartilage does not contain blood vessels or nerve endings. The cartilage, as has been said, receives its nourishment from the synovial fluid and from the bony structure beneath the cartilage itself, the subchondral bone.

Cartilage basically performs the function of a shock absorber - it reduces pressure on the mating surfaces of the bones and ensures smooth sliding of the bones relative to each other.

Functions of cartilage

1. Reduce friction between joint surfaces

2. Absorb shocks transmitted to the bone during movement

Cartilage is made up of special cartilage cells - chondrocytes and intercellular substance matrix. The matrix consists of loosely located connective tissue fibers - the main substance of cartilage, which is formed by special compounds - glycosaminoglycans.
Namely, connected by protein bonds, glycosaminoglycans that form larger cartilage structures - proteoglycans - are the best natural shock absorbers, since they have the ability to restore their original shape after mechanical compression.

Due to the special structure, the cartilage resembles a sponge - absorbing fluid in a calm state, it releases it into the articular cavity under load and thus, as it were, additionally "lubricates" the joint.

Such a common disease as arthrosis upsets the balance between the formation of new and the destruction of the old building material that forms cartilage. Cartilage (the structure of the joint) changes from strong and elastic to dry, thin, dull and rough. The underlying bone thickens, becomes more uneven, and begins to grow away from the cartilage. This contributes to the restriction of movement and causes deformation of the joints. There is a seal of the joint capsule, as well as its inflammation. The inflammatory fluid fills the joint and begins to stretch the capsule and joint ligaments. This creates a painful feeling of stiffness. Visually, you can observe an increase in the joint in volume. Pain, and subsequently deformation of the surfaces of the joints in arthrosis, leads to tight joint mobility.

Joints are distinguished by the number of articular surfaces:

simple joint (lat. articulatio simplex) - has two articular surfaces, for example, the interphalangeal joint of the thumb;
complex joint (lat. articulatio composita) - has more than two articular surfaces, for example, the elbow joint;
complex joint (lat. articulatio complexa) - contains intra-articular cartilage (meniscus or disc), dividing the joint into two chambers, for example, the knee joint;
combined joint - a combination of several isolated joints located separately from each other, for example, the temporomandibular joint.

The shape of the articular surfaces of the bones is compared with geometric figures and, accordingly, the joints are distinguished: spherical, ellipsoid, block-shaped, saddle-shaped, cylindrical, etc.

Joints with movement

. shoulder joint: the articulation that provides the greatest range of motion of the human body is the articulation of the humerus with the scapula using the glenoid cavity of the scapula.

. elbow joint: connection of the humerus, ulna and radius bones, allowing you to make a rotational movement of the elbow.

. Knee-joint: a complex joint that provides flexion and extension of the leg and rotational movements. The femur and tibia are articulated at the knee joint - the two longest and strongest bones, which, together with the patella, located in one of the tendons of the quadriceps muscle, are pressed by almost the entire weight of the skeleton.

. hip joint: connection of the femur with the bones of the pelvis.

. wrist joint: formed by several joints located between numerous small flat bones connected by strong ligaments.

. Ankle joint: the role of ligaments is very important in it, which not only provide movement of the lower leg and foot, but also support the concavity of the foot.

There are the following main types of movements in the joints:

movement around the frontal axis - flexion and extension;
movements around the sagittal axis - adduction and abduction of movement around the vertical axis, that is, rotation: inwards (pronation) and outwards (supination).

The human hand contains: 27 bones, 29 joints, 123 ligaments, 48 nerves and 30 named arteries. Throughout life, we move our fingers millions of times. The movement of the hand and fingers is provided by 34 muscles, only when moving the thumb, 9 different muscles are involved.

shoulder joint

It is the most mobile in humans and is formed by the head of the humerus and the glenoid cavity of the scapula.

hip joint

This joint is under heavy load, so it is not surprising that its lesions occupy the first place in the general pathology of the articular apparatus.

Knee-joint