The main elements of the joint and their functions. 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 structured the same. They differ only in shape, nature of movement and the number of articulating bones.

Joints simple and complex

Classification of joints by anatomical structure

According to their anatomical structure, joints are divided into:

Simple. The joint consists of two bones. An example is the shoulder or interphalangeal joints.
Complex. A joint is formed by 3 or more bones. An example is the elbow joint.
Combined. Physiologically, the two joints exist separately, but function only in pairs. This is how the temporomandibular joints are designed (it is impossible to lower only the left or right side 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 more precisely the principle of operation, read the article with beautiful illustrations about the Structure of the human spine.
Complex. The joint space 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 a recess of suitable size. The radioulnar joint is a cylindrical joint.
Block-shaped. 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 the groove like a key to a lock. This is how the ankle joints are designed.
A special case of trochlear joints is the helical joint. Its distinctive feature is the spiral arrangement of the groove. An example is the shoulder-elbow joint.
Ellipsoidal. One articular surface has an ovoid convexity, the second has an oval notch. These are the metacarpophalangeal joints. When the metacarpal sockets rotate relative to the phalangeal bones, complete bodies of rotation are formed - ellipses.
Condylekov. Its structure is similar to the ellipsoidal one, but its articular head is located on a bony protrusion - the condyle. An example is the knee joint.

Saddle-shaped. In its form, the joint is similar to two nested saddles, the axes of which intersect at right angles. The saddle joint includes the carpometacarpal joint of the thumb, which among all mammals is present only in humans.
Spherical. The joint articulates the ball-shaped head of one bone and the cup-shaped notch of the other. A representative of this type of joint is the hip. When the socket of the pelvic bone rotates relative to the femoral head, a ball is formed.
Flat. The articular surfaces of the joint are flattened, the range of motion is insignificant. The flat one includes the lateral atlantoaxial joint, connecting the 1st and 2nd cervical vertebrae, or lumbosacral joints.
A change in 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 shift relative to each other. This condition is called spondyloarthrosis. Over time, the deformity becomes fixed and develops into a permanent curvature of the spine. Instrumental examination methods (computed tomography, radiography, MRI of the spine) help to detect the disease.

Division by nature of movement

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

uniaxial (these include block-shaped),
biaxial (ellipsoidal, condylar and saddle-shaped),
multi-axial (spherical and flat).

Summary table of joint movements

Number of axes Joint shape Examples

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

One trochlear ulna

Two Ellipsoid Atlanto-occipital (connects the base of the skull with the upper cervical vertebra)

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 joints:

Movement around the frontal (horizontal) axis - flexion (flexio), i.e. decreasing the angle between the articulating bones, and extension (extensio), i.e. increasing this angle.
Movements around the sagittal (horizontal) axis - 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): inward (pronatio) and outward (supinatio).
Circular movement (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 - the figure of a cone.

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, and compound bursa. In addition, the structure of the knee contains a meniscus (it is a cartilaginous formation that optimizes the alignment of the articular surfaces and acts as 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 buffer 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 internal synovial membrane performs the function of secreting synovial fluid. The outside of the bag is covered with a fibrous membrane, and the inside is lined with a synovial membrane. The outer layer is stronger and thicker than the inner one, the fibers are directed longitudinally.

As for the synovial cavity, it is a closed, sealed, slit-shaped space that is bounded by the articular surfaces of the bones and the synovial membrane. If we look at the knee, then in the synovial cavity there is a meniscus.

Additional articular components are muscles and tendons, ligaments, nerves and vessels that directly surround the joint, provide its nutrition and innervation. They are also called joint tissues. These tissues provide mobility and perform a strengthening function. It is through them that microvasculature vessels pass, which nourish 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 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 joint 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 axis.

2.1.1. In the form of a cylinder. An example is the atlantoaxial joint of the spine.

2.1.2. Blocky (block-shaped). An example is the interphalangeal joints.

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

2.2. With two axes.

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 finger.

2.3. Having more than two axes.

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 of this is the intervertebral joint.

Before talking about these diseases, I would like to immediately say that they are a serious pathology. It should only be treated by qualified specialists! Self-medication in this case is strictly contraindicated, because it can only aggravate the course of an already serious and slow-onset disease.

As for joint diseases, there are quite a lot of them now identified. Below are the most common ones.

Some diseases

Hypermobility

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

The cause of excessive extensibility of ligaments is disturbances in the structure of collagen fibers, as a result, the strength of collagen decreases, and, accordingly, it becomes more elastic and more susceptible to stretching. Scientists have established the hereditary nature of the transmission of this condition, but the mechanism of development is not fully understood.

Increased mobility is detected most often in young women.

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Anatomical features

Human joints are the basis of every body movement. 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 immobile, 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;
shapes of 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 structured? It looks like a bag of two layers that surrounds the junction of several bones. The bursa seals the cavity and promotes the production of synovial fluid. It, in turn, acts as a shock absorber for bone movements. Together they perform three main functions of the joints: they help stabilize the body position, are part of the process of movement in space, and ensure the movement of parts of the body in relation to each other.

Basic elements of a joint

The structure of human joints is complex and is divided into the following basic elements: cavity, capsule, surface, synovial fluid, cartilage, ligaments and muscles. We'll talk briefly about each below.

The joint 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 from a fibrous membrane, but inside it has a thin synovial membrane (a source of synovial fluid).
Articular surfaces have a special shape, one of them is convex (also called the head), and the second is pit-shaped.

Synovial fluid. Its main function is to lubricate and moisturize surfaces; it also plays an important role in fluid exchange. It is a buffer zone during various movements (pushing, jerking, squeezing). Provides both sliding and divergence of bones in the cavity. A reduction in the amount of synovium leads to a number of diseases, bone deformations, loss of a person’s ability to perform normal physical activities and, as a result, even disability.
Cartilage tissue (thickness 0.2 - 0.5 mm). The surfaces of the bones are covered with cartilage tissue, the main function of which is shock absorption during walking and sports. The anatomy of cartilage is composed of connective tissue fibers that are filled with fluid. This, in turn, nourishes the cartilage when it is at rest, and during movement it releases fluid to lubricate the bones.
Ligaments and muscles are auxiliary parts of the structure, but without them the normal functionality of the entire body is impossible. With the help of ligaments, bones are fixed without interfering with movements of any amplitude due to their elasticity.

The inert 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 next to the process of the scapula, it reduces the range of motion of the arm.

Classification and types

In the process of development of the human body, way of life, mechanisms of interaction between man and the external environment, the need to perform various physical actions, various types of joints were obtained. The classification of joints and its basic principles are divided into three groups: the number of surfaces, the shape of the end of the bones, and functionality. We'll 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 the bag. This type includes shoulder, knee, hip and others. There is also a so-called facet joint. Its main characteristic is the limitation of rotation to 5 degrees and tilt to 12 degrees. The function also consists of limiting the mobility of the spine, which helps 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 a connection between two bones (interphalangeal bones).
Complex – a connection of more than two bones (elbow). The characteristics of such a connection imply the presence of several simple bones, while the functions can be implemented separately from each other.
Complex joint - or two-chamber, which contains cartilage that connects several simple joints (lower jaw, radioulnar). Cartilage can separate the 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 shapes of the joints and the ends of the bones have the shape 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 joints according to the shape of their 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 - a cylinder-shaped joint (transverse), one axis of rotation, but in the frontal plane, perpendicular to the connected bones. Characteristic movements are flexion and extension.
Helical is a variation of the previous type, but the axes of rotation of this form are located at an angle other than 90 degrees, forming helical rotations.
Ellipsoidal - 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, abduct-addite. The ligaments are perpendicular to the axes of rotation.
Condylar is a type of ellipsoidal. The main characteristic is the condyle (a rounded process on one of the bones), the second bone is in the shape of a depression, and can differ significantly in size from each other. The main axis of rotation is represented by the frontal one. The main difference from the block-shaped one is the strong difference in the size of the surfaces, from the ellipsoidal one - 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 the trochlear one) or in different capsules (similar to the ellipsoidal one).

Saddle-shaped - formed by connecting two surfaces as if “sitting” on each other. One bone moves lengthwise, while the second moves across. Anatomy involves rotation around perpendicular axes: flexion-extension and abduction-adduction.
Ball-and-socket joint - the surfaces are shaped like balls (one convex, the other concave), due to which people can make circular movements. Basically, rotation occurs along three perpendicular axes, the intersection point being the center of the head. The peculiarity is a very small number of ligaments, which does not interfere with circular rotations.
Cup-shaped - the anatomical appearance involves a deep depression of one bone that covers most of the area of the head of the second surface. As a result, there is less free mobility compared to the spherical one. Necessary for greater joint stability.
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 that are closely connected to each other. Anatomy: inactive, surfaces are represented by tight capsules, non-elastic short ligaments.

By nature of movement

Due to their physiological characteristics, joints perform many movements along their axes. In total, there are three types in this group:

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
	Block-shaped	Interphalangeal joints of the fingers
	Helical	Humeral-ulnar
Biaxial	Ellipsoidal	Radiocarpal
	Condylar	Knee
	Saddle	Carpometacarpal joint of the thumb
Multi-axis	Globular	Brachial
	Cup-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.
Abduction and adduction.
Circular movements (surfaces move between axes, the end of the bone draws a circle, and the entire surface draws the shape of a cone).
Sliding movements.
Removal from one another (for example, peripheral joints, distance of fingers).

The degree of mobility depends on the difference in the size of the surfaces: the larger the area of one bone over another, the greater the range of movement. Ligaments and muscles can also inhibit 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 articular cavity of the scapula.

The articular surface of the scapula is surrounded by a ring of fibrocartilage - the so-called articular lip. The tendon of the long head of the biceps brachii muscle passes through the joint cavity. The shoulder joint is strengthened by the powerful coracohumeral ligament and surrounding muscles - deltoid, subscapularis, supra- and infraspinatus, teres major and minor. The pectoralis major and latissimus dorsi muscles also take part in shoulder movements.

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

The shoulder joint is capable of movement around 3 axes. Flexion is limited by the acromion 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 upper limb belt (when the sternoclavicular joint is included) - up to 180°. Abduction stops when the greater tuberosity of the humerus rests on the coracoacromial ligament. The spherical shape of the articular surface allows a person to raise his arm, move it back, and rotate the shoulder along with the forearm and 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 formation.

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 intraarticular ligament of the femoral head, as well as the transverse ligament acetabulum, which surrounds the neck of the femur. From the outside, the powerful iliofemoral, pubofemoral and ischiofemoral ligaments are woven into the capsule.

The blood supply to this joint is through the circumflex femoral arteries, branches of the obturator and (variably) 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. Lymphatic drainage occurs in 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 movements 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 experiences a lot of stress, so it is not surprising that its lesions occupy first place in the general pathology of the articular apparatus.

Knee-joint

One of the largest and most complex human joints. It is formed by 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 fibular and tibial collateral ligaments, the oblique and arcuate popliteal ligaments, the patellar ligament, and the medial and lateral suspensory ligaments of the patella. The intra-articular ligaments include the anterior and posterior cruciate ligaments.

The joint has many auxiliary elements, such as menisci, intra-articular ligaments, synovial folds, and bursae. Each knee joint has 2 menisci - the outer and the inner. The menisci look like crescents and play 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 bursae, some of which communicate with the joint cavity.

Everyone had to admire the performances of artistic gymnasts and circus performers. People who are able to climb into small boxes and bend unnaturally are said to have gutta-percha joints. Of course, this is not true. The authors of The Oxford Handbook of Body Organs assure readers that “their joints are phenomenally flexible”—medically known as 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 carried forward by raising the hip.

According to the World Health Organization, every 7th person on the planet suffers from joint pain. Between the ages of 40 and 70 years, joint diseases are observed in 50% of people and in 90% of people over 70 years of age.
Based on materials from www.rusmedserver.ru, meddoc.com.ua

7 Early Signs of Arthritis

8 Ways to Destroy Your Knees

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Simple and complex joints

The simple joint got its name, as you might guess, because of the simplicity of its 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 socket of the scapula are connected by a special tissue. A complex design will consist of 3 simpler structures that are united by a common capsule. For example, the elbow joint is complex because it has the surfaces of three bones:

brachial;
elbow;
ray.

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

Geometry plays a special role in anatomy, because many parts of the body get their names due to their similarity to one or another geometric figure. When dividing various forms of human joints into groups, associations of the similarity of body elements with geometric shapes were also used. For example, from the name “ball and socket joint” you can already get an idea of its shape. This element is capable of moving in a circle and is considered the most free. The ball and socket joint is characterized by increased mobility, thanks to which a person can carry out circular movements.

The spherical nature of this design allows people to 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 ensuring rotational movements of body parts. The cylindrical joint is found in the first and second cervical vertebrae and is present where the heads of the radius and ulna meet each other. The cylindrical joint belongs to the category of structures with one axis of movement; 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 movement. It is more durable and is located in the ankle. The interphalangeal joints are also block-shaped.

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

The flat design sits on the wrist. It is distinguished by its simplest form and small number of movements. It is called “flat” because it consists of flat bone surfaces, 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 increases significantly.

Different surfaces and configurations

The names of joints have the property of indicating what parts the biomechanical elements of the body consist of. Joints are discontinuous connections of bones that contain cartilage-covered surfaces and capsules.

They have cavities where synovial fluid is located, a thick, elastic mass that washes it. There are not only different forms, but also elements of such structures. Their disks may be present 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 basic elements remain the same.

When it comes to the synovial joint, a discussion of the treatment of musculoskeletal diseases often begins. Its peculiarity is the bag, where the ends of the bones are located. Synovial fluid is found in this sac. Most forms of such structures in the human body are synovial. It is the synovial fluid that prevents the joints from wearing out when they move along the axis of rotation. If the synovial fluid stops being 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 joint tissue (and they usually develop against the background of impaired metabolism), they are followed by various types of their diseases.

Functions performed by joints

There is an anatomical classification of joints depending on the 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;
elbows;
axillary;
vertebrates;
carpal;
hip;
sternoclavicular;
sacroiliac;
temporomandibular;
knee

The anatomical table provides a more complete classification of them (Fig. 1, 2). The functioning of joint tissue is directly affected by the elements it connects. For example, intervertebral joints have limited movement because the spinal discs are located between them. The subtalar joint is located between the talus and calcaneus bones. Its exact location is their posterior section. It is considered one of the areas of the body that are significantly susceptible to dislocation. In terms of the number of dislocations, this element is in 3rd place after dislocations that affect the Lisfranc joint. It is located transversely.

The last of them is the tarsometatarsal, which, located in the middle part of the foot, has specific features of the anatomical structure. The Lisfranc joint does not have a ligament between the bases of the first and second metatarsal bones; it belongs to the category of tarsometatarsal analogues and crosses the foot in its middle part. The Lifranc joint belongs to the category of flat analogues 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, is the Chopart joint. It is considered more durable, this property is due to the peculiarities of its anatomical structure. In a cross section, Chopara (tarsal-transverse) resembles the shape of the letter S.

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 ligament.

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 forms the lower part of the ankle joint. As a legacy from the world of mammals, humans have 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 common to horses, cats, dogs and other species of animals. Many people believe that people have it. However, in humans it is absent, but in the course of evolution, people have developed its replacement - the heel analogue. The latter has a similar set of functions to the hock joint and is closely related to the functioning of the human musculoskeletal system. It's quite complex. It includes 6 bones of different 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 joint is most often affected by arthritis, a disease that is also common in humans. In the process of man'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 treat 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 tissue. It is used to prepare broths, which are recommended for people suffering from fracture-dislocations. The fetlock joint is widely used in the manufacture of medicines.

Peripheral joints were inherited by humans as a legacy of the animal world. They are no less important than the central joints. Elderly people most often suffer from damage to peripheral joints by various arthritis, which significantly worsens their quality of life. Facet joints are most often called intervertebral joints; this group helps the spine to be flexible and mobile. This model is also present in animals. In them, like in humans, it has a relatively wide articular capsule. If it is disturbed, a person begins to experience pain in the spine. Painful symptoms affect the neck, thoracic, and lumbar regions. The facet joint gets its name from the unusual shape of its processes. No less interesting is their location in the body - on both sides of the spinal column. The facet, also called the facet, makes the spine so flexible and mobile. Various movements occur between its vertebrae.

Treatment of diseases

The occipital joint is responsible for connecting the skull to the spine. Modern medicine defines this category as the 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 joints; it connects bone tissues of different densities. 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 it, a person can tilt their head forward. If the occipital component is damaged, head movements become limited. Such structures are vulnerable, and in cases of injury 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, humanity uses various achievements of scientific and technological progress. Titanium alloy does not cause rejection by the human body, which makes it possible to perform joint replacement. The titanium element is practically no different from the natural one, but it is more durable and will allow you to maintain joint mobility in cases where tissue destruction occurs.

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

Joint- the place where human bones are connected. Joints are essential for the mobility of bone joints and they also provide mechanical support.

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

The articular surfaces have a covering consisting of hyaline or fibrous articular cartilage, the thickness of which ranges from 0.2 to 0.5 mm. Smoothness is achieved through constant friction, with the cartilage acting as a shock absorber.

The joint capsule (articular capsule) 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 tightly closes 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 located longitudinally. In some cases, the joint capsule is connected by ligaments. The inner layer of the joint capsule consists of a synovial membrane, the villi of which produce synovial fluid, which provides hydration to the joint, reduces friction and nourishes the joint. This part of the joint has the most nerves.

Joints are surrounded by periarticular tissues, which include muscles, ligaments, tendons, blood vessels and nerves.

Joint ligaments They are made 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 located inside, providing additional strength.

Blood supply to 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 are innervated, with the exception of hyaline cartilage.

Joints are classified functionally and structurally.

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

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

There are three types of joints according to structural classification:

Fibrous joints- have dense regular connective tissue rich in collagen fibers.
Cartilaginous joints- connections are formed by cartilage tissue.
Synovial joints- the bones in this type of joint have cavities and are connected by dense irregular connective tissue, forming an articular capsule, which usually has additional ligaments.

The functional classification of joints divides joints into the following types:

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

Diarthrotic joints- joints that allow free movement of joints. These joints include the shoulder joint, hip joint, elbow joint and others. These joints have a synovial joint. In this case, diarthrosis joints are divided into six subgroups depending on the type of movement: ball-and-socket joints, nut-shaped (cup-shaped) joints, block-shaped (hinged) joints, rotary 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 multi-axis joints. Joints are also divided into one, two and three degrees of freedom. Joints are also 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, joints are divided into simple and complex, it all depends on the number of bones that participate in the structure of the joint.

Simple joint- has two movable surfaces. Simple joints include the shoulder joint and the hip joint.
Complex joint- a joint that has three or more movable surfaces. This joint includes the wrist joint.
Compound joint- this joint has two or more movable surfaces, as well as an articular disc or meniscus. Such a joint may include the knee joint.

Anatomically, 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 diseases are called arthropathy. When a joint disorder is accompanied by inflammation of one or more joints it is called arthritis. Moreover, when several joints are involved in the inflammatory process, the disease is called polyarthritis, and when one joint becomes inflamed it’s called monoarthritis.

The main cause of disability in people over 55 years of age is arthritis. Arthritis comes in several forms, each caused by different causes. The most common form of arthritis is osteoarthritis or degenerative joint disease that occurs as a result of joint injury, infection, or old age. Also, according to research, it has become known that improper anatomical development is also a cause of 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 a 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 and 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 is observed 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 disorder is associated with a structural change in collagen. It loses strength and becomes more elastic, which leads to partial deformation. This disorder is believed to be hereditary.

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Types of human joints

They can be classified by functionality:

A joint that does not allow movement is known as synarthrosis. Skull sutures and gomphos (the connection of the teeth to the skull) are examples of synarthrosis. The connections between bones are called syndesmoses, between cartilages - synchordroses, and bone tissue - synthososes. Synarthrosis is formed using connective tissue.

Amphyarthrosis allows slight movement of the connected bones. Examples of amphiarthrosis are 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 from which they are composed):

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

Human cartilaginous joints consist of a group of cartilages that connect the bones together. Examples of such joints would be the joints between the ribs and costal cartilage, and between the intervertebral discs.

The most common type, a synovial joint, is a fluid-filled space between the ends of the connected bones. It is surrounded by a capsule of tough, 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 ellipsoidal, trochlear, saddle and socket joints.

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

Locking joints, such as the human elbow and knee, limit movement in only one direction so that the angle between the bones can be increased or decreased. Restricted 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 bone and the trapezium bone, allow the bones to rotate 360 degrees.

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

Some synovial types of human joints need to be considered separately.

Trochlear joint

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

The simplest trochlear joints in the body are the interphalangeal joints, located between the phalanges of the fingers and toes.

Because they bear little body weight and mechanical force, they are composed of simple synovial material with tiny additional ligaments for reinforcement. Each bone is covered with a thin layer of smooth hyaline cartilage, designed to reduce friction at the joints. The bones are also surrounded by a capsule of tough fibrous connective tissue covered by a synovial membrane.

The structure of a person's joint is always different. For example, the elbow joint is more complex, formed between the humerus, radius and ulna bones of the forearm. The elbow is subject to greater stress than the joints of the fingers and toes and therefore contains several strong accessory ligaments and unique bone structures that strengthen its structure.

The ulnar and radial accessory ligaments help support the ulna and radius bones and strengthen the joints. The human legs also consist of several large block-like joints.

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

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

The elbow joint and ankle joint, which have similar anatomy, are most often susceptible to osteoarthritis.

Ellipsoidal joint

The ellipsoid joint, also known as the planus 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, ellipsoidal joints are flexible, while their movement is limited (to prevent injury). Elliptical joints are covered by a synoval membrane, which produces fluid that lubricates the joint.

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

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

Condylar joints

There is a separate type of ellipsoidal joint - the condylar joint. It can be considered a transitional form from a block-shaped joint to an ellipsoidal one. The condylar joint differs from the trochlear joint by 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 ellipsoidal 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 formed like a saddle and the other bone rests on it, like a rider on a horse.

Saddle joints are more flexible than ball and saddle joints.

The best example of a saddle joint in the body is the carpometacarpal joint of the thumb, which is formed between the trapezius bone and the first metacarpal bone. In this example, the trapezium forms a rounded saddle on which the first metacarpal bone 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 firmly grasp objects and use many tools.

Ball and socket joint

Ball and socket 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 joint and shoulder joint are the only ball-and-socket joints in the human body.

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

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

At the hip joint, the rounded, almost spherical head of the femur (femur) fits snugly into the acetabulum, a deep depression in the pelvic bone. A fairly large number of tough 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 dislocation by limiting the movement of the bone within it.

Based on all of the above, you can create a small table. We will not include the structure of the human joint. So, the first column of the table indicates the type of joint, the second and third - examples and their location, respectively.

Human joints: table

Joint type	Examples of joints	Where are they located?
Block-shaped	Knee, elbow, ankle joint. The anatomy of some of them is shown below.	Knee - between the femur, tibia and patella; ulna - between the humerus, ulna and radius; ankle - between the lower leg and foot.
Ellipsoidal	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 joint.	Between the femur and pelvic bone; between the humerus and scapula.
Saddle	Carpometacarpal.	Between the trapezium bone and the first metacarpal bone.

To make it clearer what 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 trochlea and condyle), the radial and trochlear 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 glenohumeral joint is located between the trochlear notch of the ulna and the trochlea (articular surface) of the humerus. This joint is a trochlear joint and is uniaxial.

The humeroradial joint is formed between the condyle of the humerus and the head of the humerus. Movements in the joint occur 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 single-axis.

There is no lateral movement in the elbow joint. In general, it is considered a trochlear joint with a helical sliding pattern.

The largest joints in the upper body are the elbow joints. Human legs also consist of joints that 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 its entire length, except for the fossa. The acetabulum is also covered with cartilage, but only near the semilunar surface; the rest of it is covered with a synoval membrane.

The hip joint includes the following ligaments: the ischiofemoral, iliofemoral, pubofemoral, orbicularis, and the ligament of the femoral head.

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

The next ligament, the ischiofemoral ligament, 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 pubofemoral ligament begins, which goes down to the capsule of the hip joint.

Inside the joint itself is a ligament of the head of the femur. It begins 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 ilium and surrounds the neck of the femur.

The hip and shoulder joints are the only ball-and-socket 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 knee joint capsule 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.

The ligaments of this joint can be divided into two groups: extracapsular and intracapsular. There are also two lateral ligaments in the joint - the tibial and fibular 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 to the edge of the articular cartilage almost along its entire length and departs from it only on the anterior surface of the talus. On the lateral surfaces of the joint there are its ligaments.

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

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

- anterior tibiotalus, 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;

- tibial-scaphoid part, originates from the medial malleolus and ends at the dorsum of the scaphoid bone.

The next ligament, the calcaneofibular ligament, 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 a helical motion.

So, now we have an exact idea of what human joints are. Joint anatomy is more complex than it seems, as 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 articular cavity of the scapula.

Hip joint

This joint experiences a lot of stress, so it is not surprising that its lesions occupy first place in the general pathology of the articular apparatus.

Knee-joint

7 Early Signs of Arthritis

8 Ways to Destroy Your Knees

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General subtleties

In general, the joint is formed by two articulations: the first, the main one, is the femorotibial articulation, the second is formed by the femur and the 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 sagittal, in which flexion and extension occur, which is carried out in the range from 140 to 145 degrees.

Abduction and adduction occur in the frontal plane; it is insignificant, amounting to only 5 degrees. In the horizontal plane, rotation occurs internally, externally, and slight 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, occurring in front, back, and vice versa.

Biomechanics

Joint anatomy is impossible without understanding biomechanics; treatment is based on this. It is complex, its essence lies in 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 movements increases significantly. Stabilization occurs due to the presence of many ligaments, complemented by nearby muscles.
There are menisci inside the cavity; strengthening occurs due to the capsular-ligamentous apparatus, which is covered on top by the muscle-tendon complex.

Soft tissue structures

This is a complex of soft tissues that, 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, it is a lining located between the smooth surfaces of the femoral condyles and tibia. Their anatomy is such that they help eliminate incongruity. In addition, their structure involves depreciation, redistributing the load over the entire surface of the bones. Due to all of the above, the human knee is stabilized, the synovial fluid moves evenly throughout the joint.

Along their periphery, the menisci are tightly connected to the capsule using ligaments. They are distinguished by their strength, because the periphery bears the maximum load.
During movement, the meniscus moves along the surface of the plateau of the tibia; when there is a rupture, this process does not occur, so treatment is required. The menisci are strengthened with the help of collateral cruciate ligaments.

The free edge of the menisci faces the center; a child’s joint, unlike an adult’s, contains blood vessels. The menisci of an adult have them only along the periphery, which is no more than 1/4. Everything is surrounded by a capsule, which has folds and bags, in which liquid is produced. It is nutrition and lubricant for cartilage, the total amount does not exceed a teaspoon. The folds replace the cavities of the knee and create additional shock absorption.

Ligamentous apparatus

In the cavity of the knee joint there are formations - cruciate, paired ligaments. They are separated from the cavity using 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 outwardly located femoral condyle. 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, each individual bundle of ligaments experiences stress. Thus, not only the muscles are involved in strengthening the joint, preventing bone dislocation. Normally, the anterior cruciate ligament, by its tension, prevents even minimal subluxation of the lateral condyle, the plateau of the tibia, when the joint is in its most vulnerable position.

The thickness of the posterior cruciate ligament is 15 mm, its length is up to 30 mm. It originates in the anterior part of the internal femoral condyle, moving downward, outward, and is attached to the posterior surface of the intercondylar eminence behind the tuberosity. The structure of the posterior ligament involves the weaving of some fibers into the joint capsule.

The posterior cruciate ligament prevents the tibia from moving posteriorly and from hyperextension. When a ligament ruptures in a person, this kind of movement becomes possible, and treatment is determined based on the degree of the rupture. The ligament also includes two bundles of fibers.

Extra-articular ligaments

On the inside, the knee is strengthened not only by the muscles, but also by the internal collateral ligament. It contains two portions - superficial and deep. The first portion plays the role of a joint stabilizer; it consists of long fibers that fan out from the inner femoral condyle and 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. If the ligament is completely torn, treatment is reduced to surgery.

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

Muscles

Dynamically, in addition to ligaments, muscles are involved in stabilizing the joint. They surround the joint on both sides, complicating its structure. In case of partial rupture, the muscles of the knee in a person help to further stabilize it. All muscles have their own 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 and strength decreases. During the rehabilitation period, treatment is aimed at restoring its function, which is the most important.

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

Normal and pathological knee

Understanding the processes occurring in the joint optimizes treatment, making it more effective. It is not enough to know the structure of a human joint; what matters is how it functions. The adult and children's joints have articular surfaces that are covered with highly differentiated hyaline cartilage. It consists of chondrocytes, collagen fibers, ground substance, and germ layer.
The load that falls on the cartilage is evenly distributed between all components. A structure based on this principle allows it to withstand pressure or shear loads.

An injury can have a significant impact on the structure of the knee, the mechanism of which largely determines the treatment. Cartilage can be damaged as a result of excessive impact during sudden braking during rotation. When the ligaments are damaged, instability of the joint occurs and it begins to move to the sides. An additional factor complicating treatment may be hemarthrosis, in which blood accumulates in the cavity of the knee joint. The dead cells lead to the release of large amounts of lysosomal enzymes, which ultimately leads to the destruction of joint structures.

Basically, the cartilage in the joint is damaged as a result of external causes. The degree of damage depends on the strength and duration of the damaging factor. Cracks appear, which are the gateway to further destruction of collagen fibers. Vessels sprout from any part of the bone, leading to a decrease in regenerative ability. The bone is also subject to destruction processes.

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

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Anatomy and movement of joints

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 desired bone in motion. Depending on the freedom of movement of the joint axis, the action is performed in one direction or another. The cartilage of the articular surfaces increases the diversity of movement functions.

A significant role is played by muscle groups that contribute to the movement of joints. The structure of the ligaments consists 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 joint 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 shape of joints in medicine are usually divided into classes in a simple way. Classification of joints:

Uniaxial. Block type (finger phalanges), cylindrical joint (radio-ulnar joint).
Biaxial. Saddle joint (carpometacarpal), elliptical type (radiocarpal).
Multi-axis. Ball-and-socket 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. An articulation refers to a type of joint where the ends of the bone surfaces sit on top of each other. The volume of movement occurs along the axis along its ends. Such joints are often found at the base of the upper and lower limbs.
Ball-shaped type. The structure of the joint is represented by a convex shape of the head on one bone and a depression on the other. This joint is a multi-axis joint. The movements in them are the most mobile of all, and are also the freest. It is represented in the human torso by the hip and shoulder joints.
Complex joint: In humans, this is a very complex joint, forming a body complex of two or more simple joints. Between them, an articular layer (meniscus or disc) is placed on ligaments. They hold the bone one next to the other, preventing lateral movements. Types of joints: kneecap.
Combined joint. This connection consists of a combination of several joints that are different in shape and are isolated from one another, performing joint functions.
Amphiarthrotic, or tight joint. It contains a group of strong joints. The articular surfaces sharply limit movement in the joints for greater density, there is practically no movement. They are present in the human body where movements are not needed, but strength 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 located joint surfaces in the articular capsule. Axes of rotation are possible around all planes, which is explained by the slight 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 ellipsoidal types of joint structure.
Block type. The articulation here is a cylindrical process located against the underlying cavity on the bone and is surrounded by an articular capsule. It has a better connection, but less axial mobility than the spherical type of connection.

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

Connection of cranial bones

The human skull has 8 paired and 7 unpaired bones. They are connected to each other by dense fibrous sutures, except for the bones of the lower jaws. The development of the skull occurs as the body grows. In newborns, the bones of the skull roof are represented by cartilaginous tissue, and the sutures still bear little resemblance to a joint. With age, they become stronger, gradually turning into hard bone tissue.

The bones of the facial part fit smoothly to each other and are connected by even sutures. In contrast, the bones of the medulla are connected by scaly or serrated sutures. The mandible is attached to the base of the skull by a complex ellipse-shaped complex biaxial joint. Which allows jaw movements along all three types of axes. This is due to the daily process of eating.

Spinal joints

The spine consists of vertebrae, which form articulations with each other with their bodies. The atlas (first vertebra) is attached to the base of the skull using condyles. It is similar in structure to the second vertebra, which is called 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 the 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. Intervertebral hernias most often occur in this department, due to improper loads and poor muscle development in this area.

Next comes 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 spine in the sacral region is fully formed by the age of 28. At this time, the separate vertebrae fuse into one section.

The structure of the joints of the lower extremity belt

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

The legs have many ligaments and joints, of which the ball-shaped hip joint is the most mobile. It is this that, in childhood, little gymnasts and gymnasts begin to confidently develop. The largest ligament here is the femoral head. In childhood, it stretches unusually, which determines the early age of gymnasts’ competitions. At the early level of pelvic formation, the ilium, pubis and ischium are formed. They are initially connected by the joints of the lower extremity belt into a bone ring. Only by the age of 16–18 do they ossify and fuse into a single pelvic bone.
In medicine, the most complex and heaviest structure is the knee. It consists of three bones, which are located in a deep interweaving of joints and ligaments. The knee joint capsule itself forms a series of synovial bursae, 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 extended position, it already works as a block-shaped type. When the ankle bends, rotational movements occur in it. The knee joint claims to be the most complex joint. At the same time, you need to carefully take care of it, and not overdo it with overloads on your legs, because restoring it is very, very difficult, and at a certain stage it is even impossible.
Regarding the ankle joint, it is necessary to keep in mind that the ligaments lie on its lateral surfaces. It connects a large number of large and small bones. The ankle joint is a block-type joint in which screw motion 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 connections 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 is subject to everyday stress in human life, and also has an important shock-absorbing effect. It consists of many small joints.

The structure of the joints of the upper limb belt

The hand includes many joints and ligaments that are capable of very finely regulating the actions and motor skills of the smallest movements. One of the most complex joints here is the shoulder. It has many fastenings and interweavings of ligaments, which are difficult to adjust one to one. The main three large ligaments are responsible for abduction, adduction, raising the arms to the sides, anteriorly and upward.

Raising the arm above the shoulder introduces movement to the muscles and ligaments of the scapula. The shoulder is connected to the scapula by a powerful fibrous ligament, which allows a person to perform various complex and difficult activities with heavy weights.

The classification of the elbow joint is very similar in structure to the structure of the knee joint. It 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, there is a blocking of complete movement. Due to the fact that the elbow joint involves the humerus and ulna bones in movement, 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. The underlying nerves and blood vessels pass through it to the end of the arm.

The muscles of the wrist and metacarpus begin to attach near the wrist joint. Many thin ligaments regulate motor movement both on the back of the hand and on the sides.

Humans inherited the thumb joint from monkeys. Human anatomy is similar to the structure of our ancient relatives precisely in this joint. Anatomically, it is determined by grasping reflexes. This bone articulation helps interact with many objects in the environment.

Joint diseases

In humans, joints are perhaps the most susceptible to disease. Among the main pathologies, it is necessary to highlight hypermobility. This is a process where there is increased activity of bone joints that goes beyond the permissible axes. Undesirable stretching of the ligaments occurs, allowing the joint to make deep movement, which has an extremely bad effect on 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, how this remains to be determined by doctors and scientists.

Hypermobility is often detected in young girls and is genetically determined. It leads to deformation of connective tissues and especially bone joints.

With this type of illness, it is highly not recommended 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 more hyperextension of the ligaments. Which, in turn, ends with varicose veins or arthrosis.

The most common localization of diseases:

Shoulder girdle diseases often occur in people in old age, especially in those who are accustomed to making a living through hard physical labor. People who go to the gym very often are also in the critical zone. Subsequently, old age is accompanied by pain in the shoulders (shoulder arthritis) and osteochondrosis of the cervical spine. Doctors often find osteoarthritis or arthritis of the shoulder joint in people in this category.
Elbow diseases also often plague athletes (epicondylitis). As people age, their joints experience discomfort and limited mobility. They are caused by deforming osteoarthritis, arthritis and inflammation of the arm muscles. Therefore, it is necessary to remember the correct technique and time of practice.
The joints of the arms, fingers and hands become inflamed in rheumatoid arthritis. The disease manifests itself as “tight glove” syndrome. Its peculiarity is that both hands are affected. 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 for a long time every day.
In the hip area, coxarthrosis is most often identified. A typical disease in older people is osteoporosis (softening of the femur structure). Bursitis and tendinitis of the hip joint occur in runners and football players.
Diseases in the knee are detected in people of all age groups, since it is a very complex complex. Its restoration in 90% of cases is impossible without surgical intervention, which, in turn, does not guarantee complete cure of this connection.
The ankle is characterized by arthrosis and subluxation. Pathologies are classified as professional in dancers and women who often use high heels. Osteoarthritis affects people who are obese.

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

It would be difficult to imagine a person’s life without precise and confident movements. Regarding any profession where a person’s physical skills are 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 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 support organ and began to perform this function both in the body itself and in environmental conditions (on land, in water, in the air). However, not all bones or cartilage are connected to each other using joints. In some cases, in the absence of diastasis, two bones are connected to each other by dense connective tissue, similar to an interosseous membrane. In other cases, a continuous cartilaginous connection is formed between adjacent bones. Sometimes initially independent bones grow together into a single bone mass. Consequently, some special conditions are necessary for the formation of joints.

To determine what these conditions are, let's first analyze the simpler forms of bone connection. Thus, in conditions when a bone is constantly displaced 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, a moment comes 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 move relative to each other over a wide range, and also move away from each other at the moment of displacement. In the second case, not only does the range of displacement decrease, but also the bones move closer together, which inevitably leads to increased pressure from 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 on another. It is under these conditions that joints with all their characteristic elements are formed. That this is exactly the case is evidenced by different types of joints and those components that are essential attributes of each joint.

To successfully control the function, it is necessary to know, at least in general terms, the biomechanics and structural features of joints (A general analysis of large joints is given as the most obvious example).

Shoulder joint (articulatio humeri). Formed by the head of the humerus and the glenoid cavity of the scapula. It has a spherical shape and is the most mobile joint in humans; surrounded by a thin and freely sagging bag. The ligamentous apparatus is represented only by the coracobrachial 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 (inward rotation) and supination (outward rotation); 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, they are joined by friendly movements of the entire girdle of the upper limbs (scapula, collarbone) and the spinal column.

The muscles play the main role in maintaining the contact of articulating bones, but they often fail to cope with it. With significant fatigue and reflex relaxation of the muscles, the head can separate from the fossa, and after the load stops, return to its place. This phenomenon is encountered by those who regularly carry quite heavy loads. The coincidence of the articular surfaces is also disrupted when performing movements of extreme range - especially flexion and abduction. This, in particular, explains the increased likelihood of injury to the shoulder joint, which can only be reduced with regular strength training of the muscles surrounding it.

Maximum flexion and abduction in the shoulder joint is limited by the thrust of the humerus into the humeral process of the scapula (acromion). Some further movement in this direction is possible even after the bones come into contact - due to disruption of the contact of the head and the fossa. In some cases, the sagging joint capsule may end up between the bone abutments; its infringement occurs, which is not eliminated 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 bursa.

The amplitude of extension and abduction (especially during active execution) depends on the rotation of the arm inward or outward. Supination increases extension by 15-20°. When the arm pronates, 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 bursa and articular cavity.

The main load when performing most movements is borne by the shoulder-elbow joint. It belongs to the trochlear type and has only one - transverse - axis of rotation around which flexion and extension occur. The humeral joint has a spherical shape, the proximal radioulnar joint has a cylindrical shape. Thanks to these joints and the distal radioulnar joint, pronation and supination of the forearm are carried out around the longitudinal axis of the joint. 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, minor 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 trochlear humerus reaches 320°, and the trochlear notch of the ulna reaches 180°. This ratio allows for movement with a range of about 140°.

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

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

In the vast majority of people, flexion and extension are performed in full and do not require additional training to increase mobility. Natural pronation-supination in everyday life is also quite enough. Special needs may arise when playing certain sports: basketball, table tennis, artistic 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, slight abduction and adduction can be performed passively, under the influence of an external force. This occurs, for example, in all throwing movements of a “whip-like”, ballistic nature. It should be emphasized that these movements are “not provided for” by the structure of the elbow joints. During their execution, the radial and ulnar collateral ligaments are overstrained and, if the load is high enough, injured.

Thus, when training the elbow joint, the only goal is usually to strengthen it. There is no need to develop mobility - it is enough to maintain it at the level necessary to perform the assigned motor tasks. On the contrary, there may be a need to limit excessive mobility - for example, congenital hyperextension in the elbow joint. This fairly common phenomenon - mainly of hereditary origin - is 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 creates the impression of unnaturalness, fragility, and vulnerability.

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

Wrist joint (articulatio radiocarpea). Formed by the articular surface of the radius and the ellipsoidal surface of the bones of the proximal row of the wrist (scaphoid, lunate and triquetrum). The ulna, equipped at the lower end with a cartilaginous fibrous disc, also takes part in the formation of the joint, contributing (especially when resting on the hand) to distribute pressure over a large area.

The wrist joint performs flexion, extension, adduction and abduction of the hand. Its pronation and supination occur together with the rotation of the distal ends of the forearm bones. Slight true rotation of the hand is possible only under the influence of 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 small mobility in the midcarpal and intercarpal joints, forming a complex kinematic chain.

The ligamentous apparatus of the wrist joint is very complex. Going in a variety of directions, the ligaments densely entwine 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 carpal bones and the styloid processes present at the ends of the ulna and radius. Impact of these motion restrictors is one of the most common causes of injury to the wrist joint. The two main ligaments of the joint are attached to these processes - the lateral ulnar and lateral radial.

Hip joint (articulatio coxae). Formed by the acetabulum of the pelvic bone and the head of the femur. It has a strong thick capsule, reinforced by the iliofemoral, ischiofemoral and pubofemoral ligaments. These ligaments are highly stressed during extension and rotation of the leg from the main stance position and remain passive during flexion. The ligament of the femoral head, located inside the joint capsule, is stretched only with extreme adduction of the hip. In all other cases, it, like a pillow, absorbs impacts 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 occur. It has less mobility than the shoulder joint. This is explained by greater congruence (coincidence) of the articular surfaces, a more powerful ligamentous apparatus and the surrounding massive muscles. It is almost impossible to fix isolated movements of the thigh in the hip joint without special devices, since they are always accompanied by concomitant 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 in muscles and ligaments is already observed in a normal standing position. As a result, the hip is gradually fixed in a certain familiar average position, and its mobility is limited. Thus, special gymnastics for the joint, aimed primarily at preserving the natural range of motion and appropriate training of all its elements, becomes necessary.

Rational training over several months can increase the amplitude of maximum hip flexion by 30-40° or more.

Extension at the hip joint is inhibited by the tension of the powerful iliofemoral ligament. Actually, it is already tense in the position of the main post 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 a sharp or swinging one) must be performed carefully. Increasing hip mobility in this direction requires many years of systematic training. It should be remembered that a supinated (externally rotated) hip can be abducted much further than a non-supinated one, since in this case the greater trochanter leaves the plane of movement and no longer limits it.

The amount of pronation and especially supination quickly decreases with age. Systematic exercises make it possible not only to maintain, 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 the trochlear and spherical joints. From the extended position, only flexion is possible. As you flex, due to a decrease in the radius of curvature of the femoral condyles, the fibular and tibial collateral ligaments relax. The joint receives another degree of freedom; Limited pronation and supination of the lower leg become possible. The axis of these movements runs vertically - approximately in the center of the medial femoral condyle.

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

The congruence of the articular surfaces is increased by fibrocartilaginous concave spacers - menisci. They also help soften shocks and shocks and distribute the pressure of the condyles over 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 leverage of the quadriceps muscle.

The vast majority of people experience complete flexion of the tibia, up to the point of contact with 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 for these movements - other than training to strengthen the joint.

The hyperextension that occurs is blocked by increasing the strength of the lateral ligaments and the bursa (especially in its posterior part), as well as the elasticity of the muscles of the lower leg and thigh, which spread over the joint. Using a specially simulated load, it is possible to increase the strength of the attachment of the menisci to the articular surface of the tibia, which can be damaged under strong impact loads directed from top to bottom and torn from their attachment points as a result of hyperextension and excessive rotation.

It is also necessary and possible to strengthen the cruciate ligaments, which prevent the femur from sliding forward and backward and are greatly strained when the tibia rotates. Strengthening is carried out using moderate, controlled and regular loads.

With strong bending under load, a “dead position” occurs, as weightlifters say, when the powerful forces of the thigh muscles are only to a small extent involved in extending the leg. Most of them are spent on deformation of the knee joint: its cup is pressed between the condyles of the femur; all elements of the joint are overstrained - cartilage, ligaments, menisci, numerous synovial bursae. The attachment of the quadriceps tendon 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 sizes of the external and internal condyles of the femur. When creating a training regimen, this circumstance must be taken into account. Significant deviations from the norm can become an obstacle to successful participation in 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 internal epicondyles of the femurs, 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 knee joint index is calculated. Deviations with an index of up to 3.0 should be considered insignificant; from 3.5 to 5.0 - noticeable; over 5.0 - large.

Ankle joint (articulatio talocruralis). Formed by the bones of the tibia and the talus. It has a block-like shape and one, transverse, axis of rotation. Because the trochlea of the talus is somewhat narrower posteriorly than anteriorly, as the joint flexes, it exhibits limited ability for passive lateral and rotational movements. However, these movements are quite difficult to isolate, since they are masked by the mobility of the distal tarsal joints (subtalar, talocalcaneal-navicular, etc.), with which the ankle joint forms a kinematic chain.

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

Extreme flexion and extension of the foot at the ankle joint limits the emphasis of the edges of the tibia on the neck or on the posterior process of the talus. Long-term exercise can slightly change the configuration of these movement limiters and significantly increase the mobility of the foot. Aging of an underused ankle joint begins precisely at the anterior and posterior edges of the talus trochlea.

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 amount of angular displacement of two adjacent vertebrae during tilting and bending depends mainly on the height and elasticity of the discs. The thickest discs are located in the lumbar spine, the thinnest are in the middle part of the thoracic spine, where the relative mobility of adjacent vertebrae is extremely low. In the cervical region, the discs are quite thin, but the height of the vertebral bodies is much smaller. Therefore, the flexibility of the cervical spine is approximately the same as that of the lumbar spine.

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 torso.

Individual fluctuations in the flexibility of various parts of the spine are very large. It has been noted that in people with little flexibility, the degree of angular displacement of the vertebral bodies is regulated primarily by ligaments running along the spine. With good flexibility, the muscles of the torso come to the fore, which are naturally more extensible. The less flexibility of the thoracic region when performing any movements is explained primarily by the fact that ribs are attached to its vertebrae, limiting the possibility of angular displacement of the vertebrae.

The cervical spine retains some autonomy during body movements and does not necessarily participate in these movements. It also implements flexion-extension, tilting left and right, and rotation. This department requires special exercises and regular joint work.

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

No matter how small the mobility of these joints is, its significance is very great: thanks to it, with great effect and with less energy expenditure, the volume of the chest changes during inhalation and exhalation. There is evidence that a large vital capacity of the lungs is always combined with greater mobility of the ribs, which can be trained. In addition to special exercises, rowing, swimming, and skiing have a beneficial effect on the mobility of the ribs. It should be noted that spinal flexibility training is also an effective means of increasing rib mobility.

Shoulder girdle joints. Connect the sternum to the collarbone and the collarbone to the scapula. They have both their own mobility and dependent mobility, which is mobilized during all kinds of hand movements and increases their maximum amplitude. This is especially important when the intrinsic 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 amount of 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 a wide range of motion (shoulder, knee, etc.). These and similar joints are characterized by a large range of movements: their articular surfaces are little congruent, and the difference in the areas of the articular surfaces is very significant; the joint capsule and ligamentous apparatus slightly impede movement. We can say 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: articulations of the vertebral bodies - articulatio intervertebralis, sacroiliac joint - articulatio sacroiliaca; tight joints. intercarpal joints - articulatio mediocarpea, articulations between the tarsal bones - 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 a moderate range of motion , occupying an intermediate place between the two previously indicated groups (ankle - articulatio talocruralis, wrist - articulatio radiocarpea, etc.). In these joints, all their components are moderately developed.

The classification of joints by range of motion attracts attention because it emphasizes the role of function in the formation of a joint. If part of the embryo’s limb 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 the 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 joints are formed ends of bones, capsule, etc. The absence of movements in the joint (and it is known that fetal movement begins in the first months of intrauterine life) leads to the fact that the initially formed joint cavity becomes overgrown, and the articular ends of the bones grow together.

If an adult does not use a limb for a long time and there is no movement in the joint, then after some time the volume of these movements is sharply reduced; subsequently, so-called ankylosis occurs - a complete lack of movement in this joint. Conversely, with systematic exercises to develop mobility in the joint, you can achieve a significant increase in the range of motion.

Two important circumstances 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 and the severity of its 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, by the state of the joint elements one can judge the influence 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 control 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 connection through fibrous connective tissue. In this way, for example, parts of the exoskeleton in invertebrates are connected. A more complex form of connection between parts of the skeleton is connection through cartilage tissue, for example, in the skeleton of fish. The most developed form of bone connection 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, humans have preserved all 3 types of connections.

DEVELOPMENT OF BONE JOINTS

Bone joints develop in close relationship with the development of the bones themselves. In humans, continuous connections are first formed as simpler ones - in the 6th week of the intrauterine period. In the embryo, in the cartilaginous anlages of the bones, where connections should be formed, a concentration of mesenchyme and a 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 in the 8-9th week, a rarefaction of mesenchyme occurs 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 and 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 layer, consisting of fibrous

connective tissue, and internal epithelial - synovial membrane. The joint ligaments are formed from the mesenchyme adjacent to the joint, which forms the capsule.

In the second half of the embryonic period, intra-articular 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 the 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 the intra-articular cavity is completed at different times.

GENERAL ARTHROLOGY

Bones can connect to one another using a continuous connection when there is no gap between them. This connection is called synarthrosis(synarthrosis). A discontinuous connection in which a cavity is located between the articulating bones and forms joint(articulatio), called diarthrosis, or synovial junction(juncturae synovialis).

Continuous connections of bones - synarthrosis

Continuous bone connections (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 - synostoses (synostoses).

To fibrous joints include syndesmosis, interosseous membrane and suture.

Syndesmosis(syndesmosis)- This is a fibrous connection through ligaments.

Ligaments(ligamenta) serve to strengthen bone joints. They can be very short, for example 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 cords consisting of longitudinal, oblique and overlapping bundles of collagen and a small amount of elastic fibers. They can withstand high tensile loads. A special type of ligament is the yellow ligament (ligg.flava), formed by elastic fibers. They are durable and

Rice. 32. Continuous connections:

a - syndesmosis; b - synchondrosis; c - symphysis; d, e, f - impacting (dental-alveolar junction); g - serrated seam; h - scaly suture; and - flat (harmonious) seam; k - interosseous membrane; l - ligaments

strength of fibrous syndesmoses, at the same time they are characterized by great extensibility and flexibility. These ligaments are located between the vertebral arches.

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

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

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

Serrated (sut. serrata)- the edge of one bone has teeth that fit into the depressions between the teeth of another bone: for example, when connecting the frontal bone with the parietal bone;

Scaly (sut. squamosa) formed by placing obliquely cut bones on top of each other: for example, when connecting the scales of the temporal bone with the parietal bone;

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

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

In cartilaginous joints(juncturae cartilaginea) The 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 slight 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 that connect 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 the neighboring bones - the sphenoid and occipital.

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

If a temporary continuous connection (fibrous or cartilage) is replaced by bone tissue, 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 the halves of the lower jaw.

Discontinuous bone connections - diarthrosis

Discontinuous bone connections - 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: articular surfaces, covered with articular cartilage; joint capsule, covering the articular ends of the bones and strengthened by ligaments; joint 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). Typically, one of the articulating articular surfaces is convex, the other concave. The structure of cartilage can be hyaline or, less commonly, fibrous. The free surface of the cartilage, facing the joint cavity, is smooth, which facilitates movement

Rice. 33. Joint structure diagram:

1 - synovial membrane; synovial layer; 2 - fibrous membrane; fibrous layer; 3 - fat cells; 4 - articular 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 smoothes 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: the outer layer - a 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 with 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 adiposae). If the synovial membrane bulges outward, synovial bursae (bb. synoviales). They are located in areas of greatest friction, under 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 found in the articular capsule of the knee joint.

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

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

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

Articular disc (discus articularis) and articular meniscus (meniscus articularis) They 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 we speak of a disc. If the division of the joint cavity is incomplete, then they speak of menisci: for example, menisci in the knee joint. Articular cartilage promotes congruence of articulating surfaces and reduces the impact of shocks.

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

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

Sesamoid bones (ossa sesamoidea) located in the joint capsule 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 divided depending on the shape and number of articulating surfaces or functions (the number of axes around which movements are made in the joint). The following forms of joint movements are distinguished:

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

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

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

The range of motion in the joints is determined by 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 articular surfaces almost equal in area, 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 conventionally compared with geometric bodies (sphere, ellipse, cylinder). They are classified by shape and distinguish between spherical, flat, ellipsoidal, saddle-shaped, trochlear and other joints. Based on the number of axes, multiaxial, biaxial, and uniaxial joints are distinguished. The shape of the articular surfaces also determines the functional mobility of the joints and, therefore,

number of axes. Based on the shape and number of axes, we can distinguish: uniaxial joints - block-shaped, cylindrical; biaxial joints - ellipsoidal, condylar, saddle-shaped; 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 is shaped like a cylinder, and the articular surface of the other bone is shaped like a cavity. In the radioulnar joint, movements occur 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 block-shaped(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 ridge in the middle. The groove and ridge prevent lateral slip. An example of a trochlear joint is the interphalangeal joints of the fingers, which provide flexion and extension. Type of trochlear joint - helical joint(articulatio cochlearis), in which the groove on the articulated surface is located somewhat obliquely with respect to the plane perpendicular to the axis of rotation. As this groove continues, a screw is formed. These joints are the ankle and the humeral-ulnar.

Biaxial joints.Elliptical joint(articulatio ellipsoidea) the shape of the articular surfaces approaches an ellipse. In this joint, movements around two axes are possible: frontal - flexion and extension, and sagittal - abduction and adduction. In biaxial joints, circular rotation is possible. Examples of biaxial joints are the wrist and atlanto-occipital. Biaxial also includes 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 elliptical joint. An example of such a joint is the carpometacarpal joint of the thumb. Condylar joint(articulatio bicondylaris) refers to biaxial (the shape of the articular surfaces is close to elliptical). In such a joint, movements around two axes are possible. An example is the knee joint.

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

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

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

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

Rice. 34.2.Patterns of joint movements:

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 - trochlear 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 - outward and inward rotation. An example is the shoulder joint. If the glenoid 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 cup-shaped(articulatio cotylica). Multiaxial joints include flat joint(articulatio plana), the articular surfaces of which are slightly curved and represent 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 a joint, then the joint is called simple(articulatio simplex), if 3 or more - complex(articulatio composita). An example of a simple joint is the shoulder, and a complex joint 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.

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

The joints 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 for people of different ages, genders and fitness levels.

Blood supply and innervation of joints

The joints are supplied with blood by the branches of the main arterial trunks, which pass nearby. Sometimes a vascular network of several arteries is formed on the surface of the joint, for example the arterial networks of the elbow and knee joints. The outflow of venous blood occurs into the venous vessels that accompany the arteries of the same name. The joints are innervated by nearby nerves. They send nerve branches into the articular capsule, forming a number of branches and terminal nerve apparatus (receptors) in it. Lymph drainage occurs to nearby regional lymph nodes.

CONNECTION OF BONES OF THE TORSO

Spinal column connection

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. On the outside it is formed by a fibrous ring (anulus fibrosus), the fibers of which run in an oblique direction to adjacent vertebrae. The nucleus pulposus is located in the center of the disc (nucl. pulposus), which is a remnant 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 greatest in the lumbar region, the smallest in the thoracic region.

There are 2 longitudinal ligaments running along 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 arch of the atlas and stretches to the first sacral vertebra. This ligament prevents excessive extension of the spine. Posterior longitudinal ligament(lig. longitudinale posterius) runs inside the spinal canal from the body of the second cervical vertebra to the first sacral vertebra. It prevents excessive flexion of the spine.

The connections between the arches and processes are referred to as syndesmoses. So, between the arches of the vertebrae there are strong yellow ligaments(ligg.flava), between the spinous processes of the vertebrae - interspinous ligaments(ligg. interspinalia), which at the tips of the processes turn into supraspinous ligaments(ligg. supraspinalia), running in the form of a round longitudinal cord along the entire length of the spinal column. In the cervical region, the ligaments above the VII vertebra thicken in the sagittal plane, extend 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 located intertransverse ligaments(ligg. intertransversaria).

Rice. 35. Connections of the spinal column: a - side view (the left half of the vertebrae has been partially removed): 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 (vertebral arches removed): 1 - posterior longitudinal ligament; 2 - intervertebral disc; c - view from the side of the spinal canal at the vertebral arches: 1 - vertebral arch; 2 - yellow ligament

Facet joints

The lower articular processes of the vertebra articulate with the upper articular processes of the underlying vertebra using facet joints(articulationes zygapophysiales). According to the shape of the articular surfaces, they are considered 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 articulations of the vertebrae with each other.

Sacrococcygeal joint(articulatio sacrococcygeal) has some features due to the loss of the coccyx's characteristic structure for the vertebrae. Between the bodies of the V sacral and I coccygeal vertebrae there is an intervertebral disc, as in true vertebral joints, but inside it, instead of the nucleus pulposus, there is a small cavity. Runs along the anterior surface of the coccyx ventral sacrococcygeal ligament(lig. sacrococcygeum ventrale), which is a continuation of the anterior longitudinal ligament. Along the posterior surface of the bodies of the sacral vertebrae and coccyx there is deep dorsal sacrococcygeal ligament(lig. sacrococcygeum dorsale profundum)- continuation posterior longitudinal ligament(lig. longitudinals posterius). The inferior sacral foramen is closed superficial posterior sacrococcygeal ligament(lig. sacrococcygeum posterius superficialis), running from the dorsal surface of the sacrum down to the posterior surface of the coccyx. It corresponds to the supraspinous and yellow ligaments. Lateral sacrococcygeal ligament(lig. sacrococcygeum laterale) runs along the lateral surface of the sacrum and coccyx.

CONNECTION OF THE I AND II CERVICAL VERTEBRES BETWEEN THEM AND WITH THE SKULL

The connections of the condyle in the occipital bone with the superior articular fossae of the atlas form a combined ellipsoid atlanto-occipital joint(articulatio atlantooccipitalis). Movements around the sagittal axis are possible in the joint - 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 strengthened by strong ligaments. Between the anterior and posterior arches of the atlas and the edge of the foramen magnum are stretched anterior and posterior atlanto-occipital membranes(membranae atlantooccipitales anterior et posterior)(Fig. 36). Atlas spreads between the lateral masses transverse ligament of the atlas(lig. trasversum atlantis). From the upper free edge of the transverse ligament passes the 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 atlanto-occipital membrane; 5 - anterior atlanto-occipital membrane; 6 - anterior longitudinal ligament;

b - upper part of the spinal canal, rear view. Vertebral arches removed

and spinous processes: 1 - lateral atlantoaxial joint; 2 - atlanto-occipital joint; 3 - occipital bone; 4 - cover membrane; 5 - posterior longitudinal ligament; c - in comparison with the previous figure, the integumentary membrane has been 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 was removed:

1- ligament of the apex of the tooth; 2 - pterygoid ligament; 3 - atlanto-occipital joint; 4 - lateral atlantoaxial joint;

e - median atlantoaxial joint, top view: 1 - transverse atlas ligament;

2-pterygoid ligament

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

SPINAL COLUMN AS A WHOLE

Spinal column(columna vertebralis) consists of 24 true vertebrae, sacrum, coccyx, intervertebral discs, articular and ligamentous apparatus. The functional importance of the spine is enormous. It is the receptacle 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 foramina between the vertebrae above and below (forr. intervertebralia), where the spinal nodes lie, blood vessels and nerves pass through. The intervertebral foramina are formed by the inferior notch of the overlying vertebra and the superior notch of the underlying vertebra.

The human spine has curves in the sagittal plane (see Fig. 18.1). In the cervical and lumbar regions, the spine forms curves with the convexity directed anteriorly - lordosis(lordosis), and in the thoracic and sacral regions - bends directed posteriorly - kyphosis(kyphosis). The bends of the spinal column give it spring properties. Curves are formed in the postnatal period. At the 3rd month of life, the child begins to raise his head, and cervical lordosis appears. When the child begins to sit, thoracic kyphosis develops (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- represent pathological curvatures. In old age, the spine loses its physiological curves; as a result of 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 spaces corresponding to the intervertebral discs, vertebral arches, spinous and articular processes, joint spaces, and intervertebral foramina are visible. The shadows of the transverse processes are superimposed on the shadows of the vertebral bodies. X-rays of the spinal column make it possible to study its bends and structural features of each section.

Radiographs in direct projections also show details of the structure of the vertebrae and intervertebral spaces, and the transverse processes in the cervical and lumbar spine are free from overlap, and in the thoracic spine they are aligned with the posterior ends of the ribs. The spinous processes overlap the vertebral bodies. Radiographs of the sacrum and coccyx show the sacral foramen, lumbosacral and sacroiliac joints.

JOINTS OF THE CHEST

Connection of the ribs to the sternum and spine

The seven true ribs are connected to the sternum by means of the costal cartilages, and the cartilage of the first rib is connected by synchondrosis to the manubrium 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 head joint (articulatio capitis costae), the other is the costotransverse joint (articulatio costotransversaria) between the costal tubercle and the transverse process of the vertebra (Fig. 37).

CHEST IN GENERAL

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 protecting organs located

Rice. 37. Connection of the ribs to the sternum and spine:

a - connection with the sternum: 1 - costal cartilages; 2 - radiate sternocostal ligament; 3 - collarbone; 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 - joint of the rib head, strengthened by the radiate ligament

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

Superior thoracic outlet (apertura thoracis superior) bounded posteriorly by the body of the first thoracic vertebra, laterally by the first rib, and anteriorly by the sternum. Inferior thoracic outlet (apertura thoracis inferior) limited posteriorly by the body of the XII thoracic vertebra, laterally and anteriorly 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 to the sternum (X), forming the substernal angle (angulus infrasternalis), the dimensions of which are determined by the shape of the chest. The spaces between adjacent ribs are called intercostal (spatium intercostale).

The shape of the chest varies and depends on body type, age and gender. There are two extreme forms of the chest: narrow and

long, with low ribs and a sharp substernal angle; wide and short, with a greatly expanded lower aperture and a large substernal angle. A woman's chest is more rounded, steeper and narrower in the lower section. In men, its shape is close to a cone; all its dimensions are larger.

X-ray anatomy of the chest

A chest x-ray in the anteroposterior projection shows the dorsal segments of the ribs, which are directed laterally and downward, and the anterior segments of the ribs, which are directed in the opposite direction. The costal cartilages do not produce shadows. The sternoclavicular joints, sternum, and intercostal spaces are clearly visible.

Questions for self-control

1.List the types of connections. Give their characteristics.

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

3.Name the continuous connections of bones.

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

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

6. How are the 1st and 2nd cervical vertebrae connected to each other and to the skull?

7.What shapes of the chest are found depending on body type, age and gender?

CONNECTION OF LIMB BONES

Joints of the upper limb

Joints of the upper limb belt

AC 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 articular cavity there is articular disc(discus articularis). The joint is strengthened by the following ligaments: coracoclavicular (lig. coracoclaviculare), going 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 acromion.

In the girdle of the upper limb, the coracoacromial ligament is also distinguished (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 upward abduction of the arm.

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, there is an articular disc inside the joint cavity, dividing 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 disc, the joint approaches spherical. Movements 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 first 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 joint disc; interclavicular ligament (lig. interclaviculare), which connects both sternal ends of the clavicle above the jugular notch.

Rice. 38.Sternoclavicular joint, front view. The right joint is opened with a frontal incision:

1 - articular disc; 2 - interclavicular ligament; 3 - anterior sternoclavicular ligament; 4 - collarbone; 5 - costoclavicular ligament; 6 -I rib; 7 - manubrium 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, a labrum is formed along the edge of the glenoid cavity (labrum glenoidale). The articular capsule is thin, free, starts from the edge of the articular labrum and is attached to the anatomical neck of the humerus. The tendon of the long head of the biceps brachii muscle 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 coracobrachial ligament (lig. coracohumerale), starting from the coracoid process of the scapula and intertwining with the joint capsule. The shoulder joint is surrounded by muscles on the outside. Muscle tendons, surrounding

Rice. 39. Shoulder joint, right, front view (capsule and ligaments of the joint): 1 - coracobrachial ligament; 2 - coracoacromial ligament; 3 - coracoid process; 4 - blade; 5 - articular capsule; 6 - humerus; 7 - tendon of the long head of the biceps brachii muscle; 8 - tendon of the subscapularis muscle; 9 - acromion

compressing the joint, not only strengthen it, but also, when moving in the joint, pull back the joint capsule, preventing it from being pinched. According to the shape of the articulated surfaces, the joint belongs 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 brachii; 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-ulnar joint(articulatio humeroulnaris) formed by the trochlea of the humerus and the trochlear notch of the ulna. The joint is trochlear, with a helical deviation from the midline of the trochlea.

Humeral joint(articulatio humeroradial)- this is the articulation of the head of the humerus 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: the frontal one - flexion and extension, and the vertical one, passing through the shoulder-elbow joint - pronation and supination.

The elbow joint contains the following ligaments: 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 by a combined joint. The proximal radioulnar joint is 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 a vertical axis passing through the head of the radius and ulna. A tendinous interosseous membrane is stretched between the interosseous ridges of the radius and ulna. (membrana interossea antebrachii) with openings 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.

Joints of the hand

Wrist joint(articulatio radiocarpea) is complex (Fig. 41). The shape of the articular surfaces is elliptical. His

Rice. 41. Joints and ligaments of the hand: a - front view: 1 - distal radioulnar joint; 2 - ulnar collateral ligament of the wrist; 3 - pisiform-hook ligament; 4 - pisiform-metacarpal ligament; 5 - hook of the hamate; 6 - palmar carpometacarpal 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 - radiate 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, triquetrum). An articular disc separates the distal radioulnar joint from the radiocarpal joint. Movements around the frontal axis - flexion and extension, and around the sagittal axis - abduction and adduction are possible.

Wrist joints, intercarpal joints(articulationes intercarpales) connect the bones of the wrist. These joints are strengthened 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 wrist bones), front view: 1 - radius bone; 2 - wrist joint; 3 - radial collateral ligament of the wrist; 4 - midcarpal 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 extensor carpi ulnaris, and the triquetrum 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 belong to flat joints. They are strengthened by palmar and dorsal ligaments.

Carpometacarpal joint of the thumb(articulatio carpometacarpea pollicis) formed by the trapezium bone and the base of the first 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.

Intermetacarpal 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 fossae of the bases of the proximal

phalanges of fingers. The metacarpophalangeal joints of the II-V fingers have a spherical shape. The joints are strengthened by ligaments. Movements in them are possible around the frontal axis - flexion and extension, the sagittal axis - abduction and adduction; Rotational movements are also possible, and in the first 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 the bases of the distal phalanges. These are block-shaped joints in shape. Ligaments run along the lateral surfaces of the joint. Movements in the joint are possible around the frontal axis - flexion and extension.

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

Differences in the shape of the joints are due to the functional characteristics of the upper limb. Thus, the structure of the joints of the upper limb girdle depends on individual characteristics. In people engaged in heavy physical labor, a costoclavicular joint appears between the first rib and the collarbone at the site of the ligament of the same name. In individuals with highly developed muscles, full extension of the elbow joint is impossible, which is associated with excessive development of the olecranon process and functional hypertrophy of the forearm flexors. With insufficiently developed muscles, not only full extension is possible, but also hyperextension in the joint, usually in women. Joint mobility in women is slightly greater than in men. The range of motion in the small joints of the hand and fingers is especially large.

X-ray anatomy of the joints of the upper limb

On x-rays (see Fig. 28) of the upper limb, the joints are identified 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 lower limb girdle

Articulations of the pelvic bones can be discontinuous or 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, crossing with it and attaching to the ischial spine. Both ligaments transform the greater and lesser sciatic 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 the fibrous obturator membrane (membrana obturatoria), excluding the superolateral edge, where there remains a small opening that continues into the obturator canal (canalis o bturatorius), through which the vessels and nerves of the same name pass.

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

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

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 promontory of the sacrum to the arcuate line of the iliac bones, then along the crests of the pubic bones and ending at the upper edge of the symphysis.

The small pelvis has two openings - apertures: upper (apertura pelvis superior), limited by the border line, and 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 iliac bones of the pelvis of women are more deployed, the entrance to the pelvic cavity is larger. The pelvic cavity in women resembles a cylinder, in men it resembles a funnel. Cape (promontorium) 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 tuberosities in women are more turned 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 unite to form an acute angle.

For physiological labor, the size of the female pelvis is of great importance. Direct size of the inlet to the pelvis - true, or gynecological, conjugate(conjugata vera, sen conjugata gynecologica) is the distance from the promontory of the sacrum to the most prominent point on the posterior surface of the pubic symphysis and is equal to 11 cm. Transverse diameter(diameter transversa) the entrance to the pelvis is 12 cm. This is the distance between the most distant points of the border 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 pelvic outlet and is equal to 9 cm. During childbirth, it increases to 11-12 cm.

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 - lead And casting In addition, circular rotation is possible. The depth of the glenoid cavity increases due to the cartilaginous acetabular labrum (labrum acetabuli), bordering the edge of the acetabulum. Above the acetabular notch

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

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

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

Rice. 43. Hip joint, right:

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

the strong transverse ligament of the acetabulum is thrown over (lig. transversum acetabuli). Inside the joint there is an intraarticular 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 in the back, not reaching the intertrochanteric crest. Fibrous fibers of the capsule form a circular zone around the femoral neck (zona orbicularis). The joint capsule is strengthened by extra-articular ligaments: the iliofemoral ligament (lig. iliofemorale) starts from the inferior 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 ramus of the pubis to the lesser trochanter.

Knee-joint

Knee-joint(articulatio genus)(Fig. 44) has the largest articular surfaces; This is a complex joint. The condyles of the femur and tibia and the patella take part in its formation. According to the shape of the articulating surfaces, the knee joint is condylar (articulatio bicondylaris). Movements occur around two axes: frontal - bending And extension and vertical (with a bent knee) - pronation And supination. Inside the joint cavity are the medial and lateral menisci (meniscus medialis et lateralis), consisting of fibrous cartilage. Both menisci are connected anteriorly by the transverse knee ligament (lig. transversum genus). The anterior and posterior cruciate ligaments lie within the fibrous capsule of the joint. (lig. cruciatum anterius et posterius). The anterior one starts from the lateral condyle, goes down and inward, and attaches to the anterior intercondylar field. The posterior cruciate ligament extends outward from the medial condyle of the femur and attaches to the posterior condylar field of the tibia. The joint capsule is strengthened by ligaments: fibular collateral ligament (lig. collaterale fibulare) goes from the lateral 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 tibial condyle

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

5- patellar ligament;

b - after opening the joint cavity: 1 - pterygoid fold; 2 - lateral meniscus; 3 - fibrous membrane of the joint capsule; 4 - synovial membrane; 5 - suprapatellar bursa; 6 - posterior and 7 - anterior cruciate ligaments; 8 - infrapatellar synovial fold; 9 - medial meniscus; 10 - patella;

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

bones superior and lateral to the joint capsule; arcuate popliteal ligament (lig. popliteum a rcuatum) starts from the lateral condyle of the femur and is part of the oblique ligament. Patellar ligament (lig.patellae) comes from the top of the patella and attaches to the tibial tuberosity. On the sides of this ligament are the medial and lateral suspensory 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 anterosuperior median and 8 paired ones - 4 each in front and behind: anterosuperior and anterioinferior, posterosuperior and posteroinferior (medial and lateral). In the knee joint there are a number of mucous bursae (Fig. 45): subcutaneous prepatellar (b. subcutaneaprepatellaris), subfascial prepatellar (b. subfascialis prepatellaris), subtendinous prepatellar (b. subtendinea prepatellaris), deep under-

Rice. 45. Synovial (mucous) bursae of the knee joint filled with dye (photo from the specimen): 1 - fragments of the joint capsule; 2 - suprapatellar bursa; 3 - quadriceps tendon; 4 - patella; 5 - patellar ligament; 6 - joint cavity surrounded by a synovial membrane; 7 - medial meniscus; 8 - tibial collateral ligament; 9 - tendon of one of the posterior thigh muscles; 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 muscle tendons.

Shin joints

Both bones of the leg in the proximal region 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 tibia 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 along the edge of the articular surfaces of the bones. The capsule is strengthened on the sides by ligaments: medial (deltoid) (lig. collaterale mediale; lig. deltoideum), anterior and posterior talofibular (ligg. talofibulares anterius et posterius) and calcaneofibular (lig. calcaneofibulare).

Intertarsal joints(articulationes intertarsae) formed between adjacent tarsal bones. These include talocaleonavicular joint(articulatio talocalcaneonavicularis),transverse tarsal joint(articulatio tarsi transversa),calcaneocuboid joint(articulatio calcaneocuboidea),sphenodvicular joint(articulatio cuneonavicularis).

Tarsometatarsal joints(articulationes tarsometatarsales) formed by the bones of the tarsus and metatarsus. They are flat and include the following joints: between the medial cuneiform and first metatarsal bones, between the intermediate and lateral cuneiform bones and the II-III metatarsal bones, between the cuboid bone and the IV-V metatarsal bones. The joints are strengthened by 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. Based on the shape of the articular surfaces, these joints are classified as spherical, but mobility in them 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 trochlea - the articular surface of the ankle joint;

7- transverse tarsal joint; 8 - scaphoid bone; 9 - tarsometatarsal joints;

b - view of the foot from the medial side: 1 - dorsal tarsometatarsal ligaments; 2 - ligaments between the bones of the tarsus (sphenoid-scaphoid); 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-like shape.

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

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

The joints of the lower limb vary 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 rest on the entire foot, but on its outer edge. The shape of the foot may depend on the profession. People engaged in heavy physical labor have wide and short feet; for people not engaged in hard work, it is narrow and long. The foot has a vaulted structure, performing supporting and spring functions. There are 2 foot shapes: arched and flat. The arched structure of the foot provides a springing effect when walking and is supported by 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

Radiographs of the joints of the lower limb reveal the bony articular surfaces delimited by the joint space. The thickness and transparency of the latter, depending on the condition of the cartilage, may change with age.

Questions for self-control

1.With what joints does the clavicle connect 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 structured? Give a description of each of the joints that make it up.

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

5.What is the carpometacarpal joint of the thumb formed by? What movements occur in this joint?

6.What types of joints 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 for 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 CONNECTIONS

The bones of the skull are articulated in different ways: the bones that form the vault are articulated through fibrous joints - sutures, and the base of the skull is articulated through cartilaginous joints, the synchondrosis 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, the arch and the base are distinguished. On the arch, 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 eminence - frontal tubercle

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

Both the external and internal bases of the skull are penetrated by a large number of holes, channels, and crevices in which vessels and nerves are located that connect the brain with the body as a whole.

At 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 of the vault, and pterygopalatine- continuation of the infratemporal deep, 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, respectively, of the eye and associated structures and the olfactory organ. 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 classified as the passive part of the musculoskeletal system.

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 collapsing, which is a very painful and dangerous process. In the human body, joints play a triple role: they help maintain body position, 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 coupling of others. In addition, there are non-bone tissues that protect the joint and soften interosseous friction. The structure of the joint is very interesting.

Main elements of the joint:

Joint cavity;

Epiphyses of bones forming a joint. The epiphysis is a rounded, often widened, end section of a tubular bone that forms a joint with the adjacent bone through the articulation of 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 softens their friction.

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

The joint capsule is a sleeve-like fibrous layer that envelops the joint. It gives bones stability and prevents them from moving excessively.

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

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

A joint is an amazing natural mechanism for the movable connection of bones, where the ends of the bones are connected in the articular capsule. Bag the outside is made up of fairly strong fibrous tissue - this is a dense protective capsule with ligaments that help control and hold the joint, preventing displacement. The inside of the articular capsule is synovial membrane.

This membrane produces synovial fluid - the lubricant of the joint, a viscoelastic consistency, which even in a healthy person does not have much of, but it occupies the entire cavity of the joint and is capable of performing important functions:

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

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

3. Acts as a shock absorber and shock absorber.

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

Synovial fluid a healthy joint has all 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 fully perform their functions and allows you to lead an active life.

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

The ends of the bone joints are covered by an elastic thin layer of smooth substance - hyaline cartilage. Articular cartilage does not contain blood vessels or nerve endings. Cartilage, as mentioned, receives nutrition from the synovial fluid and from the bone structure located under the cartilage itself - the subchondral bone.

Cartilage mainly acts as a shock absorber - it reduces pressure on the mating surfaces of bones and ensures smooth sliding of bones relative to each other.

Functions of cartilage tissue

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 arranged connective tissue fibers - the main substance of cartilage, which are formed by special compounds - glycosaminoglycans.
It is the glycosaminoglycans, connected by protein bonds, that form larger structures of cartilage - proteoglycans - that are the best natural shock absorbers, since they have the ability to restore their original shape after mechanical compression.

Due to its special structure, cartilage resembles a sponge - absorbing fluid in a calm state, it releases it into the articular cavity under load and thereby additionally “lubricates” the joint.

Such a common disease as arthrosis upsets the balance between the formation of new and the destruction of 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 irregular, and begins to grow away from the cartilage. This limits movement and causes joint deformation. The joint capsule thickens and becomes inflamed. Inflammatory fluid fills the joint and begins to stretch the capsule and articular ligaments. This creates a painful feeling of stiffness. Visually, you can observe an increase in the volume of the joint. Pain, and subsequently deformation of the joint surfaces with arthrosis, leads to stiff 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.

According to their shape, the articular surfaces of the bones are compared with geometric figures and, accordingly, joints are distinguished: spherical, ellipsoidal, trochlear, saddle-shaped, cylindrical, etc.

Joints with movement

. Shoulder joint: the articulation that provides the greatest amplitude of movement of the human body is the articulation of the humerus with the scapula using the glenoid cavity of the scapula.

. Elbow joint: the connection of the humerus, ulna and radius bones, allowing rotation of the elbow.

. Knee-joint: a complex articulation that provides flexion and extension of the leg and rotational movements. At the knee joint, the femur and tibia articulate - the two longest and strongest bones, on which, together with the patella, located in one of the tendons of the quadriceps muscle, almost the entire weight of the skeleton presses.

. Hip joint: connection of the femur with the pelvic bones.

. 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 ensures the movement of the lower leg and foot, but also maintains the concavity of the foot.

The following main types of joint movements are distinguished:

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

The human hand contains: 27 bones, 29 joints, 123 ligaments, 48 nerves and 30 named arteries. We move our fingers millions of times throughout our lives. 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 articular cavity of the scapula.

Hip joint

This joint experiences a lot of stress, so it is not surprising that its lesions occupy first place in the general pathology of the articular apparatus.

Knee-joint