Anatomical structure of the feet. Skin and foot structure

Foot - the distal part of the lower, performing a support function when moving. The upper part of the foot, which a person sees when looking under his feet, is called the back. The lower part in contact with the horizontal support - the foot (sole).

The specific anatomy of the foot is due to the phylogenetic development of evolutionary adaptive mechanisms associated with bipedalism.

The foot as part of the human skeleton

Humans are the only species with a complex arched foot structure.

Also, an adaptation to upright walking are such features of the foot as:

• shorter and more massive finger bones forced to withstand a constant load;
• long elongated predigital Part;
• significantly less flexibility and mobility of the joints compared to a brush;
• high bone density, dense skin and fatty layer to protect bones and joints from injury;
• abundance and high density of nerve endings, allowing you to respond to information about the environment and appropriately adjust the nature of the movement.

Physiological features and functions of the foot

Physiology and excessive stress on the feet is the cause of arthrosis: this is the price that a person has to pay for the benefits of upright walking. It is natural that people who are overweight and have a profession associated with the need to stay on their feet for a long time and at the same time walk a little suffer from arthrosis most often.

The constituent elements of the anatomy of the foot are the bone structure (support frame), the connecting elements - the joints and ligaments, and the muscles that provide foot mobility.

The foot of mammals and humans in comparison

The occurrence of a structural and functional disorder in any group of elements negatively affects the others.

The main functions of the foot are:

• support during movement;
• leveling body shocks during running, physical work and exercises (provided by a vault), which protects bones and visceral organs from injury during movement;
• help in adjusting the postures and position of body parts when walking upright.

human foot bones

The foot integrates the following departments:

• tarsus(back part connected to the lower leg), the tarsus consists of 5 bones;
• metatarsus(the middle part, forming an elastic arch), includes 5 bones;
• finger phalanges, include 14 bones.

Thus, the foot is formed 26 bones, and each bone has its own name.

Most people also have 2 small sesamoid bones. In rare cases, the foot includes 1-2 additional, anatomically not provided bones, which often cause problems with the health of the foot to their owners.

Tarsal bones

The talus is the highest bone in the foot and its upper side forms the ankle joint:

• Bone does not have attached tendons or muscles.
• It has 5 articular surfaces, on which a layer of hyaline cartilage is located.
• Also, the heel has many articular surfaces (6 pieces), multiple ligaments are tied to it, the weakening of which is often associated with the formation of flat feet.
• The Achilles tendon is attached to the convex back.

Talus of the foot

Scaphoid forms the inner part of the foot, palpating the joint, the doctor determines the degree of flat feet:

• Participates in the formation of the anatomical vault.
• Connected by a joint with the talus.
• Three sphenoid bones are attached to it in front.
• The sphenoid bones at their proximal ends have articular surfaces for connection with the first three metatarsals.

Cuboid included in the upper tarsal part of the inner side.

Navicular bone of the foot

Metatarsal or metatarsal bones

Despite the fact that these five tubular bones differ in diameter and length (the thickest and shortest is the first bone, the most elongated is the second), their structure is identical.

They include:

• head;
• body;
• base.

The bodies of these bones have the form of a pyramid with three ribs, and the heads have rounded front ends. The articular surfaces on the heads of the metatarsal bones are associated with the lower phalanges of the fingers, and on the bases of the bones - with the anterior tarsal bones.

Metatarsal bones of the foot

Phalanges of fingers

By analogy with the hand, the big toes have only the proximal (lower) and distal (upper) phalanges, and the remaining fingers have three phalanges (intermediate, proximal and distal), connected by movable joints. These are generally small and thin tubular bones.

Sometimes the two phalanges of the little toes of the foot grow together (which is not a pathology).

The phalanges of the feet are noticeably shorter and thicker than those of the hands. This is due to the fact that the foot does not require flexibility and the development of fine motor skills, like fingers, but strength and the ability to withstand prolonged loads are required.

Phalanges of fingers

Like the metatarsals, the bones of the phalanges of the toes are protected by a rather scarce amount of soft tissue, so they are easily palpable, especially in lean, wiry people.

Two such bones are located in the thickness of the tendons of the thumbs at the junction of the metatarsal bones with the proximal phalanges of the thumbs. They affect the severity of the arch of the metatarsus.

On x-rays of the foot, they look like grains of foreign matter in the thickness of the ligaments. Sometimes these bones have a bifurcated shape (this can be both a given from birth and a consequence of an injury).

Sesamoid bones

Additional or supernumerary bones

Most common external tibia(12% of the population, almost twice as common in women), which is connected to the scaphoid cartilage or ligaments. Its dimensions are variable; in people with a large bone, it sticks out strongly down, which entails constant rubbing of this area with shoes. Sometimes it is found in professional athletes.

For those who have found an external tibia, it is recommended to wear arch supports or special insoles (for large bones, also orthopedic shoes). Treatment of the consequences that the bone caused is determined by a particular case of the clinical picture.

In 7% of the population triangular bone. On x-ray, it can be confused with a fracture. An uneven border line and clearly focused pain indicate a fracture, a smooth even border line indicates the presence of a triangular bone.

Diagram of foot bones with captions

Features of joints, ligaments and cartilage

Joint complexes are responsible for the mobility of the foot - intertarsal, tarsal-metatarsal, metatarsophalangeal and interphalangeal.

Intertarsal joints

They realize the connection between the bones of the tarsus.

The ankle joint is the highest point of the foot:

subtalar joint has the shape of a cylinder, formed by the back of the talus and calcaneus, there are short ligaments.

The spherical talocalcaneo-navicular joint. The axis formed by this pair of joints serves as the center of supination and pronation of the foot.

Tarsus-metatarsal joints

The joints of this group connect the parts of the tarsus with each other and with the bones of the metatarsus. Most of them have flat articular surfaces and very little mobility.

In addition to the joints, numerous ligaments are responsible for the stability of this part of the foot, most of which are attached to the heel and outer parts of the foot. The largest of them connects the calcaneus to the proximal parts of all tarsal bones (except those associated with the thumbs).

Tarsus-metatarsal joints of the foot

Intermetatarsal joints

They have a flat surface and connect the sides of the metatarsal bones.

Ligaments serve as a connection:

• plantar;
• interosseous;
• rear.

Metatarsophalangeal joints

Formed by the posterior parts of the proximal phalanges and the rounded heads of the metatarsal ossicles. Despite their rounded shape, these joints have rather little mobility (but still superior to the tarsal-metatarsals).

In older people, deforming is quite common, which usually manifests itself as on the inner side of the proximal phalanx of the thumb (thus, the metatarsophalangeal joint is affected).

Metatarsophalangeal joints of the foot

The anatomy of the bones of the foot almost repeats the hand and consists of the following elements:

• tarsus;
• heel and instep;
• five pluses;
• 14 phalanges of fingers (2 for the first, but 3 for the rest).

Nevertheless, the task of the foot, unlike the hand, is not grasping, but mainly supporting, and this is reflected in its structure.

The bones are rigidly interconnected and have an elastic dome-shaped structure, which is preserved due to their special shape, as well as muscles and ligaments. The plantar ligaments pull together the edges of the foot from below, forcing it to arch upwards in the form of an arch. This structure makes the foot a spring-loaded shock absorber that absorbs pressure surges that act on the legs and spine when moving.

Description of the components

The skeleton of the foot has 52 bones in its structure. The joints are small and have a rather complex structure. The ankle connects the foot to the lower leg, and the small bones of the lower leg are also connected by small joints to each other.

The bases of the phalanges of the fingers and 5 metatarsal bones are held together by the joints of the same name. And each finger consists of 2 interphalangeal joints that hold small bones together. The tarsals are connected to the central skeleton of the foot by the metatarsal and tarsal joints. They are fixed with a long ligament of the sole, which prevents the occurrence of flat feet. The bones of the human foot are made up of three parts: the tarsus, metatarsus, and toes. The composition of the tarsus: behind it is formed by the talus and calcaneus, and in front - by the scaphoid, cuboid and three sphenoid bones. The talus is placed between the leg bone and the calcaneus, playing the role of an adapter from the lower leg to the foot. Along with the talocalcaneal-navicular joint, the joint connects the tarsus and the back. With the help of them, the possibilities of movement of the foot increase to 55 degrees.

Movement of the foot relative to the lower leg is provided by two joints:

1. The ankle joint itself is formed by two tibia and talus bones. It allows you to raise and lower the forefoot.
2. The subtalar joint is located between the talus and calcaneus. It is necessary for tilting from side to side.

A common injury is an ankle sprain that occurs when the leg is twisted, when a person changes movement abruptly, or on uneven ground. Ligaments on the outside of the foot are usually injured.

The calcaneus refers to the back of the lower part of the tarsus. It has a long, flattened configuration and is the most impressive in size in comparison with others and consists of a body and a protruding posterior calcaneal tubercle. The heel has the articulations necessary to align with the talus above and in front with the cuboid. Inside on the calcaneus is a protrusion that serves as a support for the talus.

The navicular bone is located at the inner edge of the foot. It has joints that connect to adjacent bones.

The cuboid bone is located at the outer edge and connects behind with the calcaneus, inside with the navicular, outside with the sphenoid, and in front with the 4th and 5th metatarsal bones.

The toes are built from phalanges. Similar to the structure of the hand, the thumb is built from two phalanges, and the remaining fingers from three.

Separate the phalanges:

• proximal
• middle,
• distal.

The phalanges of the foot are much shorter than the phalanges of the hand, especially the distal phalanges. It cannot match the mobility of the hand, but the vaulted structure makes it an excellent shock absorber, softening the impact of the foot on the ground. The ankle of the foot has a structure that provides the mobility needed when walking or running.

Each movement of the foot is a complex interaction of muscles, bones and joints. The signals sent by the brain coordinate the work of the musculature, and its contraction pulls in a specific direction of the bone. This results in flexion, extension, or rotation of the foot. Due to the coordinated work of the muscles in the joint, it is permissible to perform joint movement in two planes. In the frontal plane, the ankle does extension and flexion. In the vertical axis, rotation can be performed: slightly outward and inward.

Over the course of a lifetime, each sole hits the ground an average of more than 10 million times. With each step of a person, a force acts on the knee, often 5-6 times the weight of his body. When he steps on the ground, the anterior calf muscles pull on the tendons attached to the top of the foot and lift it up along with the toes. The heel takes the first hit. When the entire foot is lowered to the ground, the bones of the tarsus form a springy arch, distributing the load from the weight of the body as its pressure moves from the heel to the anterior end of the metatarsus and toes. The calf muscles pull on the Achilles tendon, which lifts the heel, lifting it off the ground. At the same time, the muscles of the foot and fingers contract, moving them down and back, due to which a push occurs.

Problematic issues and diseases, from corns to arthritis, are dealt with by a podiatrist - a specialist in the treatment of feet. It also helps correct posture and gait. You can learn about everything that happens with the feet from this specialist: hygienic care, selection of optimal shoes, fungal diseases, heel pain, arthritis, vascular problems, as well as calluses, bones and ingrown nails.

The podiatrist is also aware of the mechanics of leg movement. For example, if one of the two feet is more flattened than the other, there is an imbalance in the body, which is reflected in hip pain, and inflexibility of the big toe can affect the functioning of the spine.

What is the role of cartilage?

When studying the bone structure of the leg, it is necessary to pay attention to the cartilage. Thanks to them, the joints are protected from excessive loads and friction. Their articulated ends are covered with cartilage with a very smooth surface, which reduces friction between them and absorbs shock, as a result protecting the joint from damage and wear. The cartilage-covered heads of the bones glide because they are elastic, and the synovial fluid produced by their membrane is the lubricant that keeps the joints healthy. A lack of synovial fluid can limit a person's ability to move. Sometimes cartilage can also harden. In this case, the movement of the joint is severely disturbed, and bone fusion begins. This phenomenon cannot be ignored, otherwise you can lose mobility in the joints.

The Achilles tendon, or calcaneal tendon, is the longest and strongest tendon in the human body. It connects the lower end of the gastrocnemius and soleus muscles to the posterior tubercle of the calcaneus. As a result, the contraction of these muscles pulls up the heel, allowing you to stand on the toe of your foot and push it off the ground as you move.

Characteristic diseases

Like any part of the body, the bones of the foot are not only exposed to external influences, its condition is affected by the age of a person, when the bone structure becomes less strong, and the joints are not so mobile. Consider the most common foot problems.

1. Bursitis of the big toe.

We are talking about inflammation of the bursa in the metatarsus of the phalangeal joint of the first toe. Women suffer from this disease more often than men, the reason is narrow shoes with high heels, which creates increased pressure on the toes. This leads to the development of other problems, such as calluses and corns. Pain and discomfort can be alleviated by wearing comfortable, roomy shoes and using soft padding on the bump to protect it from pressure. In advanced cases, surgery is recommended.

1. Valgus deformity of the thumb.

The disease is manifested by the protrusion of the metatarsus of the phalangeal joint of this finger to the side, which deviates in the opposite direction. Often, but not always, it leads to bursitis and lump formation. Sometimes this problem is passed down through generations and develops already in adolescence. If such a deformity appears only in old age, it is often caused by incipient osteoarthritis.

1. Flat feet.

Flat feet is a thickening of the arch of the foot. Normally, its inner side between the heel and the metacarpophalangeal joints is curved upwards. If it is not expressed, flat feet are observed. This disease occurs in about 20% of the adult population. Often no treatment is required. Only comfortable shoes with a special insole or instep support under the arch of the foot are recommended. For the elderly, special orthopedic shoes are ordered. And only in the most severe cases, the deformity of the foot is corrected surgically.

1. Deforming arthrosis.

A disease occurs due to calcium deficiency, injuries, increased loads, thinning of cartilage tissues and bone tissue occurs. Over time, outgrowths appear - osteophytes, which limit the range of motion. The disease is expressed by severe mechanical pains, which increase in the evening, subside at rest and increase with physical exertion. There are many ways to slow down the progression of these ailments and alleviate their symptoms. These include reducing the load on the affected joint and maintaining its activity. Shoes should be comfortable, well-fitting, with excellent arch support, minimizing shaking as you move.

People should take care of their health. Take small steps that will lead to healing and maintaining bone strength and joint mobility, using moderate physical activity, relaxing massages or various physiotherapy procedures for this. And then health will not let you down and in old age will allow you to maintain an active and active lifestyle.

The anatomical features of the structure of the human foot are unique. To determine how to treat a particular ailment of the lower extremities, you need to know their structure.

Foot bones

The anatomy of the foot includes several elements.

Finger bones

This element of the skeleton has an important task - it ensures proper walking. The toe bone consists mainly of three phalanges. The exception is the thumb (it has two tubular bones). The bone elements themselves have a short part and are connected to the foot by the articular surface of the proximal phalanges.

Metatarsus

The department consists of 5 small bones. The first metatarsus is the strongest. It is thicker than the rest of the elements. Failures in its functioning are often the cause of valgus changes, since salt deposits often appear on the head of this part of the ODA. The second metatarsal bone of the foot is longer than the others. The proximal parts are connected to the elements of the posterior parts of the foot.

Tarsus

The bones of the foot in this department are divided into two groups. The middle is formed by the talus and calcaneus, the far - wedge-shaped, cuboid and navicular. Features of the anatomy of the talus are that it connects the ankle and foot into one and forms a joint. The heel is below the considered element and has a massive body. Often, salt deposits occur on it, which prevent a person from moving normally and bring pain. The cuboid bone forms the outer edge of the foot, and the scaphoid forms the inner edge. The wedge-shaped bone elements are connected to each other and to the metatarsus.

Joints and cartilage

Consider the anatomy of the joints of the foot.

Ankle

One of the most complexly organized joints of the human lower extremities. The bones of the lower leg are connected to the bones of the foot and are securely fixed by a powerful ligamentous apparatus. Thanks to this fastening, the ankle joint can perform various functions - flexion, extension, rotation. Injuries in this area cause severe discomfort, prolonged lameness and swelling. In case of serious damage to the joint, a complex operation is performed under the control of an x-ray.

Intertarsal joints

The structure of the human foot is formed by several elements.

rammed

The subtalar joint is formed by the calcaneus and talus bones. The joint capsule is reinforced with ligaments - lateral, medal - and covered with smooth cartilage.

wedge-shaped

It has a complex structure, consisting of several elements - the sphenoid and scaphoid bones of the foot. The joint does not move, as it is fixed by the dorsal ligamentous apparatus of the sole into one capsule, which is attached to the cartilage bases (hence the name of the element).

Calcaneocuboid

The shape resembles a saddle and performs the only function - rotation. The articulation is reinforced by plantar ligaments, is part of the transverse connection of the tarsal bones.

talocalcaneal-navicular

Formed from parts of the same name. In terms of functionality, the talocalcaneal-navicular joints are rotational. The capsule is attached to the edge of the cartilaginous tissue that covers the surface of the formed articulation.

Tarsus-metatarsal joints

Connects the bone elements responsible for the structure of the bones of the foot. In total there are three parts that form the syndesmosis. The first joint resembles a saddle in shape (saddle-shaped), the rest have a flattened structure. Fixed articulation metatarsal, plantar and dorsal ligaments.

Intermetatarsal

A small element fixed by the ligamentous apparatus of the metatarsal bones.

Metatarsophalangeal

Responsible for flexion and extension of the toes, differ in spherical shape. Each element has its own joint capsule.

Interphalangeal joints

Located between the phalanxes. They are fixed by a collateral ligamentous apparatus. Participate in the movement of the fingers.

Arch of the foot

Carries out several functions: depreciation when jumping and running; support - hold the weight of the body when a person is in an upright position.

The anatomy of the structure of the arch of the foot consists of a transverse and longitudinal part and has an arcuate device, due to which a person, when walking, relies on the metatarsus and heel. In case of problems with ligaments and muscles, the foot takes on a more flattened shape, as a result of which the spine and nearby joints may suffer, which take on some of the functions of maintaining the load and upright posture.

Foot muscles

Foot movements are provided by several muscle groups. The short extensor located on the anterior surface is responsible for finger flexion. For a large one, there is a separate movement scheme. Also, an individual muscle element forms the abduction and flexion of the little finger. The plantar muscles are responsible for the formation of the arch of the foot, the dorsal muscles are responsible for the motor features of the digital phalanges. The latter work while walking or running.

Muscle tissue is attached by tendon ends above or below cartilage.

Tendons and ligaments

These elements hold the joints together and maintain the arched appearance of the foot during loads and movements. They provide strong fastening of muscle tissue, give mobility to the joint and lower limbs. If the ligaments and tendons are damaged, a person may experience severe pain. With a long course of the disease, it can become chronic. The injury also causes inflammation, which is called tendonitis.

blood supply

The blood flow to the feet brings the upper gluteal, posterior tibial and dorsal artery coming from the knee. They are divided into several small vessels. In the opposite direction, blood and decay products are carried away by the veins. One of the vascular elements - the great saphenous vein - begins in the region of the first finger. Often, the legs suffer as a result of the development of diseases (atherosclerosis and varicose veins), which leads to insufficient blood supply and various ailments.

innervation

Nerves control the muscles of the lower leg and send impulses to them. The anatomy of the nervous system of the lower extremities is arranged by the posterior and superficial peroneal, as well as the tibial and sural nerves. With excessive squeezing of the innervated area, its numbness and tingling sensation occur with a violation of the functions performed.

The anatomy of the bones of the foot has a complex structure and is rich in small capillaries, which is necessary for the movement of the feet. Thanks to its anatomical features, a person can move sideways, run, jump and adapt to different surfaces while walking. The foot can withstand a tremendous load, as a result of which it must be protected. If there is a risk of leg injury, be sure to strengthen large muscles with protective equipment.

Human evolution has made the foot a unique and complex mechanism that performs spring and balance functions, providing shock mitigation during movement.

Thanks to the limbs, a person got the opportunity to move, keep balance, and resist movement.

There are 26 bones in the foot and all of them are connected into one mechanism by ligaments and joints.

In addition, there is a huge amount of muscle tissue and tendons.

Bones

The foot and hands are similar in structure. Anatomy divides the foot into the following bone sections:

tarsal

Includes 7 bones. The most bulky are talus and heel. The talus is located between the lower leg and refers more to the ankle. This includes:

• - club-shaped;
• - scaphoid;
• - sphenoid bone.

Metatarsus

This is a collection of five bones resembling tubules in shape. This department is average and is responsible for the functioning of the fingers and the correct location of the arch. Bones ending in joints lead to the beginning of the fingers.

Distal

It has 14 bones. Each finger has 3 bones, except for the thumb, which has only two. Between the bone formations are joints for mobility.

Thanks to this zone of the foot, the human body keeps balance and can move. Interestingly, in case of loss of hands, the toes perform a replacement function.

The joints are located between the bones. In addition, the foot contains muscles, ligaments, nerves, and blood vessels.

How are the bones located?

Bones require more detailed consideration, since they are the main component of the foot.

The heel bone is the most powerful

It is located in the back and carries a huge load. Despite the fact that this part has nothing to do with the ankle, it plays a large role in the distribution of pressure. The shape of the calcaneus resembles a triangle in three dimensions with a long axis.

The role of the connector between the calcaneus and the talus is performed by the joints. A strong connection of these two bones is necessary to give the foot a normal shape. The back of the bone holds the Achilles tendon. This place can be found on a small ledge. And the lower part is a support when walking on the surface of the earth.

On the front part, you can find a tubercle where the scaphoid bone and the joint are connected. On the surface, you can see many protrusions and vice versa - depressions. These are the places where blood vessels, muscles, nerves, ligaments are attached.

The talus is several times smaller than the calcaneus

But massive and is part of the ankle. She is turned to the heel. It mainly consists of cartilage and, surprisingly, it does not hold anything other than ligaments. Its surfaces, consisting of 5 pieces, are lined with a thin layer of hyaline cartilage.

This bone is made up of the following parts:

Despite the power of the bone, it is often injured or ill.

cuboid

You can find it on the outside of the foot at the outer edge. Located behind the 4th and 5th metatarsals. The shape is a cube, hence its name. Behind comes into contact with the calcaneus, and that is why it has a saddle shape and calcaneal process.

Scaphoid

It is located directly on the foot at the inner edge.

Its ends are flattened, the upper part can bend, and the lower part is sunken.

Thanks to the joints, it interacts with the talus and serves as a foot shaper.

wedge-shaped

Consists of three bones:

• - medial, it is the largest;
• - intermediate, smallest;
• - lateral - middle.

They are all small and located quite close to each other. They have the metatarsal bones in front and the navicular bones behind. The entire system is strong and rigid, forming a solid foundation for the foot.

metatarsal bones

They are curved tubes. They have the same structure and carry out similar functions in both young and adult years. The bends of the bones give the arch the desired position. If you look at the surface, then it is characterized by tuberosity, due to the connection of ligaments, joints and muscles.

phalanges

The same as on the fingers. The difference is only in size. The thumb is assembled from 2 phalanges, and the shape is much thicker due to the resulting load when walking. The rest consist of three phalanges and are much thinner and shorter.

joints

What are joints made of?

The feet are distinguished by the presence of a large number of joints that play a reducing role between the bones. If we compare them in size, then the largest is the ankle joint, which connects three large bones together. This allows a person to raise and lower the foot, to make rotational movements. The remaining joints are much smaller, but in fact their function is similar. They give you the flexibility you need.

Let's say a little about the ankle joint. It includes a large talus and two smaller tibias that include the ankles. The edges of the joint are attached with strong ligaments, and it is securely connected to the cartilage.

A huge role is played by the transverse or subtalar joint. It is inactive, but connects as many as three bones - the scaphoid, talus and calcaneus. For more reliable fixation, participation in the connection of ligaments is provided.

The subtalar joint is helped to form the arch by the cuboid and heel joints. Sometimes such a connection is called the Greek cavity, and in medicine it was called the talonavicular joint.

One of the most important joints is the metatarsophalangeal. They take part in every movement of the human body.

The least significant are the joints on the navicular and sphenoid bones.

Bundles

In first place in importance is the plantar ligament. It originates from the calcaneus and ends at the origin of the metatarsal bones.

The ligament is distinguished by a large number of branches that carry the fixing function of the longitudinal and transverse arches.

Such a connection is responsible for the correct condition of the arch throughout a person’s life.

Smaller ligaments are needed to strengthen the skeletal system and joints. Thanks to them, the human body is able to maintain balance and load during movements.

muscles

The foot can move only with the help of muscles. They are everywhere - in the area of ​​​​the foot, lower leg and ankle. The muscular structure of the lower leg provides movement of the feet during walking and in an upright position.

The anterior part consists of the extensor longus muscle group and the tibialis muscle. Thanks to them, the phalanges on the legs can be bent and unbent.

The long and short fibulas provide lateral flexion of the foot and pronation.

A very bulky muscle group is located in the back. These muscles are made up of several layers. This includes the following muscles:

• triceps, including gastrocnemius and soleus;
• finger flexor;
• plantar;
• tibial (partial).

The sole during the work of this muscle group is bent with the help of the Achilles tendon. And muscle tissue helps with bending and unbending the fingers.

For the movement of four fingers, not taking into account the big one, the extensor of the short type, which belongs to the dorsal muscle group, is responsible. Small muscles on the foot allow it to perform the functions of abduction, flexion.

Vascular and nervous systems of the foot

Blood

In order for blood to flow to the feet, tibial arteries are provided in front and behind. They stretch along the very foot on the sole. Small connections and circles depart from these large arteries.

When the foot is damaged, one of the circles is disrupted, but the others continue to provide the necessary blood flow to the limbs.

The veins on the back side are responsible for the outflow. They look intertwined and provide blood to the great and small saphenous veins in the lower leg.

Nerves

They form an integral part of the normal functioning of the human foot. They are responsible for sensations:

• - pain;
• - vibrations;
• - touch;
• - cold or warm.

Nerve signals, leaving the CNS along the gastrocnemius, peroneal, superficial and tibial nerves, reach the spinal cord and are processed there.

Nerves transmit a signal to the muscles, being essentially reflexes - voluntary or involuntary (independent of human will). Involuntary include the work of the glands (sebaceous and sweat), vascular tone.

As for the skin, there are several zones on the foot that differ in density, structure, and elasticity. For example, the leather of the sole is high density, while the heels are thick. Initially, the skin of the palms and feet are the same, but over time and with increasing loads, additional layers appear. The back of the foot is smooth and elastic, with nerve endings.

Drawing a conclusion, we can say that nature has done everything so that the foot can withstand tremendous pressure.

Foot diseases

The foot is regularly subjected to loads, either static or impact. Injuries are common for her. Almost always accompanied by pain, an increase in some of the epiphyses, swelling, curvature. You can identify the pathology on an x-ray.

Arthrosis

This is a disease in which cartilage loses its elasticity. Often this disrupts metabolic processes. There is pain, crunch, swelling.

Causes of arthrosis:

• - infectious diseases;
• - allergies;
• - systemic diseases - lupus erythematosus, scleroderma;
• - tuberculosis;
• - syphilis;
• - dislocation or injury.

Often you can find arthrosis of the first toe.

The disease develops in 3 stages:

1. At first, pain occurs, but disappears after rest. Sometimes the deviation of the thumb becomes noticeable. There is a crunch when moving.
2. To dull the pain, painkillers and anti-inflammatory drugs are taken. The finger is already bent strongly and it becomes impossible to pick up shoes.
3. The pain does not go away even when taking analgesics. The deformity extends to the foot, there is a problem with walking.

Arthrosis also strongly loves the ankle, deforming the joint and affecting the cartilage.

This disease is treated conservatively only at an early stage. Then you will need surgical intervention - arthroplasty, resection, arthroplasty.

flat feet

There are congenital or acquired flat feet. Reasons for the appearance:

• - excess weight;
• - heavy loads;
• - diseases of the nerve endings;
• - injuries;
• - Wrong shoes
• - transferred rickets or osteoporosis.

Flat feet come in two forms:

1. Transverse - with a decrease in the height of the arch, when the heads of the metatarsal bones are in contact with the ground.
2. Longitudinal - that is, the entire foot has contact with the ground. Increased fatigue in the legs, pain.

Arthritis

A joint disease that affects the entire human body. There are primary and secondary arthritis. The causes of the appearance are the same as with arthrosis. Symptoms include:

• - pain;
• - deformity of the leg;
• - swelling, redness;
• - fever, rash, fatigue.

Treatment methods depend on the underlying cause of the disease and can be physiotherapy, medication, manual, etc.

Clubfoot

As a rule, it occurs from birth. The reason is a subluxation of the ankle joint. Acquired clubfoot is the result of trauma to the lower extremities, paralysis, paresis.

Disease prevention

Preventing the development of diseases is much easier than treating. Prevention includes:

• performing special strengthening exercises;
• sparing sports - cycling, skiing, swimming;
• wearing comfortable shoes made from natural materials;
• walking on pebbles, sand, grass;
• the use of special orthopedic insoles;
• resting the legs.

In total, there are 26 bones in the foot + from 2 sesamoid bones (minimum). For this reason, the foot is deservedly considered the most complex anatomical formation, and, along with the hand, has earned a separate orthopedic subspecialty.

The bones of the foot, ossa pedis, are divided into three sections: the tarsus, tarsus, which forms the posterior section of the foot skeleton, the metatarsus, metatarsus, is its central section and the fingers, digiti, representing the distal section.

Foot bones.

BONES OF THE TARSAL. The tarsal skeleton includes 7 bones. It is customary to distinguish two rows in it: the proximal, consisting of two bones (talus and calcaneus), and the distal, including four bones (three sphenoid and cuboid). Between these rows of bones is the navicular bone. The bones of the proximal row are located one above the other: below - the calcaneus, calcaneus, above - the talus, talus. Because of this arrangement, the talus has a second name - the supracalcaneus.

Talus, talus, has a head, neck and body. The head, caput tali, is directed forward, has a spherical articular surface for articulation with the navicular bone, facies articularis navicularis. A short narrowed part of the bone departs from the head - the neck, collum tali, connecting the head to the body. The protruding part of the body with three articular surfaces is called the block, trochlea tali. Of these three articular surfaces, the upper, facies superior, serves to articulate with the tibia. Two lateral surfaces are ankle, fades malleolaris medialis et lateralis. To the side of the latter is the lateral process, processus lateralis tali. Behind the block of the talus, a rough posterior process protrudes, processus posterior tali. It is divided by the groove of the tendon of the long flexor of the big toe, sulcus tendinis i.e. flexoris hallucis longi, into two tubercles. On the lower surface of the body there are two articular surfaces separated by a wide groove, sulcus tali: posterior, facies articularis calcanea posterior, and anterior, facies articularis calcanea anterior.

Talus.

calcaneus, calcaneus, is the most massive of the bones of the foot. It distinguishes the body, corpus calcanei, ending behind the calcaneal tuber, tuber calcanei; on the medial side of the body there is a protrusion - the support of the talus, sustentaculum tali. On the upper surface of the body are the posterior and anterior articular surfaces, corresponding to those on the talus, facies articularis talaris posterior et anterior, while the anterior, like the talus, is divided into two parts, one of which (medial) extends to the sustentaculum tali. The anterior and posterior articular surfaces are separated by a wide rough groove of the calcaneus, sulcus calcanei. This groove, together with the groove of the talus, forms a depression - the tarsal sinus, sinus tarsi, which opens on the body of the bone from the lateral side. Sustentaculum tali departs from the body of the calcaneus from the medial side. It supports the head of the talus. On its lower surface there is the already mentioned groove, sulcus tendinis t. flexoris hallucis longi, which is a continuation of the groove of the same name on the talus. On the lateral side of the calcaneus is a small process - the fibular block, trochlea peronealis. Under it passes the groove of the tendons of the peroneal muscles, sulcus tendinis tt. peronei. At the anterior end of the body there is another articular platform for articulation with the cuboid bone, facies articularis cuboidea.

Calcaneus.

Scaphoid, os naviculare, so named because its shape resembles a boat, the concavity of which faces the head of the talus. The concavity is occupied by the articular surface for the talus. The convex side of it is directed to the three sphenoid bones. This surface is divided by ridges into three unequal articular areas for these bones. On the lateral side there is an articular surface for the cuboid bone. At the medial edge of the bone is tuberosity, tuberositas ossis navicularis, to which the tendon of the posterior tibial muscle is attached.

Scaphoid.

Three cuneiform bones, ossa cuneiformia, are part of the distal row of the tarsus and lie, as indicated, anterior to the scaphoid. All three bones justify their name in shape, but differ from each other in size and position.

Internal, median, external cuneiform bones.

Os cuneiforme mediale - the largest of the three named bones, with a wedge point facing the rear of the foot, and with an expanded base - to the sole. It has three articular surfaces: posterior (depressed) - for articulation with the navicular bone, anterior (flat) - for articulation with the first metatarsal bone, and lateral - for articulation with the sphenoid bone.

Os cuneiforme intermedium - the smallest of the three sphenoid bones, and the shape most corresponding to the wedge. Unlike the previous bone, its base faces the rear of the foot, and the sharp edge faces the sole. It has articular platforms for the surrounding bones: behind - for the scaphoid, in front - for the second metatarsal, from the outer and inner sides - for the neighboring sphenoid.

Os cuneiforme laterale - compared to the previous ones, it is medium in size, has a regular wedge-shaped shape, the base is facing the rear of the foot, and the top is the sole. It has the following articular areas: behind - for os naviculare, in front - for os metatarsale III, on the inside - for os cuneiforme intermedium and os metatarsale II, on the outside - for os cuboideum.

Internal, median, external cuneiform and cuboid bones.

Cuboid, os cuboideum, is located on the lateral edge of the foot between the calcaneus at the back, the IV and V metatarsal bones at the front, therefore there are two articular platforms on its front surface, and one on the back. The inner surface is in contact with the lateral sphenoid and scaphoid bones, therefore, it bears two articular surfaces for articulation with them. Moreover, the first of them (for the lateral sphenoid bone) is large in size, and the posterior one is small, sometimes absent. The lateral edge of the bone is free from articular surfaces. On the plantar side there is a tuberosity, tuberositas ossis cuboidei, anterior to which there is a groove for the passage of the tendon of the long peroneal muscle, sulcus tendinis musculi peronei longi.

METASUS BONES. The metatarsus, tarsus, consists of five short tubular bones that have a body, corpus, head, caput, and base, basis. The bones of the metatarsus are similar in shape and structure, but differ in size: the first metatarsal bone (located on the side of the thumb) is the shortest and most massive, the second is the longest. The heads of the metatarsal bones are narrowed compared to the bones of the metacarpus, significantly compressed from the sides. The bodies are prismatic, curved in the sagittal plane, convexly facing the rear. The bases of the metatarsal bones articulate with the bones of the distal row of the tarsus and are provided with characteristic articular surfaces. The head of os metatarsale I is divided on the plantar side by a protrusion into two platforms for articulation with the sesamoid bones. On the basis of this bone there is a concave surface for articulation with os cuneiforme mediale. On the side of the sole, there is tuberosity on the base, tuberositas ossis metatarsalis I. The bases of os metatarsale II and III resemble a wedge, with its tip pointing down. The base of os metatarsale IV approaches a cube in shape. On the base of os metatarsale V, on the lateral side, there is a tuberosity, tuberositas ossis metatarsalis V, to which the tendon of the short peroneal muscle is attached.

1st, 2nd, 3rd, 4th, 5th metatarsals.

The bones of the metatarsus and tarsus do not lie in the same plane, but form longitudinal arches, convexly facing upwards. As a result, the foot rests on the ground only with some points of its lower surface: behind the fulcrum is the calcaneal tubercle, in front - the heads of the metatarsal bones. The phalanges of the fingers only touch the area of ​​support. According to the bones of the metatarsus, five longitudinal arches of the foot are distinguished. Of these, the arches I-III do not touch the support plane when the foot is loaded, therefore they are spring-loaded; IV and V - are adjacent to the area of ​​\u200b\u200bthe support, they are called support. Due to the different shape and convexity of the longitudinal arches, the lateral edge of the foot (IV-V arches) descends to the area of ​​support, the medial edge (I-III arches) has a distinct arched shape.

In addition to the longitudinal arches, two transverse arches (tarsal and metatarsal) are distinguished, located in the frontal plane, bulging upwards. The tarsal arch is located in the region of the tarsal bones; metatarsal - in the area of ​​\u200b\u200bthe heads of the metatarsal bones. Moreover, in the metatarsal arch, the support planes touch the heads of only the first and fifth metatarsal bones.

The arches of the foot provide a shock-absorbing function during static loads and walking, and also prevent compression of soft tissues during movement and create favorable conditions for normal blood circulation.

PHALANX TOES. The skeleton of the toes is similar to the skeleton of the fingers of the hand, that is, it consists of phalanges, phalanges digitorum pedis, the number, shape and names of which are the same as on the hand (I toe, hallux, also has only two phalanges). The phalanges of the I finger are thicker, in the remaining fingers their sizes are much smaller, especially the short phalanges are in the IV and V fingers. In the little finger, the middle and distal (nail) phalanges are often fused. The body of the proximal phalanges is much thinner compared to the middle and distal ones, and is close to a cylinder in shape.

On the foot, as well as on the hand, there are sesamoid bones. They are located constantly in the region of the metatarsophalangeal joints of the thumb and little finger, and in the interphalangeal joint of the thumb. In addition to the named sesamoid bones, there are also unstable bones in the tendons of m. peroneus longus et m. tibialis posterior.

FOOT BONE JOINTS

All joints of the bones of the foot, articulationes ossa pedis, can be divided into four groups:

1) articulation between the bones of the foot and lower leg - articulatio talocruralis;

2) articulations between the bones of the tarsus - articulationes subtalaris, talocalcaneonavicularis, calcaneocuboidea, cuneonavicularis, intertarseae;

3) articulations between the bones of the tarsus and metatarsus - articulationes tarsometatarseae;

4) articulations between the bones of the fingers - articulationes metatarsophalangeae and interphalangeae.

ANKLE JOINT. The ankle joint, articulatio talocruralis (supratalar joint), is formed by both bones of the lower leg and the talus. Its articular surfaces are: the articular fossa, which looks like a fork, formed by fades articularis inferior tibiae, fades articularis malleoli medialis (on the tibia), fades articularis malleoli lateralis (on the fibula). The articular head is represented by a block of the talus with its articular surfaces: facies superior, facies malleolaris medialis and facies malleolaris lateralis.

The joint capsule is attached along the edge of the articular cartilage and only recedes in front of it (about 0.5 cm on the tibia, almost 1 cm on the talus). It is free front and back. From the sides, the capsule is stretched and reinforced with strong ligaments. Ligaments that strengthen the joint are located on its lateral surfaces.

The medial (deltoid) ligament, ligamentum mediale, includes four parts: the tibial-navicular part, pars tibionavicular, the anterior and posterior tibiotalar parts, partes tibiotalares anterior et posterior, and the tibiocalcaneal part, pars tibiocalcanea.

On the lateral side, the joint capsule is reinforced by three ligaments. The anterior talofibular ligament, ligamentum talofibulare anterius, runs almost horizontally from the anterior margin of the malleolus lateralis to the anterior margin of the lateral platform of the talus. The calcaneofibular ligament, ligamentum calcaneofibulare, starts from the outer surface of the malleolus lateralis, goes down and back to the lateral side of the calcaneus. The posterior talofibular ligament, ligamentum talofibulare posterius, connects the posterior edge of the malleolus lateralis to the posterior process of the talus.

The ankle joint in shape is a typical block-shaped. It allows movements around the frontal axis: plantar flexion; extension (dorsal flexion). Due to the fact that the talus block is narrower behind, lateral rocking movements are possible with maximum plantar flexion. Movements in the ankle joint are combined with movements in the subtalar and talocalcaneal-navicular joints.

JOINTS OF THE TARSAL BONES. The articulations of the tarsal bones are represented by the following joints: subtalar, talocalcaneal-navicular, calcaneocuboid, cunei-navicular.

The subtalar joint, articulatio subtalaris, is formed by the articulation of the posterior calcaneal articular surface, facies articularis calcanea posterior, on the talus and the posterior talar articular surface, facies articularis talaris posterior, on the calcaneus. The joint is cylindrical, it can move only around the sagittal axis.

The talocalcaneal-navicular joint, articulatio talocalcaneonaviculars, has a spherical shape. It distinguishes the articular head and cavity. The articular head is represented by the navicular articular surface, facies articularis navicularis, and the anterior calcaneal articular surface, facies articularis calcanea anterior, which are located on the talus. The articular cavity is formed by the posterior articular surface, facies articularis posterior, of the navicular bone and the anterior talar articular surface, facies articularis talaris anterior, of the calcaneus. The articular capsule is attached to the edges of the articular surfaces.

Subtalar, talocalcaneal-navicular, calcaneocuboid, spheno-navicular, tarsal-metatarsal joints.

The plantar calcaneonavicular ligament, ligamentum calcaneonaviculare plantare, strengthens the joint capsule from below. In the place where the ligament is in contact with the head of the talus, in its thickness there is a layer of fibrous cartilage, which is involved in the formation of the articular cavity. When it is stretched, the head of the talus descends and the foot flattens. On the dorsal surface, the joint is strengthened by the talonavicular ligament, ligamentum talonavicular. This ligament connects the dorsal surface of the neck of the talus and the scaphoid. On the sides, the joint is strengthened by the lateral talocalcaneal ligament, ligamentum talocalcaneum laterale, and the medial talocalcaneal ligament, ligamentum talocalcaneum mediale. The lateral talocalcaneal ligament is located at the entrance to the sinus tarsi in the form of a wide ribbon, has an oblique direction of the fibers and goes from the lower and outer surfaces of the neck of the talus to the upper surface of the calcaneus. The medial talocalcaneal ligament is narrow, extending from the tuberculum posterius tali to the posterior edge of the sustentaculum tali of the calcaneus. The tarsal sinus, sinus tarsi, is filled with a very strong interosseous talocalcaneal ligament, ligamentum talocalcaneum interosseum.

Despite the fact that the talocalcaneonavicular joint is spherical in shape of the articular surfaces, movement in it occurs only around an axis that passes through the medial part of the head of the talus to the lateral surface of the calcaneus (slightly below and posterior to the place of attachment of the ligamentum calcaneofibulare). This axis also serves as an axis for the articulatio subtalaris. Consequently, both joints function as a combined talo-tarsal joint, articulatio talotarsalis. In this case, the talus remains motionless, and together with the calcaneus and navicular bones, the entire foot moves.

When the foot rotates outward, the medial edge of the foot (supinatio) rises and at the same time it is brought (adductio). When the foot rotates inward (pronatio), the medial edge of the foot falls, and the lateral edge rises. In this case, the foot is retracted.

Thus, during foot movements, extension (extensio, or flexio dorsalis) is combined with supination and adduction (supinatio, adductio); flexion of the foot (flexio plantaris) can be combined with both pronation and abduction (pronatio, abductio), and with supination and adduction (supinatio, adductio). In a child (especially in the first year of life), the foot is in a supinated position, so when walking, the child places the foot on its lateral edge.

The ankle joint (supratalar joint), subtalar and talocalcaneal-navicular joints (articulatio talotarsalis) can function independently. In the first, flexion and extension predominate, in the other two - supination and pronation. But this rarely happens, usually they function together, forming, as it were, one joint - the joint of the foot, articulatio pedis, in which the talus plays the role of a bone disk.

The heel-cube joint, articulatio calcaneocuboidea, is formed by the articular surfaces: facies articularis cuboidea calcanei and fades articularis posterior ossis cuboidei.

The articular surfaces are saddle-shaped. The articular capsule on the medial side is thick, strong and tightly stretched, on the lateral side it is thin and free. The capsule is reinforced with ligaments, which are especially developed on the plantar side. The strongest of them is the long plantar ligament, ligamentum plantare longum. This ligament starts from the lower roughness of the calcaneus and consists of several layers. Its deep bundles are attached to tuberositas ossis cuboidei; the superficial bundles are the longest, they are thrown over the sulcus tendineus t. peronei longi (turning the groove into a channel in which the t. peroneus longus is located) and attached to the bases of ossa metatarsalia II-V.

Deeper than the long plantar ligament is the plantar calcaneocuboid ligament, ligamentum calcaneocuboideum plantare, consisting of short fibers that lie directly on the joint capsule and connect sections of the plantar surfaces of the calcaneus and cuboid bones.

The calcaneocuboid joint is saddle-shaped in shape, but functions as a uniaxial rotational joint, combining with the talocalcaneonavicular and subtalar joints.

From a surgical point of view, articulatio calcaneocuboidea and articulatio talonavicularis (part of articulatio talocalcaneonaviculars) are considered as one joint - the transverse tarsal joint articulatio tarsi transversa (Chopard's joint). The articular surfaces of these joints have a slightly pronounced S-shaped shape, that is, they are located almost on the same transversely oriented line. Along this line, you can make an articulation of the foot. In this case, it is necessary to dissect a special bifurcated ligament, ligamentum bifurcatum (the key of Choparov's joint), which holds the calcaneus, scaphoid and cuboid bones relative to each other. Ligamentum bifurcatum (bifurcated ligament) begins on the upper edge of the calcaneus and is divided into two ligaments: calcaneonavicular, ligamentum calcaneonaviculare, and calcaneocuboid, ligamentum calcaneocuboideum. The calcaneonavicular ligament is attached to the posterolateral margin of the os naviculare, and the calcaneocuboid ligament is attached to the dorsal surface of the cuboid bone.

The wedge-shaped joint, articulatio cuneonavicularis, is formed by facies articularis anterior ossis navicularis and the posterior articular surfaces of ossa cuneiformia I-III, as well as the lateral articular areas of the sphenoid, cuboid and navicular bones facing each other. The joint cavity has the form of a frontal fissure, from which one process extends backward (between the scaphoid and cuboid bones), and three forward (between the three sphenoid bones and the cuboid). The joint is flat, the joint capsule is attached along the edges of the articular surfaces. The joint cavity is in constant communication with the articulatio tarsometatarsea II through the gap between the ossa cuneiformia mediale et intermedium. The joint is strengthened by the dorsal and plantar cuneiform ligaments, ligamenta cuneonavicularia plantaria et dorsalia, interosseous intersphenoid ligaments, ligamenta intercuneiformia interossea, dorsal and plantar intersphenoid ligaments, ligamenta intercuneiformia dorsalia etplantaria. Interosseous ligaments can only be seen on a horizontal cut of the foot or on an open joint when the articulating bones are pulled apart. The joint is typically flat, with little movement between the bones.

ANTI-METASATSA JOINTS. The joints between the tarsal and metatarsal bones (articulationes tarsometatarseae) are flat joints (only in articulation I of the metatarsal bone there are weakly pronounced saddle surfaces). There are three of these joints: the first is between os cuneiforme mediale and os metatarsale I; the second - between ossa cuneiformia intermedium et laterale and ossa metatarsalia II et III (the cavity of this joint communicates with the articulatio cuneonavicularis); the third is between os cuboideum and ossa metatarsalia IV et V.

All three joints from a surgical point of view are combined into one joint - the Lisfranc joint, which is also used to isolate the distal part of the foot. The joint capsules are strengthened by the dorsal and plantar tarsal-metatarsal ligaments, ligamenta tarsometatarsea dorsalia et plantaria.

Between the sphenoid and metatarsal bones there are also three interosseous sphenoid-metatarsal ligaments, ligamenta cuneometatarsea interossea. The medial interosseous sphenoid metatarsal ligament, which is stretched between the medial sphenoid bone and the second metatarsal bone, is the key of the Lisfranc joint. The tarsal-metatarsal joints are flat in shape, inactive.

Intermetatarsal joints, articulationes intermetatarseae, are formed by the surfaces of the metatarsal bones facing each other. Their capsules are strengthened by the dorsal and plantar metatarsal ligaments, ligamenta metatarsea dorsalia et plantaria. There are also interosseous metatarsal ligaments, ligamenta metatarsea interossea.

On the foot, as well as on the hand, one can distinguish a solid base, that is, a complex of bones that are connected to each other almost immobile (the movements here are minimal). The solid base of the foot contains more bones (10): os naviculare; ossa cuneiformia mediale, intermedium, laterale; os cuboideum; ossa metatarsalia I, II, III, IV, V, which is associated with the difference in the functions of the foot and hand.

The metatarsophalangeal joints, articulationes metatarsophalangeae, are formed by the heads of the metatarsal bones and the pits of the bases of the proximal phalanges. The articular surfaces of the heads of ossa metatarsalia II-V have an irregular spherical shape: the plantar section of the articular surface is significantly flattened. The articular pits of the phalanges are oval in shape. The joint capsule is free, attached at the edge of the articular cartilage; the back is very thin. From the lateral and medial sides, the joints are supported by collateral ligaments, ligamenta collateralia. On the plantar side, the joints are strengthened by plantar ligaments, ligamenta plantaria (these ligaments sometimes contain inclusions of fibrous cartilage and sesamoid bones). There is also a deep transverse metatarsal ligament, ligamentum metatarseum transversum profundum. It is a fibrous cord, which is located transversely between the heads of the I-V metatarsal bones and fuses with the capsules of the metatarsophalangeal joints, connecting the heads of all metatarsal bones. This ligament plays an important role in the formation of the transverse metatarsal arch of the foot.

Articulatio metatarsophalangea I differs in some features: two sesamoid bones are constantly enclosed in the plantar part of the capsule of this joint, which correspond to two grooves on the articular surface of the head of os metatarsale I. Therefore, the metatarsophalangeal joint of the thumb functions as a block joint. It performs flexion and extension around the frontal axis. The joints of the other four fingers function as ellipsoids. Flexion and extension around the frontal axis, abduction and adduction around the sagittal axis, and a small amount of circular motion are possible in them.

JOINTS OF FINGER BONES. The interphalangeal joints, articulationes interphalangeae, are similar in form and function to those of the hand. They belong to block joints. They are strengthened by collateral ligaments, ligamenta collateralia, and plantar ligaments, ligamenta plantaria. In the normal state, the proximal phalanges are in a state of dorsiflexion, and the middle ones are in plantar flexion.