Foot, ankle and lower leg

Foot, ankle and lower leg[edit | edit code]

The foot contains 26 bones that form numerous joints. The talus and calcaneus combine to form the subtalar joint. The calcaneus, cuboid and talus together with the navicular bone form the transverse joint of the forefoot. The five metatarsal bones, connecting at their bases with the tarsal bones (namely, the cuboid and sphenoid bones), form the tarsometatarsal joints, and the heads of the metatarsal bones, together with the phalanges of the fingers, form the metatarsophalangeal joints. The bones of each toe are connected by interphalangeal joints: on the big toe there is one joint, and on the rest there are two: proximal and distal. The joints of the foot are strengthened by many small ligaments.

Biomechanics of the ankle joint on x-ray

Medial

- close to the inside.

Hollow foot

- foot with a high longitudinal arch.

Flat foot

- foot with a low longitudinal arch.

Flat feet

- a disease characterized by flattening of the feet.

Own muscles of the foot

- muscles that begin and end within the foot.

Plantar aponeurosis

- a wide connective tissue plate on the sole, lying directly under the skin and stretching from the heel bone to the base of the toes.

Innervation

— providing organs, areas and parts of the body with communication with the central nervous system.

Lateral

- close to the outside.

There are two arches in the foot: longitudinal and transverse. The longitudinal arch runs along the medial (i.e., inner) edge of the foot, and the transverse arch runs across the foot, along a line connecting the heads of the metatarsals. A foot with too high a longitudinal arch is called hollow, and a foot with too low arches is called flat (and the disease itself is called flatfoot).

The intrinsic muscles of the foot are arranged in four layers and lie under the plantar aponeurosis, which supports the longitudinal arch of the foot. The foot muscles are innervated by the medial and lateral plantar nerves. These nerves travel between the metatarsal heads to the toes (interdigital nerves), where they are often injured in athletes.

The ankle joint is formed by the articulation of the distal end of the tibia and fibula with the talus. Foot movements occur simultaneously in the ankle joint, subtalar joint and transverse tarsal joint. The ankle joint is primarily responsible for dorsiflexion and plantar flexion of the foot; for pronation and supination of the foot - the subtalar joint (Fig. 2.1), and abduction and adduction of the foot occurs in the transverse tarsal joint.

Dorsiflexion

- movement of the foot upward (towards the rear).

Plantar flexion

- movement of the foot down (towards the sole).

Pronation

- rotation of the foot with the sole turning outward or the forearm with the palm turning down.

Supination

- rotation of the foot with the sole turning inward or the forearm with the palm turning upward.

Lead

- movement in the direction from the midline of the body.

Bringing

- movement towards the midline of the body.

Figure 2.1.

Range of motion in the ankle joint.
A.
Plantar and dorsiflexion.
B.
Supination and pronation.

Ankle joint

strengthened by several ligaments. On the lateral side, supination is limited by the anterior talofibular, calcaneofibular and posterior talofibular ligaments. The wide and large medial (deltoid) ligament, formed by fibers of four smaller ligaments, provides stability to the medial side of the ankle joint and prevents excessive pronation.

Extrinsic foot muscles

, providing movement of the toes and ankle joint, begin on the lower leg. The anterior muscle group (tibialis anterior, extensor hallucis longus, extensor digitorum longus, and peroneus 3) is responsible for dorsiflexion of the foot and extension of the toes. The lateral muscle group, consisting of the peroneus longus and brevis muscles, performs pronation of the foot. The deep muscles of the posterior calf group, particularly the tibialis posterior, flexor hallucis longus, and flexor digitorum longus, are responsible for supination of the foot and flexion of the toes. Plantar flexion of the foot is provided by the superficial muscles of the posterior group: gastrocnemius, soleus and plantar.

The gastrocnemius and soleus muscles are attached to the calcaneus by the Achilles (aka heel) tendon. The gastrocnemius and plantaris muscles originate above the knee joint, and the soleus muscle originates on the lower leg. This distinction will be important when discussing ankle exercises.

Around the ankle joint there are several supporting ligaments (retainers) that strengthen the tendons of the calf muscles where they cross the joint and transition to the foot. Extensor retinaculums are important for proper dressing application for anterior tibial syndrome.

Extrinsic foot muscles

- muscles starting on the lower leg and ending on the foot.

Origin of muscle

- the proximal point at which the muscle connects to the bone.

Retainer

- connective tissue formations that stabilize tendons or bones.

Palpable anatomical landmarks[edit | edit code]

Lateral surface

Anterior talofibular ligament
Calcaneofibular ligament
Posterior talofibular ligament

Medial surface

Medial ligament
Longitudinal arch of the foot

Front surface

Anterior tibiofibular ligament

Rear surface

Achilles tendon
Calf muscle
Soleus muscle

Plantar surface

Plantar aponeurosis
Transverse arch of the foot
Calcaneus

Back surface

First metatarsophalangeal joint

Anatomy of the foot

The anatomy of the foot and ankle is quite complex. The foot is made up of 33 bones, 26 joints and more than 100 tendons, muscles and ligaments. Together, these anatomical structures allow the weight of the body to be transferred in space.

The foot is required to be strong and stable to support the body in space when running, jumping, kicking and other movements.

Here is a brief description of the anatomy of the foot; you can read it in more detail in narrow sections.

Considering the bones of the foot, they can be divided into 3 groups: hindfoot, midfoot, forefoot.

Hindfoot: consists of the lower part of the tibia and fibula above and the talus below, forming the ankle joint, as well as the calcaneus, which with the talus forms the so-called subtalar joint.
Midfoot: The midfoot is formed by 5 bones, the navicular, which is cup-shaped and connects the talus to the three cuneiforms, and the cuboid, which connects the calcaneus to the 4th and 5th metatarsals.
The forefoot consists of 5 metatarsals, 19 phalanges and 2 sesamoid bones.

Thus, the bones of the foot form arches in the longitudinal and transverse directions. The bones of the foot are discussed in more detail in the section on bones of the foot, as well as in sections devoted to various diseases of the foot and ankle joint.

Another important part of the anatomy of the foot is the muscles. In total, there are more than 20 intrinsic muscles in the foot, which are often divided into 2 groups.

The first group is the own muscles of the foot. These are muscles that are completely located on the foot, on its plantar or dorsal surface.

The second group is formed by the muscles of the lower leg. These include the muscles located on the back of the lower leg, such as the gastrocnemius, soleus, tibialis posterior, and others. The extensor digitorum, thumb, and peroneal muscles are located along the anterior surface.

Different muscle groups work on the principle of antagonism. That is, the stability of the foot and ankle joint is achieved due to their simultaneous friendly work. The muscles of the foot are connected to the bones by tendons.

The most common problem affecting muscles and tendons is tendinitis, which is inflammation and degeneration of the tendons (where the tendon attaches to the bone). You can learn more about tendon diseases in the section of the site dedicated to diseases of the foot and ankle.

There are a huge number of ligaments of the foot; we will consider only the largest, thickest and most important for the function of support.

The ligaments of the foot are perhaps the most important and underestimated of all the anatomical structures of the foot. Only thanks to ligaments are bones held in their normal position and muscles can carry out movements. The ankle joint is stabilized by 11 major ligaments, the most commonly injured of which is the anterior talofibular ligament, which is responsible for the anterior-posterior stability of the ankle joint in a neutral position. The ankle joint ligaments are discussed in more detail in a separate article.

Tibialis anterior tendon problems

Tibialis anterior tendon ruptures are most often localized within 2-3 cm of its insertion point.

The cause of rupture may be tendon degeneration due to long-standing impingement caused by osteophytes of the talonavicular, scaphocuneiform, and metatarsocuneiform joints, or contact with the extensor retinaculum.

The tendon that is initially damaged most often undergoes ruptures, which is usually associated with a disruption of its blood supply.

Spontaneous rupture of the tibialis anterior tendon (arrows) most often occurs within the distal 3 cm of the tendon.

Ruptures most often occur in men aged 50-80 years, and their number increases with age.

Until the moment of rupture, the patient does not make any complaints.

Shortly before a rupture, patients may notice a small nodule appear in the area of tendon degeneration.

Tibialis anterior tendon tears usually occur as a result of sudden plantar flexion of the foot.

In younger, more physically active patients, an episode of trauma usually occurs, usually not severe, and the rupture is characterized by the appearance of acute pain in the corresponding area.

A patient with a rupture of the tibialis anterior tendon. A, In the plantar flexion position of the feet, no obvious signs of tendon rupture are visible. B, When the foot is dorsiflexed, there is no contour of the tibialis anterior tendon on the anterior surface of the right ankle joint.

A factor that provokes a rupture can be, for example, going down an inclined surface.

At the time of the rupture, the patient notices limited dorsiflexion of the foot, which most often forces him to seek medical help soon after the injury.

In older patients, the rupture occurs without trauma, and they often seek help only weeks or months after the rupture with complaints of foot drop.

Often these patients do not even remember what caused the rupture, and elderly patients do not even know that such a rupture occurred.

Patients often describe a clicking sensation followed by a brief episode of sharp pain in the anterior ankle followed by swelling in the area.

A rupture of the tibialis anterior tendon may be accompanied by the formation of a “tumor” on the anterior surface of the ankle joint.

In the first few hours after injury, patients may experience difficulty walking, but the pain decreases fairly quickly.

Patients may experience poor gait coordination, foot flopping, and an inability to walk without touching the toes. Over time, atrophy of the tibialis anterior muscle develops.

Base of stability or fulcrum (Features of the foot)

The human skeleton consists of 205 bones, 52 of which belong to the feet. Why so many? What functions does the foot perform? How is it structured? What are possible foot deformities? I will try to answer these and other questions in this article. The human foot is a unique creation of nature, it is difficult to say at what stage of evolution it was formed, but definitely among all living animals, no one has anything like it. In animals, the front and hind legs perform approximately the same function, either supporting or grasping. And therefore, they are similar in structure. In humans, the functions of the lower and upper extremities differ significantly.

Due to the need to completely free the upper limbs. Two diametrically opposed tasks fell upon our feet.

Firstly, it is necessary to provide stable support, that is, to be solid, durable, monolithic, for example, like a horse’s hoof.

Secondly, you need mobility, agility, and the ability to adapt to support. The way out of this contradiction was a unique vaulted structure in which different zones perform different functions.

Here is my favorite picture, I always show it to patients who complain of pain and deformation of the foot.

The main fulcrum points are A, B, C, the base of the 5th finger and the base of the 1st finger, respectively. Architectonics of the foot (the main structure of the foot) - arches AC, AB, and SV, arches of the feet, internal, external longitudinal and transverse arches.

So, a feature of the structure of our foot is the different functions of the internal longitudinal arch.

The outer longitudinal arch (cargo) and transverse arch mainly serve as a support. They are strengthened by ligaments, and normally flatten only under significant load, when we are carrying something heavy. Normally, these arches are preserved under body weight.

The internal, longitudinal (spring) arch is strengthened mainly by the short muscles of the foot and lower leg, this allows it to perform the function of shock absorption due to the flattening of the arch and rotation of the foot inward (pronation). On average, when walking on a hard surface, a person’s foot experiences an overload of approximately 18-20 g, while the shin accounts for only 6-7 g, that is, healthy feet absorb approximately 70% of the total impact load, the rest is absorbed by the cartilage of the joints and the spine, as a result, it does not reach the head more than 1g.

In addition to shock absorption, the inner arch and heel bone allow the foot to adapt to uneven footing and provide reliable grip on the surface, and most importantly, a smooth rolling gait.

It is precisely these differences in the structure of the arches of the foot that made it possible to combine two incompatible functions: stability and dynamics.

What other functions does the human foot perform? In addition to support, shock absorption and walking, the foot performs two other important tasks.

The first is the work of the so-called muscle pump. When the arch lowers, the muscles relax and the veins fill with blood; when the original state is restored, the muscles contract and squeeze blood out of the veins.

The second function is strangely sensitive, but the foot is a sensory organ. The skin of the foot contains a huge number of baroreceptors; these nerve endings respond to mechanical stimulation, which suggests that they play a leading role in maintaining balance and correct posture.

Nowadays, a huge number of methods for diagnosing feet have been invented, these are x-rays, computed tomography, pressography, sometimes they brought me an MRI of the feet, but the main method was and is the study of foot prints. The most common technique is podoscopy. The supporting areas of the feet are illuminated on the podoscope, and the brighter the light, the more pronounced the pressure on the support by this area of the foot.

What are the different types of foot deformities?

Figure 1 shows the imprint of a healthy foot, the heel imprint is shaped like a pear, the ratio of the support area in the middle part to the width of the foot is approximately ½, the arch of the transverse arch is clearly visible. In Figure 2 there is a hollow foot, a rare deformity accompanied by an increase in the height of the longitudinal arches. The heel print is a circle or oval; the midfoot is not in contact with the support. In Figure 3, hallux valgus is one of the most common foot deformities. In Figure 4, a flat foot is an increase in the area of support of the midfoot. In Figure 5 there is a flat-valgus foot, a combination of options 3 and 2.

With all possible deformations, the transverse arch can be preserved or flattened. It all starts in early childhood; from about 2 to 6-7 years old, the power frame of the foot is built and balanced. Ligaments and muscles are formed, the balance between different muscle groups is equalized. It is at this age that we can influence the formation of the foot and prevent the development of deformities.

Later, even in the absence of clinical manifestations, the program for subsequent foot deformities will have already been laid down, and it will be more difficult to influence changes in the structure.

Muscles , tendons and their sheaths, ligaments, fascia, aponeuroses, and capsules play an important role in ensuring joint stability. Pathology of periarticular soft tissues can be considered as conditions associated with arthritis, and as an independent pathology. When describing soft tissue pathology, the following concepts are usually used:

tendinitis – inflammation of tendon tissue;
tenosynovitis/tenosynovitis – inflammation of the tendon tissue and tendon sheath;
enthesitis/enthesopathy - inflammation of the tendon tissue at the site of its attachment to the bone;
Bursitis is an inflammation of the bursae, thin-walled cavities lined with synovium that facilitate the movement of tendons and muscles over bony prominences.

Pathology of the ankle joint and foot, as well as damage to the periarticular soft tissues of this area are a common reason for visiting a doctor, accounting, according to domestic and foreign literature, from 6 to 21% of all pathologies of the musculoskeletal system.

The causes of soft tissue pathology in the ankle and foot area can be both external and internal factors. External include overload (change in the stereotype of physical activity), trauma (single or repeated microtrauma), local injection of glucocorticosteroids (GCS) into the thickness of the tendon, which can cause degeneration of tendon tissue; internal include congenital anomalies of joint structures leading to disruption of biomechanics, muscle imbalance surrounding the joint, physical inactivity (immobilization), impaired blood supply to certain areas of the tendons, age-related involution of the musculoskeletal system. Often there is a combination of several factors.

Pain syndrome with damage to the soft tissues of the ankle and foot usually has a clear localization.

The main causes of pain in the heel area are:

Achilles tendinitis;
enthesitis of the Achilles tendon;
Achilles or retrocalcaneal bursitis;
subcalcaneal bursitis;
plantar fasciitis, heel spur.

And the hilly tendon is a continuation of the triceps surae muscle, which is formed from the gastrocnemius and soleus muscles. This rather powerful tendon attaches to the heel bone. Between the tendon itself and the bone, as well as between the tendon and the skin, there are synovial bursae.

The most common causes of chronic Achilles tendon pain are Achilles tendinitis, partial rupture, or bursitis. Typically, these diseases are manifested by the following symptoms:

mild, aching pain in the tendon area after running or physical activity, which gradually intensifies;
feeling of weakness in the leg;
episodes of diffuse or localized pain in the tendon area immediately or several hours after running;
swelling of the soft tissues in the tendon area;
a feeling of stiffness (“cloggedness”) in the muscle that goes away as the tendon “warms up” during exercise.

Achilles tendonitis

Tendinitis of the Achilles tendon (Achilles tendonitis) often occurs in seronegative spondyloarthritis, in patients with joint hypermobility syndrome, and with severe flat feet. With Achilles' pain, swelling and pain occur when there is a load in the area of the tendon or where the tendon attaches to the heel bone.

The main clinical symptoms characteristic of Achilles tendonitis:

pain in the heel, sometimes along the back of the shin;
flexing the foot increases pain;
the area of greatest pain is 2–3 cm above the junction of the tendon with the heel bone;
the tendon may be swollen and thickened.

Retrocalcaneal bursitis

Posterior calcaneal bursitis is clinically similar to Achilles tendinitis, but the pain often becomes excruciating and intensifies significantly with walking and prolonged standing, and swelling or swelling often appears above the site of attachment of the tendon to the heel bone. Ultrasound examination of this area helps differentiate the conditions.

Achilles tendon enthesopathy

The most common cause of development of Achilles tendon enthesitis is seronegative spondyloarthritis.

Enthesitis is often caused by trauma to the entheses or overload of the tendons . Enthesitis is manifested by pain during movement in which the corresponding muscle is involved. Pain occurs more clearly when the affected muscle is tense. Swelling of the surrounding tissues and tenderness in the area of the involved enthesis are determined. The outcome of enthesopathy is, as a rule, ossification of the enthesis with the development of enthesophytes.

Plantar fasciitis

Plantar fasciitis, the most common cause of heel pain, is inflammation of the insertion of the flexor digitorum brevis muscle on the tuberosity of the heel bone. Overstrain of these structures due to flat feet, degenerative diseases of the musculoskeletal system, seronegative spondyloarthritis leads to reactive inflammatory production of bone tissue or the formation of heel spurs secondary to stretching of these structures.

The main symptom of plantar fasciitis is pain along the entire plantar surface of the foot when walking. Usually this pain appears during the first steps after the patient gets out of bed in the morning, or after sitting for a long time.

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