The posterior muscle group of the leg. The superficial layer of the calf muscles (calf muscles) is triceps calf muscle (m. triceps surae), which forms the main mass of the calf elevation. It consists of two muscles - gastrocnemius muscle (m. gastrocnemius), located superficially, and soleus muscle (m. soleus) lying under it. Both muscles have one common tendon at the bottom.

Calf muscle (m. gastrocnemius) originates from the popliteal fossa fades poplitea of ​​the femur behind both condyles with two heads.

Both heads with their tendon origins (each of them has a synovial bag) fuse with the capsule of the knee joint and pass into the tendon, which, merging with the tendon m. soleus, continues into the massive Achilles tendon, tendo calcaneus (Achillis), attached to the posterior surface of the calcaneal tuber. At the point of attachment between the tendon and the bone, there is a synovial bag, bursa tendinis calcanei (Achillis).

soleus muscle (m. soleus) lies under the calf muscle. Thick and fleshy, it occupies a large extent on the bones of the lower leg. Its line of origin is located on both the head and on the upper third of the posterior surface of the fibula. Further, it descends almost to the border of the middle third of the lower leg from the lower one along the tibia.

Where the soleus muscle is thrown from the fibula to the tibia, there is a tendon arch, under which the popliteal artery and tibial nerve fit. Tendon stretching of the soleus muscle merges with the Achilles tendon.

Fig.1. The posterior muscle group of the leg. triceps calf muscle (m. triceps surae): calf muscle (m. gastrocnemius) and soleus muscle (m. soleus).

Notation

• m. - muscle - muscle
• n. - nervus - nerve
• a. - arteria - artery
• v. - vena - vein
• m. semitendinosus - semitendinosus muscle
• m. semimembranosus - Semimembranosus muscle
• m. gracilis - Thin muscle
• a., v. poplitea - Popliteal artery, popliteal vein
• m. sartorius - Tailor's muscle
• superior medialis genus - Medial superior genicular artery
• m.gastrocnemius, caput mediale - Medial head of the gastrocnemius muscle
• m.gastrocnemius, caput laterale - Lateral head of the gastrocnemius muscle
• ramus muscularis for m. soleus - Muscular branch of the tibial nerve for the soleus muscle
• m. soleus - soleus muscle
• v. saphena parva - Small saphenous vein of the leg
• m.gasstrocnemius - Calf muscle
• m. flexor digitorum longus - Long finger flexor
• m. tibialis posterior, tendo - Tibialis posterior, tendon
• a., v. tibialis posterior - Posterior tibial artery, vein
• malleolus medialis - medial malleolus
• m. flexor hallucis longus - flexor hallucis longus
• retinaculum musculorum flexorum - Tendon retinaculum of the flexor muscles
• ramus calcaneus a. tibialis posterioris - branch of the posterior tibial artery of the calcaneus
• tractus iliotibialis - ilio-tibial tract
• m. biceps femoris - biceps femoris
• n. tibialis - Tibial nerve
• n. peroneus (fibularis) communis - Common peroneal nerve
• superior lateralis genus - Superior lateral genicular artery
• m. plantaris, tendo - Plantar muscle, tendon
• tendo calcaneus - Achilles tendon
• m. gastrocnemius, caput laterale - lateral head of the gastrocnemius muscle
• n. cutaneus surae lateralis - Lateral cutaneous nerve of the calf (lat. Nervus cutaneus surae lateralis)
• n. cutaneus surae medialis - Medial cutaneous nerve / innervates the skin of the lower part of the back of the leg.
• m. peroneus (fibularis) longus, tendo - Long peroneal muscle, tendon
• m. peroneus (fibularis) brevis, tendo - Short peroneal muscle, tendon
• malleolus lateralis - Lateral malleolus
• retinaculum musculorum peroneorum (fibularum) superius - Superior tendon retinaculum of the peroneal muscles
• peronea (fibularis) - Peroneal artery
• rami calcanei by a. peronea (fibularis) - Calcaneal branches of the peroneal artery
• tuber calcanei - Calcaneal tubercle (back of the calcaneus)
• lig. collaterale fibulare - Peroneal collateral ligament
• m. biceps femoris, tendo - Biceps femoris, tendon
• interior lateralis genus - Inferior lateral genicular artery
• interior medialis genus - Inferior medial genicular artery
• caput fibulae - the head of the fibula
• m. peroneus (fibularis) longus - Long peroneal muscle
• m. peroneus (fibularis) brevis - Short peroneal muscle
• m. adductor magnus, tendo - Large adductor muscle, tendon
• lig. collaterale tibiale - Tibial collateral ligament
• m. semimembranosus, tendo - Semimembranosus muscle, tendon
• m. popliteus - Popliteal muscle
• arcus tendineus musculi solei - The tendinous arch of the soleus muscle

Like the muscles of the thigh and pelvic girdle, they are relatively strongly developed. Their auxiliary apparatuses are sufficiently developed, which is determined by their load in connection with upright posture, the musculoskeletal function of the lower limb. Having an extensive origin on the bones, intermuscular septa and fascia of the lower leg, the lower leg muscles act on the knee, ankle and foot joints.

There are anterior, posterior and lateral muscle groups of the lower leg. The muscles of the anterior group include the anterior tibial muscle, the long extensor of the fingers, the long extensor of the thumb; to the back - the triceps muscle of the leg (consisting of the gastrocnemius and soleus muscles), plantar muscle, popliteal muscle, long flexor of the fingers, long flexor of the big toe, posterior tibial muscle; to the lateral - long and short peroneal muscles.

Anterior leg muscles

Tibialis anterior located on the anterior surface of the lower leg, starts from the lateral condyle and the upper half of the lateral surface of the body of the tibia, the adjacent part of the interosseous membrane and from the fascia of the lower leg. At the level of the distal third of the lower leg, the muscle bundles pass into a long tendon, which successively passes under the upper and lower extensor retinaculums (tendons) anterior to the ankle joint, flexes the medial edge of the foot and attaches to the plantar surface of the medial sphenoid bone and to the base of the 1st metatarsal bone. The muscle unbends the foot in the ankle joint, simultaneously raises the medial edge of the foot and turns outward (supination), strengthens the longitudinal arch of the foot; with a fixed foot, tilts the lower leg forward; helps to keep the leg in a vertical position.

Long finger extensor- feathery muscle. It starts from the lateral condyle of the tibia, the anterior surface of the body of the fibula, from the upper third of the interosseous membrane, fascia and anterior intermuscular septum of the leg.

Heading to the rear of the foot, the muscle sequentially passes behind the upper and lower extensor retinaculums (tendons). At the level of the ankle joint, it is divided into four tendons, which are enclosed in a synovial sheath common to them. Each tendon is attached to the base of the middle and distal phalanges of fingers 2-5.

A small bundle is separated from the lower part of the muscle - the third peroneal muscle, the tendon of which is attached to the base of the 5th metatarsal bone. The muscle extends 2-5 fingers in the metatarsophalangeal joints, as well as the foot in the ankle joint. The third peroneal muscle raises the lateral edge of the foot. With a strengthened foot, similarly to the anterior tibial muscle, the long extensor of the fingers holds the lower leg in a vertical position.

Long extensor thumb foot is located between the anterior tibial muscle medially and the long extensor of the fingers laterally, partially covered by them in front. It starts from the middle third of the anterior surface of the fibula, the interosseous membrane of the leg. The tendon of the muscle passes down to the dorsum of the foot under the superior and inferior extensor retinaculums (tendons) in a separate synovial sheath and attaches to the distal phalanx of the big toe. Separate tendon bundles can also attach to the proximal phalanx. The muscle extends the big toe; also involved in the extension of the foot in the ankle joint.

Triceps muscle of the leg consists of two muscles - the gastrocnemius muscle, which is located superficially, and the soleus muscle, hidden under the gastrocnemius. The gastrocnemius muscle is a biarticular muscle, it passes through two joints - the knee and ankle, while the soleus muscle is single-joint - it passes only through the ankle joint.

Calf muscle has two heads) - medial and lateral, the surface layers of which are represented by strong tendon bundles. The lateral head begins on the outer surface of the lower epiphysis of the femur above the lateral condyle; medial head - on the medial condyle of the thigh. Under each of the heads of the gastrocnemius muscle is a synovial bag. Between the lateral head and the capsule of the knee joint, there is a lateral podshezhinous bag of the gastrocnemius muscle. Between the medial head and the joint capsule lies the medial gastrocnemius bursa. Both bags, as a rule, communicate with the cavity of the knee joint.

In the middle of the lower leg, both heads of the gastrocnemius muscle pass into a thick tendon, which tapers downward and merges with the tendon of the soleus muscle, forming the calcaneal (Achilles) tendon, which is attached to the calcaneal tuberosity. Between the tendon and the bone there is a synovial bag - a bag of the calcaneal tendon.

soleus muscle thick, flat, lying in front of the gastrocnemius muscle. In front of it are the muscles of the deep layer. The soleus muscle has an extensive origin on the posterior surface of the tibia and from the tendon arch that extends between the tibia and fibula. The muscle of the pennate structure passes into a flat tendon, which is involved in the formation of the calcaneal tendon. The triceps muscle of the lower leg flexes the lower leg and foot (plantar flexion); with a fixed foot, it holds the lower leg on the talus, preventing it from tipping forward.

plantar muscle inconsistent, with a small abdomen and a long thin tendon. It originates on the lateral epicondyle of the thigh and from the oblique popliteal ligament. The tendon of this muscle passes between the gastrocnemius and soleus muscles, is adjacent to the medial edge of the calcaneal tendon, with which it is attached to the calcaneal tuberosity. The muscle stretches the capsule of the knee joint, is involved in the flexion of the lower leg and foot.

Hamstring lies deep in the popliteal fossa. It begins with a thick tendon from the outer surface of the lateral condyle of the thigh (below the attachment of the peroneal collateral ligament). The muscle is adjacent to the posterior surface of the knee joint and passes under the arcuate popliteal ligament, from which its medial bundles begin. It is attached to a triangular platform on the posterior surface of the tibia, above the line of the soleus muscle. The muscle flexes the lower leg, turning it inwards; stretches the capsule of the knee joint, protecting the synovial membrane from infringement.

Long finger flexor- bifid muscle. It begins in fleshy bundles on the posterior surface of the body of the tibia below the line of the soleus muscle, from the fascia of the lower leg and from the posterior intermuscular septum of the lower leg. They are located behind and medial to the posterior tibial muscle.

The tendon of the long flexor of the fingers goes down, crosses the tendon of the posterior tibial muscle from behind and from the lateral side. Further, the tendon of the muscle passes to the sole of the foot behind the medial malleolus under the retinaculum (tendons) of the flexors in a separate synovial sheath (between the tendons of the posterior tibial muscle medially and the long flexor of the thumb laterally). Then the tendon goes around behind and below the support of the talus, located above the short flexor of the fingers, is divided into four separate tendons, which are attached to the distal phalanges of the 2nd to 5th fingers, having previously pierced the tendons of the short flexor of the fingers (similar to the tendons of the deep flexor of the fingers on the hand). The muscle flexes the distal phalanges of 2-5 fingers; flexes the foot, turning it outward.

flexor thumb longus feet - bipennate muscle. It starts from the lower two-thirds of the body of the fibula, the interosseous membrane, the posterior intermuscular septum of the leg. It is located laterally and behind the tibialis posterior muscle. The flexor hallucis longus tendon passes under the flexor retinaculum (tendons) behind the medial malleolus and lateral to the flexor hallucis longus tendon in a separate synovial sheath. Further, the tendon of the long flexor of the big toe lies in the groove of the same name on the posterior process of the talus, passing forward under the support of the talus. Upon reaching the plantar surface of the big toe, the tendon attaches to the distal phalanx of the big toe. On its way on the foot, this tendon crosses with the tendon of the long flexor of the fingers (lies under it). Throughout the plantar surface of the I metatarsal bone, the tendon of the long flexor of the big toe lies between the medial and lateral bellies of the short flexor of the big toe. The muscle flexes the big toe, is involved in flexion, supination and adduction of the foot; strengthens the longitudinal arch of the foot.

Tibialis posterior located deep on the back of the leg, between the long flexor of the fingers (medially) and the long flexor of the big toe (laterally). It starts on the posterior surface of the body of the fibula (between the medial crest and interosseous margin), from the lower surface of the lateral condyle and the upper two-thirds of the body of the tibia (below the line of the soleus muscle) and the interosseous membrane of the leg. The muscle continues into a strong tendon that lies in a groove on the posterior surface of the medial malleolus in front of the tendon of the long flexor of the fingers by the flexor tendon retinaculum. Moving to the plantar surface, the tendon is attached to the tuberosity of the navicular bone, to all three sphenoid bones, and also to the base of the 4th (sometimes 5th) metatarsal bone. The muscle flexes the foot (plantar flexion), adducts it, and supinates.

Lateral leg muscle group

The lateral group is represented by the long and short peroneal muscles, which are located on the lateral surface of the lower leg under the fascia plate, between the anterior and posterior intermuscular septa.

Peroneus longus muscle, two-pinnate, lies superficially. It starts from the head and the upper two-thirds of the lateral surface of the fibula, from the lateral condyle of the tibia, the fascia of the lower leg and from the intermuscular septa of the lower leg. At the level of the ankle joint, the tendon of the muscle, bending around the lateral ankle from behind, passes first under the upper retinaculum (tendons) of the peroneal muscles in the common synovial sheath with the tendon of the short peroneal muscle, and then in the groove on the calcaneus under the lower retinaculum (tendons) of the peroneal muscles. On the sole, the tendon of the long peroneal muscle runs obliquely forward and medially, lies in the groove of the same name in the cuboid bone in a separate (own) synovial sheath; attached to the base of the 1st and 2nd metatarsal bones and to the medial sphenoid bone.

At points where the tendon changes direction (behind the lateral malleolus and on the cuboid bone), it usually thickens due to the fibrocartilage or sesamoid bone that forms in its thickness. The muscle flexes the foot, raises its lateral edge (pronation), strengthens the transverse and longitudinal arches of the foot.

Peroneus brevis bipinnate, starts from the lower two-thirds of the lateral surface of the fibula and from the intermuscular septa of the lower leg. The tendon of the muscle passes to the foot behind the lateral malleolus, lying in the common synovial sheath together with the tendon of the long peroneal muscle under the retinaculum (tendons) of the peroneal muscles. At the lower edge of this retainer, the tendon of the short peroneal muscle turns forward and passes along the outer side of the calcaneus under the fibular block to the place of attachment at the base of the 5th metatarsal bone. The muscle raises the lateral edge of the foot; prevents the foot from turning with the sole inside; flexes the foot (plantar flexion).

The lower leg is part of the lower limb and is located between the knee and the foot. The lower leg is formed by two bones - the tibia and the fibula, which are surrounded by muscles on three sides that move the foot and fingers.

Lower leg bones

Tibia

The tibia at its upper end expands, forming the medial and lateral condyles. On the top of the condyles are the articular surfaces that serve for articulation with the condyles of the thigh; between them is the intercondylar eminence. Outside, on the lateral condyle there is an articular surface for articulation with the head of the fibula. The body of the tibia is like a trihedral prism, the base of which is turned backwards; it has three surfaces corresponding to the three sides of the prism: inner, outer and back. Between the inner and outer surfaces is a sharp leading edge. In its upper section, it passes into a well-defined tibial tuberosity, which serves to attach the tendon of the quadriceps femoris muscle. On the back surface of the bone is a rough line of the soleus muscle. The lower end of the tibia expands and on the inside has a protrusion directed downwards - the medial malleolus. On the distal epiphysis of the tibia is the lower articular surface, which serves for articulation with the talus.

Fibula

The fibula is long, thin and located laterally. At the upper end, it has a thickening, the head, which articulates with the tibia, at the lower end it also has a thickening, the lateral malleolus. Both the head and the malleolus of the fibula protrude outward and are easily palpable under the skin.

Joints of the bones of the lower leg

Between both bones of the lower leg - the tibia and fibula - is the interosseous membrane of the lower leg. The head of the fibula is articulated with the tibia by means of a joint that has a flat shape and is reinforced in front and behind by a ligamentous apparatus. The lower ends of the leg bones are connected by syndesmosis. The joints between the bones are inactive.

Leg muscles

On the lower leg, the muscles are located on three sides, making up the anterior, posterior and outer groups. The anterior muscle group extends the foot and fingers, and also supinates and adducts the foot. These include the tibialis anterior, extensor digitorum longus, and extensor hallucis longus. The posterior group of muscles that flexes the foot and fingers are: the triceps muscle of the lower leg, the long flexor of the fingers and the long flexor of the big toe, the posterior tibial muscle, the popliteal muscle. The outer group of muscles abducts, pronates and flexes the foot; it includes the long and short peroneal muscles.

Tibialis anterior

The tibialis anterior muscle originates from the outer surface of the tibia, the interosseous membrane, and the fascia of the leg. Going down, it passes under two ligaments located in the area of ​​the ankles and ankle joint - the upper and lower retainers of the extensor tendons, which are places of thickening of the fascia of the lower leg and foot. Attaches the anterior tibial muscle to the medial sphenoid bone and the base of the first metatarsal bone. This muscle is well felt under the skin throughout, especially in the transition area from the lower leg to the foot. Here, her tendon protrudes when the foot is extended. The function of the anterior tibial muscle is that it contributes not only to the extension of the foot, but also to its supination.

Long finger extensor

The extensor digitorum longus lies outside the tibialis anterior in the upper leg. It starts from the upper end of the tibia, the head and anterior edge of the fibula, as well as from the interosseous membrane and fascia of the leg. Passing to the foot, this muscle is divided into five tendons, of which four are attached to the distal phalanges of the second, third, fourth and fifth fingers, and the fifth - to the base of the fifth metatarsal bone.

The function of the long extensor of the fingers as a polyarticular muscle is not only to extend the fingers, but also to extend the foot. Due to the fact that one of the tendons of the muscle is attached to the outer edge of the foot, it not only unbends, but also somewhat penetrates the foot.

Long extensor thumb

The long extensor of the thumb starts from the inner surface of the fibula and the interosseous membrane in the region of the lower half of the leg. This muscle is weaker than the two previous ones, between which it is located. It is attached to the base of the distal phalanx of the thumb. The function of the muscle is that it is an extensor not only of the big toe, but of the entire foot, and also contributes to its supination.

Triceps muscle of the leg

The triceps muscle of the leg is located on the back of the leg and has three heads. Two of them make up the superficial part of this muscle and are called calf muscle, and the deep one forms the soleus muscle. All three heads pass into one common, calcaneal (Achilles) tendon, which is attached to the tuber of the calcaneus.

The place of origin of the gastrocnemius muscle is the medial and lateral condyles of the thigh. Its medial head is better developed and descends somewhat lower than the lateral one. The function of these heads is twofold: flexion of the lower leg at the knee joint and flexion of the foot at the ankle joint.

The soleus muscle originates from the posterior surface of the upper third of the body of the tibia, as well as from the tendon arch located between the tibia and fibula. This muscle is located deeper and somewhat lower than the calf muscle. Passing behind the ankle and subtalar joints, the soleus muscle causes flexion of the foot.

The triceps muscle of the lower leg is clearly visible under the skin and is easily palpable. The calcaneal tendon protrudes significantly posterior to the transverse axis of the ankle joint, due to which the triceps muscle of the leg has a large moment of rotation in relation to this axis.

The medial and lateral heads of the gastrocnemius muscle are involved in the formation of the popliteal fossa, which has the shape of a rhombus. Its boundaries are: above and outside - the biceps femoris, above and inside - the semimembranosus muscle, and below - two heads of the gastrocnemius muscle and plantar muscle. The bottom of the fossa is the femur and the capsule of the knee joint. Through the popliteal fossa pass the nerves and blood vessels that feed the lower leg and foot.

Long finger flexor

The long flexor of the fingers starts from the posterior surface of the tibia and passes to the foot under the medial malleolus in a special channel located under the ligament - the retainer of the flexor tendons. On the plantar surface of the foot, this muscle crosses the tendon of the long flexor of the thumb and, after attaching the square muscle of the sole to it, is divided into four tendons that are attached to the bases of the distal phalanges of the second to fifth fingers.

The function of the long toe flexor is to flex and supinate the foot and to flex the toes. It should be noted that the square muscle of the sole, attached to the tendon of this muscle, contributes to the "averaging" of its action. The fact is that the long flexor of the fingers, passing under the medial malleolus and fan-shaped dividing towards the phalanges of the fingers, causes not only their flexion, but also some reduction to the median plane of the body. Due to the fact that the square muscle of the sole pulls the tendon of the long flexor of the fingers outward, this adduction is somewhat reduced and the flexion of the fingers occurs to a greater extent in the sagittal plane.

flexor thumb longus

The long flexor of the thumb is the strongest muscle among all the deep muscles of the back of the leg. It starts from the lower part of the posterior surface of the fibula and the posterior intermuscular septum. On the plantar surface of the foot, this muscle is located between the heads of the short flexor of the thumb. It is attached to the plantar surface of the base of the distal phalanx of the thumb.

The function of the muscle is to flex the thumb and the entire foot. Due to the fact that the tendon of the muscle partially passes into the tendon of the long flexor of the fingers, it has some effect on the flexion of the second and third fingers. An increase in the moment of rotation of the long flexor of the thumb is facilitated by the presence of two large sesamoid bones on the plantar surface of the metatarsophalangeal joint of the thumb.

Tibialis posterior

The tibialis posterior muscle is located under the triceps muscle of the lower leg. It starts from the posterior surface of the interosseous membrane of the lower leg and adjacent areas of the tibia and fibula. Passing under the medial malleolus, this muscle attaches to the tuberosity of the navicular bone, to all the cuneiform bones and to the bases of the metatarsal bones. Its function is to flex the foot, adduct and supinate it.

Between the posterior tibial and soleus muscles is the shin-popliteal canal, which looks like a gap and serves to pass blood vessels and nerves.

Hamstring

The popliteal muscle is a short flat muscle directly adjacent to the back of the knee joint. It starts from the lateral condyle of the thigh, below the gastrocnemius muscle, and the bag of the knee joint, goes down and inward and attaches to the tibia above the line of the soleus muscle. The function of this muscle is that it contributes not only to flexion of the lower leg, but also to its pronation. Due to the fact that this muscle is partially attached to the capsule of the knee joint, it pulls it back as the lower leg flexes.

Peroneus longus muscle

The long peroneal muscle has a pinnate structure. It lies on the outer surface of the fibula, starts from its head, partly from the fascia of the leg, from the lateral condyle of the tibia and from the outer surface of the fibula in the region of its upper two thirds. In the lower third, the muscle covers the short peroneal muscle. The tendon of the long peroneal muscle wraps around the back and bottom of the lateral malleolus. In the region of the outer surface of the calcaneus, the muscle is held by ligaments - the upper and lower retainers of the tendons of the peroneal muscles. Passing to the plantar surface of the foot, the tendon of the muscle goes along the groove located on the lower surface of the cuboid bone, and reaches the inner edge of the foot. The peroneus longus attaches to the tuberosity on the undersurface of the base of the first metatarsal, to the medial cuneiform and to the base of the second metatarsal.

The function of the muscle is to flex, pronate, and abduct the foot.

Peroneus brevis

The short peroneal muscle originates from the outer surface of the fibula and the intermuscular septa of the lower leg. The tendon of the muscle bends around the lateral malleolus of the lower leg from below and behind and is attached to the tuberosity of the fifth metatarsal bone. The function of the short peroneal muscle is to flex, pronate, and abduct the foot.

The muscles of the lower leg are divided into anterior, lateral and posterior groups. The bones of the lower leg and the interosseous membrane separate the anterior and posterior muscle groups.

front group

1. Anterior tibial muscle (m. tibialis anterior; Fig. 85). Origin: lateral tibial condyle, interosseous membrane; attachment: plantar surface of the medial sphenoid bone, base of the 1st metatarsal bone.

Function: unbends and adducts the foot, simultaneously raising its medial edge.

2. Long extensor of the fingers (m. extensor digitorum longus; see Fig. 85). Origin: superior epiphysis of the tibia, head and anterior edge of the fibula, interosseous membrane; attachment: four tendons of the muscle end at the back of the II - IV fingers, while the middle bundle of each tendon is attached to the base of the middle phalanx, and two lateral ones - to the base of the distal phalanx. The fifth tendon attaches to the base of the fifth metatarsal.

Function: unbends II - IV fingers, unbends the foot, raising its lateral edge.

3. Long extensor hallucis longus (m. extensor hallucis longus; see Fig. 85). Beginning: the lower part of the medial surface of the body of the fibula, the interosseous membrane; insertion: base of distal phalanx, partially base of proximal phalanx.

Function: unbends the big toe and foot, raises the medial edge of the foot.

back group

Surface layer

1. The triceps muscle of the lower leg (m. triceps surae; Fig. 86) consists of the gastrocnemius and soleus muscles, which have a common tendon.

The gastrocnemius muscle (m. gastrocnemius) has two heads - lateral and medial. Beginning: heads begin on the corresponding epicondyles of a femur; attachment: common tendon to the calcaneal tuber.

Function: flexes the lower leg, flexes and rotates the foot outward.

The soleus muscle (m. soleus) is located under the gastrocnemius. Beginning: the head and upper part of the posterior surface of the body of the fibula, the line of the soleus muscle of the tibia; attachment: calcaneal tubercle, common tendon with gastrocnemius muscle.

Function: flexes the foot and rotates it outward.

2. The plantar muscle (m. plantaris; see Fig. 86) is rudimentary and unstable. Beginning: lateral condyle of a femur, bag of a knee joint; insertion: calcaneus.

Function: pulls back the capsule of the knee joint during flexion and rotation of the lower leg inward.

deep layer

1. Popliteal muscle (m. popliteus; see Fig. 86). Origin: lateral condyle of the femur, capsule of the knee joint; insertion: posterior surface of the body of the tibia.

Function: flexes the lower leg, rotates it inward, pulls back the capsule of the knee joint.

2. Long finger flexor (m. flexor digitorum longus; see Fig. 86). Beginning: an average third of a back surface of a body of a tibia; attachment: four tendons - on the sole to the base of the distal phalanges of II - V fingers.

Function: bends the distal phalanges of the II - V fingers and foot, rotating it outward.

3. Tibialis posterior muscle (m. tibialis posterior; see Fig. 86). Origin: interosseous membrane, posterior surfaces of the bodies of the tibia and fibula; attachment: tuberosity of the navicular bone, sphenoid bones of the foot.

Function: flexes the foot, rotates it outward and adducts.

4. Long flexor of the big toe (m. flexor hallucis longus; see Fig. 86.) Beginning: the lower two-thirds of the posterior surface of the body of the fibula, the interosseous membrane; insertion: base of the distal phalanx of the thumb.

Function: flexes the thumb, participates in the flexion of the foot and its outward rotation.

Lateral group

1. Long peroneal muscle (m. peroneus longus; see Fig. 85). Origin: head and upper body of the fibula; attachment: base of I - II metatarsal bones, medial sphenoid bone.

Function: flexes the foot, lowering its medial edge, abducts it.

2. The short peroneal muscle (m. peroneus brevis, see Fig. 85) is under the previous one. Beginning: the lower part of the lateral surface of the body of the fibula, the intermuscular septum; attachment: tuberosity of the V metatarsal bone.

Function: flexes the foot, raises its lateral edge, abducts the foot.

Anterior leg muscles
Anterior tibial muscle (m. tibialis anterior) (Fig. 197) is located on the anterior surface of the lower leg. It has a wide origin from the lateral upper third of the tibia, the fascia of the lower leg and the interosseous membrane. It passes near the anterior tibial crest under the retinaculum mm. extensorum superius et inferius in the fibrous canal and exits on the medial edge of the foot, where the tendon is attached to the plantar surface of the I sphenoid and metatarsal bones.

Function. Extends at the ankle joint and supinates the foot.

The long extensor of the first finger (m. extensor hallucis longus) (Fig. 197) is located lateral to m. tibialis anterior. It starts from the fibula and the interosseous membrane. It comes out between the anterior tibial muscle and the long extensor of the fingers. The tendon passes through the fibrous channel under the retinaculum mm. extensorum superius et inferius, ends at the base of the distal phalanx of the first finger.

Innervation: n. peroneus profundus (LIV-SI).

Function. Corresponds to the name of the muscle. In addition, the muscle is involved in the extension of the foot in the ankle joint.

197. Muscles of the lower leg and foot. 1 - tendo m. sartorius; 2 - tibia; 3 - m. gastrocnemius; 4 - m. soleus; 5 - m. tibialis anterior; 6 - tendo m. extensoris hallucis longi; 7 - tendo m. extensoris digitrum longi; 8 - retinaculum mm. extens6rum inferius; 9 - m. peroneus brevis; 10 - m. peroneus longus; 11-lig. patellae; 12 - tractus iliotibialis.

The long extensor of the fingers (m. extensor digitorum longus) is located lateral to m. tibialis anterior, covers the long extensor of the first finger. It starts from the upper third of the tibia, fibula, membrana interossea and fascia of the leg. The muscle is delimited from the anterior tibial muscle by the intermuscular septum. Forms a tendon that runs in the fibrous sheath under the retinaculum mm. extensorum inferius. Upon reaching the foot, the tendon is divided into 4 tendons, which are attached to the aponeurotic plate of the rear of the II-V fingers.

Innervation: n. peroneus profundus (LIV-SI).

Function. Unbends fingers II-IV, penetrates the outer edge of the foot together with the third peroneal muscle.

The third peroneal muscle (m. peroneus tertius) represents the fifth part of the long extensor of the fingers. This muscle is unstable (8.2%). It is attached to the fascia of the lateral part of the rear of the foot and to the fifth metatarsal bone.

The muscle is a derivative of the permanent muscle m existing in monkeys. peroneus parvus.

Innervation: n. peroneus profundus (LIV-SI).

Function. Unbends the foot at the ankle joint, raises the lateral edge of the foot.

198. Muscles of the lower leg and foot from the lateral side.

1 - m. extensor digitorum longus;
2 - m. extensor digitorum brevis;
3 - malleolus lateralis;
4 - m. peroneus brevis;
5 - m. peroneus longus;
6 - m. soleus;
7 - m. gastrocnemius;
8 - m. biceps femoris;
9 - tractus iliotibialis.

Lateral muscles of the leg
Long peroneal muscle (m. peroneus longus) (Fig. 198) occupies the lateral region of the lower leg, separated by an intermuscular septum from the long extensor of the fingers and m. soleus. It starts in two bundles from the head and body of the upper part of the fibula, the lateral tibial condyle and the fascia of the leg. The superficial peroneal nerve passes between the heads in the canalis musculoperoneus. The tendon arises above the lateral malleolus and passes under the retinaculum mm. peroneorum superius in the fibrous canal along with the tendon of the short peroneal muscle, bending around the lateral malleolus. Having reached the rear of the foot, the tendon penetrates the sole along the sulcus ossis cuboidei, where it reaches the medial edge of the foot, attaching to the I metatarsal and I cuneiform bones. On the sole, the tendon passes in the bone-fibrous canal.

Function. Flexes the foot at the ankle joint, raises the lateral edge of the foot.

The short peroneal muscle (m. peroneus brevis) lies under the previous one, shorter than it by a third. It starts from the fibula and intermuscular septa. The tendon of the muscle lies first in front of the long peroneal muscle, and then behind it, passes in the common fibrous canal, attaches to the tuberosity of the fifth metatarsal bone.

Innervation: n. peroneus superficial (LV-SI).

Function: Flexes and pronates the foot.

Back muscles of the leg
The triceps muscle of the leg (m. triceps surae) has three heads. The gastrocnemius muscle (m. gastrocnemius) starts from the areas above the lateral and medial condyles of the thigh with two heads, forming the lower border of the fossa poplitea, and also, together with the posterior wall of the articular capsule, limits the entrance to the canalis cruropopliteus; the soleus muscle (m. soleus) is covered by the gastrocnemius muscle. Starting from the linea poplitea tibiae, the head of the fibula and the tendon arch stretched between the bones of the lower leg, it connects below into a single powerful calcaneal tendon of the triceps muscle of the lower leg - tendo calcaneus (Achillis), attached to the calcaneal tubercle. Between the tendon and the calcaneal tuber there is a mucous bag.

Innervation: n. tibialis (LIV-SII).

Function. Flexes the foot at the ankle joint. When walking and running pushes the foot off the ground.

The plantar muscle (m. plantaris) starts from the area above the condyle of the thigh and the capsule of the knee joint. Then a thin tendon penetrates between the gastrocnemius and soleus muscles and is woven into the tendon of the triceps muscle of the lower leg.

Innervation and function. Same as the calf muscle.
The long flexor of the fingers (m. flexor digitorum longus) is located on the medial surface of the lower leg. It starts from the middle third of the posterior surface of the tibia and the deep fascia of the lower leg. The tendon reaches the medial malleolus and under the retinaculum mm. flexorum in the fibrous canal passes to the foot between the tendons m. tibialis posterior and m. flexor hallucis longus. On the foot it crosses with the tendon m. flexor hallucis longus, receiving from it a fibrous bundle of fibers. From the long flexor of the fingers also begins part of the muscle bundles m. quadratus plantae. Then the long flexor of the fingers is divided into four tendons, which, piercing the tendon of the short flexor of the fingers in the region of the phalanges, are attached to the base of the distal phalanges from II to V finger.

Innervation: n. tibialis (LV-SI).

Function. Bends the fingers, on which the foot rests when walking, and the foot at the ankle joint.

The tibialis posterior muscle (m. tibialis posterior) (Fig. 199) starts from the interosseous membrane and the bones of the lower leg of the entire posterior surface. The lower part is covered by the flexors of the fingers. The squamous tendon runs behind the medial malleolus and inserts on the tuberosity of the navicular and all of the cuneiform bones.

Function. Flexes at the ankle joint and supinates the foot, participates in maintaining its arches.

199. Muscles of the lower leg, rear view.
1 - m. gastrocnemius; 2 - m. soleus; 3 - m. tibialis posterior; 4 - m. flexor hallucis longus; 5 - m. peroneus longus; 6 - m. peroneus brevis; 7 - m. flexor digitorum longus; 8 - m. popliteus

The long flexor of the first finger (m. flexor hallucis longus) is a more massive muscle than the long flexor of the fingers and the posterior tibial muscle. It is located lateral to the previous muscles, bordering on the long and short peroneal muscles. It starts from the fibula and the intermuscular septum. Passes behind the medial malleolus and sustentaculum tali, surrounded by the synovial sheath in the fibrous canal. Attached to the distal phalanx of the first finger. Sesamoid bones are often found in the tendon.

Innervation: n. tibialis (LV-SII).

Function. Bends I finger, supports the inner arch of the foot. Due to the fibrous bundle that has entered the long flexor of the fingers, to some extent it helps to bend the other fingers.