The shin is part lower limb and is located between the knee and 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 articular surface for articulation with the head of the fibula. Body tibia looks 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 rear surface bone is a rough line of the soleus muscle. The lower end of the tibia expands and 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
Long extensor fingers lies outward from the anterior tibial muscle in the upper part of the lower 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 capsule knee joint. Through the popliteal fossa pass the nerves and blood vessels that feed the lower leg and foot.
Long finger flexor
long flexor 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 most strong muscle among all deep muscles posterior surface 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 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.
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. Unbends in ankle joint and supinate 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.
Anatomy of the lower leg
Lower leg bones
The tibia has a fairly simple structure. This part of the leg consists of two bones of different sizes, which are called the tibia and fibula. The tibia connects to the femur at the knee joint and is the second largest bone in the human leg.
The tibia connects to the fibula below the knee joint.
The foot has a much more complex structure. It consists of more than twenty-six bones and thirty-three joints. The structure of the foot is in many ways similar to the structure of the hands, but the foot serves to carry much more weight. Therefore, her muscles and bones are stronger, but less mobile.
1 - Tibia; 2 - fibula; 3 - Bones of the foot
Leg muscles
The lower leg contains approximately 20 muscles. They are responsible for raising and lowering the leg, the movement of the toes. A sufficient number of muscles that move the legs start at the back of the knee and end at the foot.
The lower leg contains three groups of muscles: anterior (muscles responsible for the extension of the feet and fingers), external (peroneal muscle group responsible for the movement of the outer edge of the foot) and posterior (muscles responsible for the flexion of the feet and fingers).
The calf muscle is among the most powerful. It begins at the heel bone of the foot, attaching to it through the Achilles (calcaneal) tendon.
On the back of the lower leg are calves, consisting of two muscles: the calf ( big muscle, forming bulges visible under the skin) - it is formed by two parts or heads, due to which its rhomboid shape is achieved, and soleus - a type of flat muscle located under the gastrocnemius.
1 - Long peroneal muscle; 2 - Long extensor of the fingers; 3 - Short peroneal muscle; 4 - Tendon of the long extensor of the thumb; 5 - Tibia; 6 - Anterior tibial muscle; 7 - Upper retainer of the extensor tendons; 8 - Lower extensor tendon retinaculum
1 - Internal head of the gastrocnemius muscle; 2 - Calcaneal (Achilles) tendon; 3 - Plantar muscle; 4 - External head of the gastrocnemius muscle; 5 - soleus muscle
When a person walks, runs or jumps, calf muscle creates tension on the heel, and this helps to move forward.
The Achilles tendon is considered one of the most important parts of the lower leg. With the help of it, three muscles are attached to the calcaneus at once: plantar, calf and soleus.
The Achilles tendon enables a person to run, jump and engage in other types of physical activity.
Vessels and innervation of the leg
The lower leg is supplied with blood through the tibial arteries: posterior and anterior, which begin in the popliteal artery. The veins of the same name run along the corresponding arteries and terminate in the popliteal vein.
The innervation of the lower leg is due to the tibial and peroneal nerves.
Arteries and veins of the leg:
1 - Popliteal artery; 2 - Medial head of the gastrocnemius muscle; 3 - Tendon arch of the soleus muscle; 4 - Posterior tibial artery; 5 - Long finger flexor; 6 - Posterior tibial muscle; 7 - Deep peroneal nerve; 8 - Lateral head of the gastrocnemius muscle; 9 - soleus muscle; 10 - Tibial nerve; 11 - Peroneal artery; 12 - Long flexor of the big toe; 13 - Calcaneal (or Achilles) tendon
1 - Long peroneal muscle; 2 - Common peroneal nerve; 3 - Superficial peroneal nerve; 4 - Short peroneal muscle; 5 - Cutaneous branches of the superficial peroneal nerve; 6 - Calf nerve; 7 - Fascia of the lower leg; 8 - Anterior tibial vein; 9 - Anterior tibial muscle; 10 - Tibial artery; 11 - Deep peroneal nerve; 12 - Long extensor of the fingers; 13 - Long extensor of the big toe; 14 - The neurovascular bundle in the lower leg
1 - fibula; 2 - soleus muscle; 3 - Tibia; 4 - Tendon of the plantar muscle; 5 - Medial head of the gastrocnemius muscle; 6 - Small saphenous vein of the leg
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
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 on the back of the II - IV fingers, while middle beam each tendon is attached to the base of the middle phalanx, and two lateral - 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: head and top part 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). Start: middle third posterior surface of the body of the 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.
