1. COMPARTMENTS OF THE LEG The leg is divided into anterior, lateral and posterior fascial compartments separated by the tibial interosseous membrane and anterior and posterior inter muscular septa,which pass inwards from the investing deep fascia of the leg. The leg is divided into anterior, lateral and posterior fascial compartments separated by the tibial interosseous membrane and anterior and posterior inter muscular septa,which pass inwards from the investing deep fascia of the leg.

2. COMPARTMENTS OF THE LEG These fascial compartments are inextensible. These fascial compartments are inextensible. Any swelling within these compartments as a result of bleeding, infection or venous obstruction produces a rise in the intra compartmental pressure that will hinder its blood supply and produce tender,swollen muscles. Any swelling within these compartments as a result of bleeding, infection or venous obstruction produces a rise in the intra compartmental pressure that will hinder its blood supply and produce tender,swollen muscles.

3. CUTANEOUS NERVES (1) Antero- lateral surface of the leg (1) Antero- lateral surface of the leg A. The upper part A. The upper part Lateral cutaneous nerve of the calf. Lateral cutaneous nerve of the calf. B. The lower part B. The lower part Superficial peroneal nerve Superficial peroneal nerve

4. CUTANEOUS NERVES Both from Common Peroneal nerve Both from Common Peroneal nerve (2) Anteromedial surface of the leg : from Saphenous nerve (2) Anteromedial surface of the leg : from Saphenous nerve (from Femoral) nerve. (from Femoral) nerve.

5. MUSCLES 1. Tibialis Anterior. 1. Tibialis Anterior. 2. Extensor Digitorum longus. 2. Extensor Digitorum longus. 3. Extensor Hallucis longus. 3. Extensor Hallucis longus. 4. Peroneus Tertius. 4. Peroneus Tertius.

6. ORIGIN Only Tibialis Anterior is attached to the tibia. Only Tibialis Anterior is attached to the tibia. The others are attached to the fibula. The others are attached to the fibula. Only one extensor(peroneus tertius) is confined to the foot. Only one extensor(peroneus tertius) is confined to the foot.

7. TIBIALIS ANTERIOR Origin : Origin : upper ½ of lateral surface of tibia and interosseous membrane. upper ½ of lateral surface of tibia and interosseous membrane.

8. TIBIALIS ANTERIOR Insertion : Insertion : Medial cuneiform bone and the base of the adjacent (1 st ) metatarsal bone. Medial cuneiform bone and the base of the adjacent (1 st ) metatarsal bone. Action : Action : (1) Dorsiflexion of the foot. (1) Dorsiflexion of the foot. (2) Inversion of the foot. (3) Maintains the medial long. arch. (2) Inversion of the foot. (3) Maintains the medial long. arch.

9. EXTENSOR DIGITORUMLONGUS Origin : Origin : upper 2/3 of anterior surface of fibula and interosseous membrane. upper 2/3 of anterior surface of fibula and interosseous membrane.

10. Extensor Digitorum Longus Insertion Insertion The four tendons pass to the lateral four toes where they form the extensor expansion. The four tendons pass to the lateral four toes where they form the extensor expansion.

11. EXTENSOR EXPANSION The central part of the expansion is inserted to the bases of the middle phalanges of the lateral four toes. The central part of the expansion is inserted to the bases of the middle phalanges of the lateral four toes. The two lateral slips are inserted in the bases of the distal phalanges of the same toes. The two lateral slips are inserted in the bases of the distal phalanges of the same toes.

12. Extensor Digitorum Longus Action Action Extension of the lateral four toes. + weak Dorsiflexion. Extension of the lateral four toes. + weak Dorsiflexion. During walking these muscles pull the leg forward over the ground. During walking these muscles pull the leg forward over the ground.

13. EXTENSOR HALLUCIS LONGUS Origin : Origin : middle ½ of the anterior surface of the fibula and the interosseous membrane. middle ½ of the anterior surface of the fibula and the interosseous membrane.

14. Extensor Hallucis longus Insertion Insertion Base of the distal phalanx of the big toe. Base of the distal phalanx of the big toe. Action Action (1) Extension of the big toe. (1) Extension of the big toe. (2) Extension of the foot (Dorsiflexion). (2) Extension of the foot (Dorsiflexion). (3) Inversion of the foot. (3) Inversion of the foot.

15. PERONUS TERTIUS Origin : lower 1/3 of the anterior surface of the fibula and the interosseous membrane.

16. Peroneus Tertius Insertion Insertion Medial side of the dorsal surface of the 5 th metatarsal bone. Medial side of the dorsal surface of the 5 th metatarsal bone. Action: Action: (1) Extension of the foot. (1) Extension of the foot. 2) Eversion of the foot. 2) Eversion of the foot.

17. NERVE SUPPLY All the muscles are supplied by the Deep Peroneal (Anterior Tibial nerve). All the muscles are supplied by the Deep Peroneal (Anterior Tibial nerve).

18. ANTERIOR TIBIAL ARTERY Origin : Origin : It arises as a terminal branch of the popliteal artery at the lower border of popliteus. It arises as a terminal branch of the popliteal artery at the lower border of popliteus.

19. COURSE It passes forward above the interosseous membrane and it enters the anterior compartment through an opening in the upper part of the membrane. It passes forward above the interosseous membrane and it enters the anterior compartment through an opening in the upper part of the membrane. In company with the deep peroneal nerve. In company with the deep peroneal nerve.

20. COURSE In the upper part of its course it lies deep to the muscles while in the lower part it lies superficial in front of the lower end of the tibia. In the upper part of its course it lies deep to the muscles while in the lower part it lies superficial in front of the lower end of the tibia.

21. COURSE Here its pulsations can easily be felt. Here its pulsations can easily be felt. It has the tendon of the extensor hallucis longus on its medial side and the deep peroneal nerve and the tendons of extensor digitorum longus on its lateral side. It has the tendon of the extensor hallucis longus on its medial side and the deep peroneal nerve and the tendons of extensor digitorum longus on its lateral side.

22. TERMINATION In front of the ankle joint, it becomes the Dorsalis Pedis artery. In front of the ankle joint, it becomes the Dorsalis Pedis artery.

23. BRANCHES 1. Muscular. 1. Muscular. 2. Anastomotic : 2. Anastomotic : Malleolar around the ankle. Malleolar around the ankle. Recurrent around the knee. Recurrent around the knee.

24. DEEP PERONEAL NERVE (ANTERIOR TIBIAL NERVE) (ANTERIOR TIBIAL NERVE) Origin : Origin : It is one of the two terminal branches of the common peroneal nerve. It is one of the two terminal branches of the common peroneal nerve. It arises at the lateral side of the neck of the fibula in the substance of peroneus longus. It arises at the lateral side of the neck of the fibula in the substance of peroneus longus.

25. COURSE It passes around the neck of the fibula into the anterior compartment and descends in company with the anterior tibial vessels in front of the interosseous membrane. It passes around the neck of the fibula into the anterior compartment and descends in company with the anterior tibial vessels in front of the interosseous membrane.

26. COURSE Upper 1/3 : Upper 1/3 : It is lateral to the anterior tibial vessels. It is lateral to the anterior tibial vessels. Middle third Middle third It is superficial ( anterior ) to the anterior tibial vessels. It is superficial ( anterior ) to the anterior tibial vessels. Lower 1/3 Lower 1/3 It is lateral to the anterior tibial vessels. It is lateral to the anterior tibial vessels.

27. COURSE It passes under the extensor retinacula and enters the dorsum of the foot where it divides into terminal medial and lateral branches. It passes under the extensor retinacula and enters the dorsum of the foot where it divides into terminal medial and lateral branches.

28. TERMINAL BRANCHES Medial branch supplies the skin of the adjacent sides of the 1 st and 2 nd toes. Medial branch supplies the skin of the adjacent sides of the 1 st and 2 nd toes. Lateral branch supplies the extensor digitorum brevis. Lateral branch supplies the extensor digitorum brevis.

29. BRANCHES (1) Muscular to : (1) Muscular to : Dorsiflexors (anterior compartment of the leg). Dorsiflexors (anterior compartment of the leg). (2) Cutaneous : (2) Cutaneous : The skin in the web of the first toe. The skin in the web of the first toe. (3) Articular : (3) Articular : to the ankle joint. to the ankle joint.

30. DORSUM OF THE FOOT 1. Nerves: Cutaneous 1. Nerves: Cutaneous 2. Artery : Dorsalis Pedis 2. Artery : Dorsalis Pedis 3. Veins : Dorsal Venous arch. 3. Veins : Dorsal Venous arch. 4. Muscle : Extensor Digitorum Brevis 4. Muscle : Extensor Digitorum Brevis

31. CUTANEOUS NERVES (1) Saphenous nerve (1) Saphenous nerve It passes in front of the medial malleolus. It passes in front of the medial malleolus. It supplies the skin along the medial side of the foot as far as the head of the 1 st metatarsal bone. It supplies the skin along the medial side of the foot as far as the head of the 1 st metatarsal bone.

32. CUTANEOUS NERVES (2) SUPERFICIAL PERONEAL (2) SUPERFICIAL PERONEAL It supplies: It supplies: 1. The dorsum of the foot. 1. The dorsum of the foot. 2. The medial side of the big toe. 2. The medial side of the big toe. 3.The adjacent sides of the 2 nd,3 rd,4 th,5 th toes. 3.The adjacent sides of the 2 nd,3 rd,4 th,5 th toes.

33. CUTANEOUS NERVES (3) DEEP PERONEAL (3) DEEP PERONEAL It supplies: It supplies: Adjacent sides of the first and second toes. Adjacent sides of the first and second toes. (6) SURAL nerve (6) SURAL nerve It supplies: It supplies: lateral side of the foot and little toe. lateral side of the foot and little toe.

34. CUTANEOUS NERVES The nail beds and the skin over the dorsal surfaces of the terminal phalanges is supplied by the Medial and Lateral plantar nerves. The nail beds and the skin over the dorsal surfaces of the terminal phalanges is supplied by the Medial and Lateral plantar nerves.

35. DORSALIS PEDIS ARTERY It is the major source of arterial supply to the foot. It is the major source of arterial supply to the foot. Course : Course : It begins mid way between the malleoli and runs deep to the inferior retinaculum between the extensor hallucis longus and the extensor digitorum longus on the dorsum of the foot. It begins mid way between the malleoli and runs deep to the inferior retinaculum between the extensor hallucis longus and the extensor digitorum longus on the dorsum of the foot.

36. COURSE It is crossed by the inferior extensor retinaculum and the 1 st tendon of extensor digitorum brevis. It is crossed by the inferior extensor retinaculum and the 1 st tendon of extensor digitorum brevis. Lateral to it : terminal part of deep peroneal nerve and tendon of extensor digitorum longus. Lateral to it : terminal part of deep peroneal nerve and tendon of extensor digitorum longus. Medial to it : tendon of extensor hallucis longus. Medial to it : tendon of extensor hallucis longus.

37. PULSE The pulse of dorsalis pedis artery is easily felt as it passes between the tendons of extensor hallucis longus and The pulse of dorsalis pedis artery is easily felt as it passes between the tendons of extensor hallucis longus and extensor digitorum longus, midway between the medial and lateral malleoli. extensor digitorum longus, midway between the medial and lateral malleoli. (the foot is slightly dorsiflexed) (the foot is slightly dorsiflexed)

38. PULSE A diminished or absent pulse usually suggests vascular insufficiency resulting from arterial disease. A diminished or absent pulse usually suggests vascular insufficiency resulting from arterial disease.

39. BRANCHES 1. Lateral tarsal. 1. Lateral tarsal. 2. Arcuate : 2. Arcuate : It runs under the extensor tendons to the bases of the metatarsal bones. It gives metatarsal branches. It runs under the extensor tendons to the bases of the metatarsal bones. It gives metatarsal branches. 3. 1 ST dorsal metatarsal. 3. 1 ST dorsal metatarsal.

40. TERMINAL BRANCHES It passes to the 1 st interosseous space where it divides into : It passes to the 1 st interosseous space where it divides into : A. Deep plantar artery It passes to the sole of the foot where it joins the lateral plantar artery and completes the plantar arch. A. Deep plantar artery It passes to the sole of the foot where it joins the lateral plantar artery and completes the plantar arch. B. 1 st dorsal metatarsal artery. B. 1 st dorsal metatarsal artery.

41. DORSAL VENOUS ARCH It lies in the subcutaneous tissue over the heads of the metatarsal bones. It lies in the subcutaneous tissue over the heads of the metatarsal bones. It drains on the medial side into the Great Saphenous vein. It drains on the medial side into the Great Saphenous vein. On the lateral side to the Small Saphenous vein. On the lateral side to the Small Saphenous vein.

42. EXTENSOR DIGITORUM BREVIS Origin : Origin : from the anterior surface of the calcaneum and the inferior retinaculum. from the anterior surface of the calcaneum and the inferior retinaculum. It is divided into four tendons to the medial four toes. It is divided into four tendons to the medial four toes. The most medial one is the (Extensor Hallucis Brevis). The most medial one is the (Extensor Hallucis Brevis).

43. EXTENSOR DIGITORUM BREVIS Insertion : Insertion : Extensor hallucis brevis to the base of the proximal phalanx of the big toe. Extensor hallucis brevis to the base of the proximal phalanx of the big toe. The other three pass to the 2 nd,3 rd and 4 th toes with the other extensor tendons (of the extensor expansion). The other three pass to the 2 nd,3 rd and 4 th toes with the other extensor tendons (of the extensor expansion).

44. EXTENSOR DIGITORUM BREVIS Nerve supply : Nerve supply : deep peroneal nerve. deep peroneal nerve. Action : Action : It extends the 2 nd, 3 rd and 4 th toes at the inter phalangeal and metatarso - phalangeal joints. It extends the 2 nd, 3 rd and 4 th toes at the inter phalangeal and metatarso - phalangeal joints.

45. LATERAL COMPARTMENT (1) Peroneal muscles : Longus & Brevis. They are important in maintaining balance during standing. (1) Peroneal muscles : Longus & Brevis. They are important in maintaining balance during standing. (2) Nerves : Superficial Peroneal nerve. (2) Nerves : Superficial Peroneal nerve. (3) Arteries : Peroneal artery. (3) Arteries : Peroneal artery.

46. ORIGIN Peroneus Longus : upper 2/3 of the lateral surface of the fibula. Peroneus Brevis : lower 2/3 of the lateral surface of the fibula.

47. INSERTION Peroneus Longus : Base of the 1 st metatarsal bone. Medial cuneiform bone. It passes in a groove under the cuboid bone. Peroneus Brevis : The tendon passes behind and directly in contact with the lateral malleolus to be inserted to Tuberosity of the base of the 5 th metatarsal bone.

48. ACTION Peroneus Longus : (1) Plantar flexion of the foot (2) Eversion of the foot. (2) Eversion of the foot. (3) Holding up the lateral longtudinal arch. (4) A tie to the transverse arch.

49. ACTION Peroneus Brevis : (1) Plantar flexion of the foot. (2) Eversion of the foot. (3) Holding up the lateral longitudinal arch. Forced inversion (twisted ankles) often result in avulsion of the base of the 5 th metatarsal.

50. NERVE SUPPLY Superficial Peroneal (Musculo- cutaneouss nerve). Superficial Peroneal (Musculo- cutaneouss nerve).

51. SUPERFICIAL PERONEAL NERVE Origin : Origin : It is one of the terminal branches of the common peroneal nerve. It is one of the terminal branches of the common peroneal nerve. It arises in the substance of peroneus longus lateral to the neck of the fibula. It arises in the substance of peroneus longus lateral to the neck of the fibula.

52. COURSE It descends between peroneus longus and brevis muscles. In the lower part of the leg it emerges through the deep fascia and divides into medial and lateral branches. In the lower part of the leg it emerges through the deep fascia and divides into medial and lateral branches.

53. BRANCHES (1) Muscular to: peroneus longus and brevis. (1) Muscular to: peroneus longus and brevis.

54. BRANCHES (2) Cutaneous to: (2) Cutaneous to: A. The lower part of the front of the leg. A. The lower part of the front of the leg. B. The dorsum of the foot. B. The dorsum of the foot. C. The skin of the dorsal surface of all the toes C. The skin of the dorsal surface of all the toes

55. BRANCHES Except : Except : 1. The adjacent sides of the first and second toes. 1. The adjacent sides of the first and second toes. 2. The lateral side of the little toe. 2. The lateral side of the little toe.

56. PERONEAL ARTERY Origin : Origin : From the posterior tibial artery in the posterior compartment. From the posterior tibial artery in the posterior compartment. Branches : Branches : perforating branches to the Inferior part of the lateral compartment. perforating branches to the Inferior part of the lateral compartment.

57. SUPERIOR PART The muscles are supplied by perforating branches from the anterior tibial artery. The muscles are supplied by perforating branches from the anterior tibial artery.