Re: Leg

Comments:
: : Leg I : : 1. Divide the leg into compartments and name the muscles, innervation, vasculature, and actions of each compartment. : : Anterior (dorsiflexion, extension of the toes, and some inversion): muscles: tibialis anterior (dorsiflexion, weak inversion, and flex the knee), extensor hallicus longus (dorsiflexion and extend the big toe), extensor digitorum longus (dorsiflexion and extend the lateral four digits). Innervation: deep peroneal nerve. Vasculature: anterior tibial artery and vein. : And peroneus tertius, I think, that can evert the foot. : : 5. What is the relationship of the peroneus tertius to the extensor digitorum longus? : : The peroneus tertius has the same relative origin as the extensor digitorum longus and travels through the extensor retinaculum with the tendons of the extensor digitorum longus, however the peroneus tertius tendon inserts on the distal phalange of the 5th metatarsal, deviating from the extensor digitorum longus. : I think peroneus tertius inserts on the proximal end, dorsal side, of the 5th metatarsal. Let me know if Gray's says differently, since I only have Hollinshead. : : 6. Discuss the insertions of the flexor tendons into the phalanges of the foot. : : The flexor hallicus longus inserts on the distal phalange of the 1st metatarsal and aids in extending the toe and helps to dorsiflex the foot. The flexor digitorum longus inserts on the bases of the distal phalanges of the lateral four digits. The tibialis anterior inserts on the plantar side of the foot on the medial cuneiform bone and the base of the distal phalanx of the great toe. The muscles all pass through the superior and inferior extensor retinaculum to reach their insertions. : The flexors pass through the flexor retinaculum, not the inferior and superior extensor retinacula. : Tibialis posterior instead of anterior? It would insert on the cuboid, cuneiform 2, and metatarsals 2+3, I think. : : 7. Discuss the insertions of the extensor tendons into the phalanges of the foot. : : The extensor digitorum longus inserts on the distal and middle phalanges of the lateral four digits and enters the foot via the flexor retinaculum. The tendons of the EDL and extensor hallicus long cross one another to reach their insertion points. The EHL courses obliquely across the plantar surface of the foot and inserts on the base of the distal phalanx of the big toe passing between the two sesamoid bones, which protect the tendon. The tibialis posterior inserts on the navicular bone with several other metatarsal connections on the plantar surface of the foot. : I think all the extensors come through the superior and inferior extensor retinacula, and that the tendons of the EDL and EHL don't cross (although FDL and FHL do). The tendons of the long extensors cross the dorsal surface of the foot and insert a single slip on the middle of the middle phalanges and two lateral slips on the bases of the phalanges, while the extensors brevis insert on the bases of the proximal phalanges to extend the metatarsal-phalangeal joints. Maybe Dr Evey can shed some light on their insertions. : I think you have the insertion of tibialis posterior right, but it's not an extensor. It plantar flexes and inverts the foot. Tibialis anterior passes through the extensor retinacula, but its only functions are dorsiflexion and inversion. : : : 10. What is the insertion of the peroneus longus? : : The peroneus longus inserts on the medial cuneiform bone and the base of the distal phalanx of the big toe. : Pretty sure this one doesn't go all the way to the distal phalanx - I think it stops at the proximal end of the first metatarsal. (Thereby supplying suspension support to the lateral longitudinal arch, tie beam support to the transverse arch, and staple support to the medial longitudinal arch) : : 15. Which muscles serve to invert the foot? : : The tibialis anterior, the tibialis posterior, and fibularis tertius. : I think tertius everts the foot, even though it's in the anterior compartment. It runs across the dorsum laterally to insert on the fifth metatarsal, and I don't think it could invert the foot from there.

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