musculoskeletal system anatomy muscles of foot sheet done by: dina sawadha & mohammad abukabeer
Extensor retinaculum : A- superior extensor retinaculum (SER) : originates from the distal ends of the tibia and fibula ( just proximal to medial and lateral malleoli ) B- inferior extensor retinaculum (IER) : Y shaped ligament, originates from the lateral side of calcaneus and tarsal sinus, forms two bands ; superior band that passes to the medial malleolus and inferior band that passes to the navicular and medial cuneiform bone. - IER functions in the fixation of the tendons of the extensor muscles and peroneal nerve. - deep peroneal nerve and dorsalis pedis artery are deep to the extensor retinaculum ( both superior and inferior ). - a septum from the superficial part of IER separates the three compartments : 1- tibialis anterior ( 1st compartment ) 2- extensor hallucis longus ( 2nd compartment ) 3- extensor digitorum longus ( 3rd compartment ). - synovial sheath is a cover structure that resembles bursa but surrounds the entire tendon, and it has synovial membrane just like bursa and synovial cavities in joints.
Lateral ( peroneal ) retinaculum : - is a specialized retinaculum for peroneal muscles. A- superior peroneal retinaculum (SPR) :from lateral malleolus to the calcaneus, single band, peroneus brevis ( deep ) and peroneus longus ( superficial ) crosses the SPR side by side, so their tendons share the same synovial sheath. B- inferior peroneal retinaculum (IPR) : on lateral surface of the calcaneus, two bands, the tendons will move away from each other, so the synovial sheath will divide. Medial ( flexor ) retinaculum : - passes from anterior surface of the calcaneus to the medial malleolus then to the posterior surface of calcaneus. - structures that passes beneath the flexor retinaculum : ( I ) most anterior ------> ( V ) most posterior : I - synovial sheath of tibialis posterior II - synovial sheath of flexor digitorum longus III - posterior tibial artery IV - tibial nerve V - synovial sheath of flexor hallucis longus - the tibial artery is the site of anesthesia of the sole.
Dorsalis pedis artery : - it is a continuation of anterior tibial artery, superficial artery, deep to extensor retinaculum ( the first structure beneath the ER ). - note that the tendons run within the ER not beneath it, so the artery is deep to them and the ER but is superficial artery in the same time. - after being superficial it runs inferior to the 1st tendon of extensor digitorum brevis ( tendon of the hallucis belly ), then penetrates the 1st dorsal interosseous muscle and euns alongside with it, then at the plantar side joins the plantar arch. Muscles of the dorsum of foot : - two muscles, innervated by deep fibular nerve ( L5, S1 ) Muscles of the sole of foot : originate from calcaneus. A- 1st layer ( superficial ) : 1- abductor hallucis muscle ( for big toe ) 2- flexor digitorum brevis muscle "most superficial" ( for middle phalanges ) 3- abductor digiti minimi muscle ( for 5th phalanx ) - deep peroneal nerve is lateral to dorsalis pedis artery.
B- 2nd layer : 1- quadratus plantae muscle : originate from the calcaneus, inserts on the tendon of flexor digitorum longus ; flexor digitorum longus comes from the posterior compartment, changes its path from lateral to medial side to enter the sole, then inserts on the distal phalanges, it inserts on the tendon to change the axis of the tendon ( oblique ) to match the axis of the sole ( straight ). 2- lumbrical muscles : they are also connected to the tendon of the flexor digitorum longus ( originated from it ), they insert on the extensor expansion with four tendons. 3- tendons of flexor digitorum longus 4- tendon of flexor hallucis longus - tendons of all these muscles are on the same plane or level.
C- 3rd layer : 1- flexor hallucis brevis muscle : most medial, originate from the distal part of tarsal bones, inserts on the base of the proximal phalanx of big toe ( inferior border ) 2- adductor hallucis muscle : intermediate, originate from the distal part of tarsal bones, inserts on the base of the proximal phalanx of big toe ( lateral border ), two heads ; transverse ( between heads of lateral metatarsals ) and oblique ( from bases of metatarsals or cuneiforms ). 3- flexor digiti minimi brevis muscle : most lateral, originate from the distal part of tarsal bones, inserts on the inferior border of the base of 5th proximal phalanx. D- 4th layer : 1- planter interossei muscles : adductors, three muscles ; 1st muscle with 3rd toe, 2nd muscle with 4th toe, 3rd muscle with 5th toe. the big toe lacks interossei because it is the hallucis and has its own muscles, and the 2nd toe lack interossei because it is the axis ( in hand the 3rd finger is the axis ). 2- dorsal interossei muscles : abductors, four muscles ; 1st (on medial side) and 2nd (on lateral side) muscles with 2nd toe, 3rd muscle with 3rd toe, 4th muscle with 4th toe. the big toe and 5th toe lacks interossei because itthey have their own separate abductor muscles.
- Medial planter artery : Smaller, Deep to abductor hallucis muscle. - Lateral planter artery, Deep to the abductor hallucis muscle and flexor digitorum brevis muscle, Continue as planter arch, and Planter digital artery. - planter arteries and nerves ( medial and lateral ) are sandwiched between the 1st and 2nd layers. - planter arch is sandwiched between the 3rd and 4th layers. - tibial nerve branches in the sole companies the medial and lateral planters. - tendons of extensor digitorum muscle become superficial under extension stress and can be easily located. - dorsalis pedis artery is superficial to extensor hallucis and medial to the deep peroneal nerve. *actions and innervation of muscles are in the tables* thank you and good luck