Ankle/foot Extrinsic Muscles Flashcards
Gastrocnemius
O: medial epicondyle of femur; lateral epicondyle of femur
I: calcaneus via calcaneus (Achilles tendon)
A: NWB: ankle plantar flexion and knee flexion; WB: deceleration of internal rotation of lower limb, helps decelerate pronation, ankle plantar flexion during push-off
In: tibial nerve S1-2
Art: branches from the posterior tibial artery and popliteal artery
Soleus
O: upper fibula, soleal line of tibia
I: calcaneus via calcaneal (Achilles) tendon
A: NWB: plantar flexion; WB: decelerates the forward momentum of the tibia when the foot is on the ground
In: tibial nerve S1-2
Art: popliteal and posterior tibial artery
Plantaris
O: above lateral head of gastrocnemius on femur
I: calcaneus via calcaneal (Achilles) tendon
A: very weak knee flexor; NWB: weak ankle plantar flexion; WB: weak control of dorsiflexion
In: tibial nerve S1-2
Art: popliteal artery
Tibialis posterior
O: proximal posterior tibia, interosseous membrane, fibula
I: navicular, cuneiform, cuboid bones of bases of 2nd-4th MT
A: NWB: inversion, plantar flexion (medial malleolus serves pulley); WB: decelerates subtalar joint pronation, strong stabilizer of the midtarsal joint in the direction of supination
In: tibial nerve L5-S1
Art: anterior and posterior tibial artery
Flexor digitorum longus
O: lower 2/3 of tibia
I: bases of distal phalanges of lateral four toes
A: NWB: plantar flexion and inversion, flexes toes 2-5, supports longitudinal arch; WB: controls dorsiflexion, eversion and extension of toes
In: tibial nerve L5-S1
Art: posterior tibial artery
Flexor hallucis longus
O: inferior 2/3 of posterior fibula I: base of distal phalanx of 1st toe A: NWB: flexes 1st toe, weak plantar flexion; WB: controls extension of 1st toe, dorsiflexion In: tibial nerve L5-S2 Art: posterior tibial artery
Tibialis anterior
O: lateral tibia, proximal lateral surface of tibia, interosseous membrane
I: medial cuneiform, first metatarsal
A: NWB: inversion, dorsiflexion; WB: eccentrically controls plantar flexion at heel strike, helps control pronation of forefoot
In: deep peroneal nerve L4-S1
Art: anterior tibial artery
Extensor digitorum longus
O: lateral tibial condyle, fibula I: dorsal surface of phalanges 2-5 A: NWB: extension of toes 2-5, dorsiflexion; WB: controls flexion of toes, plantar flexion and inversion In: deep peroneal nerve L4-S2 Art: anterior tibial artery
Extensor hallucis longus
O: medial aspect of the fibula, interosseous membrane
I: distal phalanx of 1st toe
A: NWB: extends 1st toe, dorsiflexion, inversion; WB: control flexion of 1st toe, plantar flexion, and eversion
In: deep peroneal nerve L4-S1
Art: anterior tibial artery
Perineum (fibularis) tertius
O: distal 1/3 of anterior fibula; interosseous membrane
I: dorsal surface of base of 5th MT
A: NWB: dorsiflexion, eversion; WB: controls plantar flexion and eversion
In: deep peroneal nerve L4-S1
Art: anterior tibial artery
Peroneal (fibularis) longus
O: upper lateral fibula I: medial cuneiform, base of 1st MT A: NWB: eversion and abduction, weak plantar flexion; WB: stabilizes base of first ray, controls inversion, adduction and dorsiflexion In: superficial peroneal nerve L4-S1 Art: posterior tibial artery
Peroneus (fibularis) brevis
O: lower lateral 2/3 of fibula I: 5th metatarsal A: NWB: eversion and abduction, weak plantar flexion; WB: stabilizes 5th ray, controls inversion, adduction and dorsiflexion In: superficial peroneal nerve L4-S1 Art: posterior tibial artery
