Muscles Acting on the Foot

muscle, origin, insertion, main action, and innervation.

Tibialis Anterior

• Origin: Lateral surface of tibia and adjacent interosseous membrane

• Insertion: Medial and inferior surfaces of medial cuneiform and adjacent surfaces on base of metatarsal 1

• Main Action: Dorsiflexion of foot at ankle joint; inversion of foot; dynamix support of medial arch of foot

• Innervation: Deep fibular nerve L4, L5

Gastrocnemius

Origin: Medial head—posterior surface of distal femur just superior to medial condyle, lateral head —upper posterolateral surface of lateral femoral condyle

Insertion: via calcaneal tendon to posterior surface of calcaneus

Main Action: Plantarflexes foot and flexes knee

Innervation: Tibial nerve S1, S2

Soleus

Origin: Soleal line and medial border of tibia; posterior aspect of fibular head and adjacent surfaces of neck and proximal shaft; tendinous arch between tibial and fibular attachments

Insertion: via calcaneal tendon to posterior surface of calcaneus

Main Action: Plantarflexes the foot

Innervation: Tibial nerve S1, S2

Fibularis Longus

Origin: Upper lateral surface of fibula, head of fibula, and occasionally the lateral tibial condyle

Insertion: Undersurface of lateral sides of distal end of medial cuneiform and base of metatarsal 1

Main Action: Eversion and plantarflexion of foot; supports mainly lateral and transverse arches of foot

Innervation: Superficial fibular nerve L5, S1, S2

Tibialis Posterior

Origin: posterior surfaces of interosseous membrane and adjacent regions of tibia and fibula

Insertion: mainly tuberosity of navicular and adjacent region of medial cuneiform

Main Action: inversion and plantarflexion of foot; support of medial arch of foot during walking

Innervation: Tibial Nerve L4, L5

Flexor hallucis longus

Origin: posterior surface of fibula and adjacent interosseous membrane

Insertion: plantar surface of distal phalanx of great toe

Main Action: Flexes great toe; particularly active during the toe-off phase of walking when the body is propelled forward off the stance leg and the great tow is the last part of the foot to leave the ground

Innervation: Tibial Nerve S2, S3

Flexor digitorum longus

Origin: medial side of posterior surface of the tibia

Insertion: plantar surfaces of bases of distal phalanges of the lateral four toes

Main Action: flexes lateral four toes

Innervation: Tibial Nerve S2, S3

Extensor digitorum longus

Origin: proximal ½ of medial surface of fibula and related surface of lateral tibial condyle

Insertion: via dorsal digital expansions into bases of distal and middle phalanges of lateral four toes

Main Action: Extension of lateral four toes and dorsiflexion of foot

Innervation: Deep fibular nerve L5, S1