Muscular System Appendicular (Lower Leg)

What is this muscle?

Gastrocnemius

What is the origin of Gastrocnemius?

Lateral head - Lateral condyle and posterior surface of femur above medial condyle

Medial head - Popliteal surface of femur above medial condyle

What is the insertion of Gastrocnemius?

Posterior surface of the calcaneus

What is the action of Gastrocnemius?

Plantar flexes foot, flexes leg at knee

What is this muscle?

Soleus

What is the origin of Soleus?

Posterior surface of the tibia (soleal line), upper third of posterior surface of fibula, fibrous arch between tibia and fibula

What is the insertion of Soleus?

Posterior surface of the calcaneus

What is the action of Soleus?

Plantar flexes foot

What is this muscle?

Tibialis Posterior

What is the origin of Tibialis Posterior?

Lateral part of posterior surface of tibia, interosseous membrane, proximal half of posterior surface of fibula

What is the insertion of Tibialis Posterior?

Tuberosity of navicular bone, cuboid, cuneiforms; second, third, and fourth metatarsals, sustentaculum tail of calcaneus

What is the action of Tibialis Posterior?

Plantar flexes, inverts foot

What is this muscle?

Tibialis Anterior

What is the origin of Tibialis Anterior?

Lateral condyle of tibia, upper half of lateral surface of tibia, interosseous membrane

What is the insertion of Tibialis Anterior?

Medial side and plantar surface of medial cuneiform bone, and base of first metatarsal bone

What is the action of Tibialis Anterior?

Dorsiflexes foot at ankle joint, inverts (supinates) foot

What is this muscle?

Flexor Digitorum Longus

What is the origin of Flexor Digitorum Longus?

Medial part of posterior surface of tibia

What is the insertion of Flexor Digitorum Longus?

Bases of distal phalanges of second, third, fourth, and fifth toes

What is the action of Flexor Digitorum Longus?

Flexes distal phalanges of lateral four toes, assists in plantar flexing foot, inverts foot

What is this muscle?

Flexor Hallucis Longus

What is the origin of Flexor Hallucis Longus?

Lower two-thirds of posterior surface of shaft of fibula, posterior intermuscular septum, interosseous membrane

What is the insertion of Flexor Hallucis Longus?

Base of distal phalanx of great toe

What is the action of Flexor Hallucis Longus

Flexes distal phalanx of great toe, assists in plantar flexing foot, inverts foot

What is the muscle?

Extensor Digitorum Longus

What is the origin of Extensor Digitorum Longus

Upper two-thirds of anterior surface of fibula, interosseous membrane, lateral condyle of tibia

What is the insertion of Extensor Digitorum Longus?

Along dorsal surface of four lateral toes, and then to bases of middle and distal phalanges

What is the action of Extensor Digitorum Longus?

Extends toes, dorsiflexes foot at ankle, everts foot

What is this muscle?

Extensor Hallucis Longus

What is the origin of Extensor Hallucis Longus?

Middle half of anterior surface of fibula and interosseous membrane

What is the insertion of Extensor Hallucis Longus?

Base of distal phalanx of great toe

What is the action of Extensor Hallucis Longus

Extends great toe, inverts foot

What is this muscle?

Peroneus Brevis

What is the origin of Peroneus Brevis?

Lower two-thirds of the lateral surface of the fibular shaft, plus the adjacent anterior and posterior intermuscular septa

What is the insertion of Peroneus Brevis?

Lateral side of the base of the fifth metatarsal bone (tuberosity/styloid process)

What is the action of Peroneus Brevis?

Everts the foot and assists with plantarflexion of the ankle, provides lateral stability to the ankle joint

What is this muscle?

Peroneus Longus

What is the origin of Peroneus Longus?

Upper outside part of the lower leg bone (fibula) and surrounding tissue

What is the insertion of Peroneus Longus?

Attaches to the medial cuneiform and the base of the first metatarsal on the inner side of the foot

What is the action of Peroneus Longus?

Eversion of the foot outward at the subtalar joint, Plantarflexion

What is this muscle?

Peroneus Tertius

What is the origin of Peroneus Tertius?

Lower third of anterior surface of fibula and interosseous membrane

What is the insertion of Peroneus Tertius

Dorsal surface of base of fifth metatarsal bone

What is the action of Peroneus Tertius?

Dorsiflexes and everts foot