Muscles of the Leg

Anterior Compartment Tibialis anterior muscle Extensor hallucis longus muscle Extensor digitorum longus muscle Fibularis (peroneus) tertius muscle All supplied by the deep fibular nerve

Tibialis anterior muscle

L4, L5 DF Inversion

Extensor Hallucis Longus muscle

L5, S1 Extends big toe Assists dorsiflexion of ankle Weak ankle inversion

Extensor Digitorum Longus muscle

L5, S1 Extends lateral four toes Ankle dorsiflexion Everts the foot at the subtalar joints

Fibularis tertius muscle Not seen in all people L5,s1 Ankle eversion at subtalar joint DF of foot at ankle joint

Lateral Compartment Muscles Fibularis longus muscle Fibularis brevis muscle Both innervated by the superficial fibular nerve, L5, S1, Both have actions of: Plantar flexion of ankle Eversion of ankle

Fibularis longus muscle Common fibular nerve Superficial fibular nerve

Fibularis brevis muscle

Posterior Leg Muscles Which nerve? Superficial posterior muscles Gastrocnemius muscle Soleus muscle Plantaris muscle Deep posterior muscles Popliteus muscle Flexor digitorum longus muscle Flexor hallucis longus muscle Tibialis posterior muscle

Gastrocnemius muscle

S1, S2 PF ankle Flexes leg at knee Inverts the foot at the subtalar joints

Soleus muscle

S1, S2 PF ankle Postural muscle Inverts the foot at the subtalar joints

Plantaris muscle

S1, S2 Weak PF Weak knee flexion Inverts the foot at the subtalar joints

Popliteus muscle

L4, L5, S1 Flexes knee Medially rotates the leg at the knee in open chain Laterally rotates the femur at the knee in closed chain

Flexor digitorum longus muscle

Assists inversion of the foot at the subtalar joints L5, S1, S2 Flexes lateral 4 toes Primarily distal phalanx PF ankle Assists inversion of the foot at the subtalar joints

Flexor hallucis longus muscle

L5, S1, S2 Flexes distal phalanx of big toe PF ankle Inversion of foot at subtalar joints

Note relationship of FDL and FHL

Tibialis posterior muscle

L4, L5 PF Inverts foot Supports arch of foot

Muscle Hints Tibialis *** muscles Fibularis *** muscle Common action: Common spinal level: Fibularis *** muscle

Superficial Post. Comp. muscles All Anterior and Lateral compartment muscles EXCEPT for Tibialis ant. muscle Common Spinal level: Superficial Post. Comp. muscles Common spinal level:

Toe flexor muscles Popliteus muscle Common spinal level Common actions: Popliteus muscle Spinal levels: