Muscles of the Leg Anterior Compartment Tibialis anterior
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
• L 4, L 5 • DF • Inversion
Extensor Hallucis Longus muscle
• L 5, S 1 • Extends big toe • Assists dorsiflexion of ankle • Weak ankle inversion
Extensor Digitorum Longus muscle
• L 5, S 1 • Extends lateral four toes • Ankle dorsiflexion • Everts the foot at the subtalar joints
Fibularis tertius muscle • Not seen in all people • L 5, s 1 • 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, L 5, S 1, • 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
• S 1, S 2 • PF ankle • Flexes leg at knee • Inverts the foot at the subtalar joints
Soleus muscle
• S 1, S 2 • PF ankle • Postural muscle • Inverts the foot at the subtalar joints
Plantaris muscle
• S 1, S 2 • Weak PF • Weak knee flexion • Inverts the foot at the subtalar joints
Popliteus muscle
• L 4, L 5, S 1 • 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
• L 5, S 1, S 2 • Flexes lateral 4 toes – Primarily distal phalanx • PF ankle • Assists inversion of the foot at the subtalar joints
Flexor hallucis longus muscle
• L 5, S 1, S 2 • Flexes distal phalanx of big toe • PF ankle • Inversion of foot at subtalar joints
• Note relationship of FDL and FHL
Tibialis posterior muscle
• L 4, L 5 • PF • Inverts foot • Supports arch of foot
Muscle Hints • Tibialis *** muscles – Common action: – Common spinal level: • Fibularis *** muscle – Common action:
• All Anterior and Lateral compartment muscles EXCEPT for Tibialis ant. muscle – Common Spinal level: • Superficial Post. Comp. muscles – Common spinal level:
• Toe flexor muscles – Common spinal level – Common actions: • Popliteus muscle – Spinal levels:
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