Lower Leg

Lower Leg

1. Anterior Compartment

   • Tibialis Anterior
     • N: L4, L5 (Deep Fibular N.)
     • A: Dorsiflexes ankle and inverts foot
   • Extensor Hallucis Longus
     • N: L4, L5 (Deep Fibular N.)
     • A: Extends great toe and dorsiflexes ankle
   • Extensor Digitorum Longus
     • N: L4, L5 (Deep Fibular N.)
     • A: Extends lateral four digits and dorsiflexes ankle
   • Peroneus Tertius
     • N: L4, L5 (Deep Fibular N.)
     • A: Dorsiflexes ankle and aids in eversion of foot

2. Posterior Compartment

   • Superficial
     • Gastrocnemius
       • N: S1, S2 (Tibial)
       • A: Plantar flexes ankle when knee is extended; raises heel during walking; flexes leg at knee joint
     • Soleus
       • N: S1, S2 (Tibial)
       • A: Plantar flexes ankle independent of position of knee; steadies leg on foot
     • Plantaris
       • N: L4, L5, S1 (Tibial)
       • A: Weakly assists gastrocnemius in plantar flexing ankle
   • Deep
     • Flexor Hallucis Longus
       • N: L5, S1, S2 (Tibial)
       • A: Flexes great toe at all joints; weakly plantar flexes ankle; supports medial longitudinal arch of foot
     • Flexor Digitorum Longus
       • N: L5, S1 (Tibial)
       • A: Flexes lateral four digits; plantar flexes ankle; supports longitudinal arches of foot
     • Tibialis Posterior
       • N: L5, S1, (Tibial)
       • A: Plantar flexes ankle; inverts foot
     • Popliteus
       • N: L4, L5, S1 (Tibial)
       • A: Weakly flexes knee and unlocks it by rotating femur 5° on fixed tibia; medially rotates tibia of unplanted limb

3. Lateral Compartment

   • Peroneus Longus
     • N: L5, S1, S2 (Superficial Fibular N.)
     • A: Everts foot and weakly plantar flexes ankle
   • Peroneus Brevis
     • N: L5, S1, S2 (Superficial Fibular N.)
     • A: Everts foot and weakly plantar flexes ankle