Muscles of the Lower Leg Quiz

See Lateral Compartment. Option B is correct because the lateral compartment of the leg contains two muscles, fibularis longus and fibularis brevis, and their common function is eversion, turning the sole of the foot outwards. (They are also called peroneus longus and brevis; fibularis is now the preferred name.) Both muscles are supplied by the superficial fibular nerve, a branch of the common fibular nerve, and both have tendons that pass behind the lateral malleolus, the bony bump on the outer side of the ankle. Fibularis longus also assists plantarflexion and supports the arches of the foot, but eversion is what the compartment is known for. From the anatomical position only a few degrees of eversion are possible. In real life these muscles work to fix the inner edge of the foot during running and prevent it from inverting too much. Memory aid: each leg compartment has a signature action. Anterior lifts the foot (dorsiflexion), posterior pushes it down (plantarflexion), and lateral turns it out (eversion).

• Compartment: the lateral compartment of the leg.
• Muscles: fibularis longus and fibularis brevis.
• Action: eversion, turning the sole of the foot outwards.
• Nerve: the superficial fibular nerve supplies both.