Which muscles evert the foot?

• A. Tibialis posterior
• B. Fibularis (peroneus) longus and fibularis brevis
• C. Tibialis anterior
• D. Gastrocnemius

Answer: (B)

Eversion of the foot is produced mainly by the fibularis (peroneus) longus and fibularis (peroneus) brevis. These muscles lie on the lateral side of the leg, and when they contract they pull on the lateral edge of the foot, turning the sole outward at the subtalar and midfoot joints. The longus tendon travels under the foot to insert on the medial side (medial cuneiform and base of the first metatarsal), so its action combines eversion with some plantarflexion and helps support the transverse arch. The brevis attaches to the tuberosity of the fifth metatarsal, producing an outward turn of the sole with its pull.

In contrast, the tibialis posterior and tibialis anterior mainly invert the foot (and the former also plantarflexes, while the latter dorsiflexes). The gastrocnemius is a primary plantarflexor and does not serve as a major everter.