Which muscles invert the foot?

• A. Tibialis anterior and Tibialis posterior
• B. Peroneus longus and Peroneus brevis
• C. Gastrocnemius and Soleus
• D. Extensor digitorum longus and Extensor hallucis longus

Answer: (A)

Inversion of the foot means turning the sole inward, accomplished mainly by muscles that pull the medial side of the foot upward. The two primary invertors are the tibialis anterior and the tibialis posterior.

Tibialis anterior runs down the front of the leg and attaches to the medial aspect of the foot (medial cuneiform and the first metatarsal). When it contracts, it lifts the foot (dorsiflexion) and k's the sole toward the midline (inversion), helping control the foot during walking.

Tibialis posterior is in the deeper back of the leg and attaches to the navicular and other midfoot bones. Its contraction inverts the foot and also assists with plantarflexion, while supporting the medial arch of the foot.

The other muscles listed don’t invert the foot as their primary action. The peroneus longus and brevis are lateral-acting muscles that evert the foot. The gastrocnemius and soleus mainly plantarflex the ankle. The extensors of the toes are more about dorsiflexion and toe extension than inversion.