Which muscle dorsiflexes and inverts the foot and inserts on the base of the first metatarsal?

• A. Tibialis Anterior
• B. Gastrocnemius
• C. Soleus
• D. Extensor Digitorum Longus

Answer: (A)

Focusing on which muscle can both dorsiflex the ankle and invert the foot, along with its insertion point, points to the tibialis anterior. Its tendon crosses the front of the ankle and attaches on the medial side of the foot at the base of the first metatarsal and the medial cuneiform. When it contracts, it pulls the foot upward (dorsiflexion) and toward the midline (inversion).

Gastrocnemius and soleus are mainly plantarflexors, attaching to the calcaneus, so they don’t produce dorsiflexion or inversion. Extensor digitorum longus does dorsiflex the foot and extends the toes, but its insertion is on the distal phalanges of the toes, not on the base of the first metatarsal, so it doesn’t invert in the same way.