Which muscle primarily dorsiflexes the ankle?

• A. Gastrocnemius
• B. Tibialis anterior
• C. Soleus
• D. Extensor digitorum longus

Answer: (B)

Dorsiflexion at the ankle is produced by muscles located on the front of the leg that pull the foot upward toward the shin. The main mover here is the tibialis anterior, the muscle running along the shin. It originates on the tibia and inserts on the medial cuneiform and first metatarsal, so when it contracts it lifts the front of the foot and slight inversion can occur as a secondary effect.

The other muscles listed don’t serve as the primary plantarflexors or dorsiflexors. Gastrocnemius and soleus lie at the back of the leg and drive plantarflexion (pointing the foot down). Extensor digitorum longus does extend the toes and can assist with dorsiflexion, but its primary role is toe extension rather than dominating ankle dorsiflexion.