The tibialis anterior muscle is a long, narrow muscle in the anterior compartment of the lower leg. Arising from origins along the lateral condyle and proximal body of the tibia, it runs down the shin just lateral to the tibia. Just above the ankle, the muscular body of the tibialis anterior ends and its long tendon extends across the medial side of the ankle and into the foot. In the foot, the tendon forms insertions on the first metatarsal and first cuneiform bones.
The tibialis anterior functions as a dorsiflexor of the foot by pulling the top, or dorsum, of the foot towards the shin. Dorsiflexion results in the lifting of the toes off the ground, which is an important motion during walking and running to prevent tripping over one’s toes. The tibialis anterior also provides a slight inversion of the foot by pulling the plantar surface of the foot toward the body’s midline. This motion is important in balancing the body’s weight on the foot during locomotion or standing, and is especially important when standing on one foot.