The tibialis posterior (also tibialis posterior muscle, posterior tibial muscle, latin: musculus tibialis posterior) is a deep muscle of the posterior group of the lower leg. The tibialis posterior is situated the most centrally of all leg muscles and is the strongest among the muscles of the posterior compartment.
The tibialis posterior originates from the posterior surfaces of the tibia and fibula, it is also attached to the interosseous membrane of the leg.
The tibialis posterior inserts onto the navicular and medial cuneiform bones.
The main function of the tibialis posterior is flexion, adduction and supination of the foot. It also plays an important role in stabilizing the lower leg.
The tibialis posterior is innervated by the tibial nerve.