A thick, flat, deep muscle in the posterior compartment of the lower leg. The tibialis posterior has extensive origins on the posterior, proximal surface of the tibia, fibula, and interosseus membrane. Its insertion is on the tarsal and metatarsal bones via a tendon that passes behind the medial malleolus and under the arch of the foot. Its primary actions are plantar flexion and inversion. It also helps to stabilize the longitudinal arch, especially during skating.
Subjects: Sports and Exercise Medicine.