The tibialis posterior, as the name indicates, originates from the back of the tibia. It also originates from the inside surface of the fibula (Lower leg bone) and the tissue between the two bony surfaces. It is a deep muscle, but towards the lower end emerges and passes in front of the flexor digitorum longus muscle and tapers into a tendon that inserts into six tarsal bones (navicular, three cuniforms, cuboid, and talus) and the bases of the second, third, and fourth metatarsals. This muscle flexes the foot and, working with the tibialis anterior, turns the sole of the foot inward. It is the strongest support for the arch of the foot.
