tibialis

noun

tib·​i·​a·​lis ˌtib-ē-ˈā-ləs 

plural tibiales -(ˌ)lēz 

: either of two muscles of the calf of the leg:

a

: a muscle arising chiefly from the lateral condyle and part of the shaft of the tibia, inserting by a long tendon into the first cuneiform and first metatarsal bones, and acting to flex the foot dorsally and to invert it

called also tibialis anterior, tibialis anticus

b

: a deeply situated muscle that arises from the tibia and fibula, interosseous membrane, and intermuscular septa, that is inserted by a tendon passing under the medial malleolus into the navicular and first cuneiform bones, and that flexes the foot in the direction of the sole and tends to invert it

called also tibialis posterior, tibialis posticus