[TA] medial muscle of anterior (dorsiflexor) compartment of leg; origin, upper two thirds of lateral surface of tibia, interosseous membrane, and overlying crural fascia; insertion, medial cuneiform and base of first metatarsal; action, dorsiflexion and inversion of foot; provides dynamic support of longitudinal and transverse arches of foot; nerve supply, deep peroneal. SYN: musculus tibialis anterior [TA], anterior tibial muscle, musculus tibialis anticus.