[TA] the complex joint formed by the synovial joints between the talus and navicular bone medially and the calcaneus and navicular bones laterally that act as a unit in allowing the front of the foot to pivot relative to the back of the foot about the longitudinal axis of the foot, contributing to the total inversion and eversion movements. SYN: articulatio tarsi transversa [TA], Chopart joint, midtarsal joint, transverse tarsal articulation.