Inversion describes a combined movement of the foot in which the sole is turned inwards. It is composed of supination of the rearfoot, adduction of the forefoot and slight plantar flexion.
Inversion takes place mainly in the lower ankle joint and the adjacent tarsal joints. Sudden, uncontrolled inversion under load can overstretch or strain the lateral ankle ligaments – the classic ankle sprain. Its counterpart is eversion.