The anatomy and function of the contents of the human tarsal sinus and canal

Abstract

Abstract The ligaments of the tarsal sinus and canal, including the roots of the inferior extensor retinaculum, the cervical ligament and the ligament of the tarsal canal, have been restudied and their function has been correlated with the movements of inversion and eversion. The ligaments are extracapsular and their attachments are somewhat more complex than previously reported. A band of fibers, heretofore undescribed, has been designated as the “oblique talocalcaneal band.” It passes from the calcaneal attachment of the intermediate root of the inferior extensor retinaculum to join the talar attachment of the ligament of the tarsal canal. The ligament of the tarsal canal averages 5.6 mm in width and 1.6 mm in thickness compared with the cervical ligament which is 11.6 mm wide and 2.8 mm thick. The axis of talocalcaneal movement passes between the articular surfaces of the talocalcaneonavicular and subtalar joints and, as a consequence, these articulations move in directions opposite to one another in inversion and eversion. Direct observation during passive movement indicates that the cervical ligament limits inversion whereas the ligament of the tarsal canal plays little or no role in limiting either inversion or eversion. The ligament of the tarsal canal appears to maintain apposition of the talus and calcaneus in all positions.