THE JOINTS OF THE EVOLVING FOOT .2. THE INTRINSIC JOINTS

  • 1 January 1980
    • journal article
    • research article
    • Vol. 130  (JUN) , 833-857
Abstract
A description is given of the functional morphology of the intrinsic joints of the foot, with particular reference to the primates, and key human-derived features are defined. In the human subtalar joint the compromise axis has become reoriented into a very elevated position and more nearly in line with the functional foot axis than it is in subhuman primates. This provides for torque of the talus, and so the supported body weight, about the axis, during the stance phase of gait. In the subhuman primates the very oblique subtalar axis is important in inverting the foot into a grasping attitude. In subhuman primates the transverse tarsal joint complex plays an important role in supination of the forefoot, which complements inversion at the subtalar joint complex in achieving the ideal grasping position. This movement is rendered possible only by the helical action at the subtalar joint complex. In man the calcaneocuboid joint has been remodelled into a specialized sellar form which provides for an arcuate swing of the calcaneus upon the cuboid, with lateral movement of the heel, during the stance phase of gait; this brings the lamina pedis of the weight-bearing foot into close-packed position. Joints between the cuneiforms and the cuboids and the associated tarso-metatarsal joints show significant modifications in man.