Biomechanics of the Distal Interphalangeal Joint

This article summarizes the kinematics of the distal interphalangeal (DIP) joint during locomotion at walk and trot. The patterns and ranges of motion in flexion and extension are very similar at walk (range of motion: 46±40) and trot (range of motion: 47±40). In both gaits there is a cucle of flexion that peaks in the first half of stance. The joint is extended through the remainder of stance in opposition to a palmar moment generated by the deep digital flexor tendon and its accessory ligament and the navicular ligaments. During locomotion in a straight line, small amounts of abduction/adduction (∼50) and internal/external rotation (5-60) occur, especially around the times of contact and breakover. Extra-sagittal motions increase as a consequence of hoof imbalance, during turning or when the horse moves over uneven terrain.