The distal interphalangeal joints are saddle joints, formed by the distal trochlea of the medial phalanges and the articulating fossae of the distal phalanxes.
In dogs, the distal interphalangeal joints may present a small, spheroidal, sesamoid cartilage, located on the palmar side of the joint capsule. The joint capsule is thickened to form the collateral ligaments, which attach proximally to the shallow depressions on each side of the head of the middle phalanx and extend obliquely caudodistally to attach to the sides of the ungual crest of the distal phalanx. The dorsal ligaments are two elastic cords that extend across the dorsal part of the distal interphalangeal joint, attached proximally to the dorsal surface of the base of the middle phalanx and attached distally close together on the dorsal part of the ungual crest. They passively keep the claws retracted.