Detailed anatomy of the antebrachiocarpal joint in dogs.

A comparative study of the anatomy of the antebrachiocarpal (AC) articulation was carried out in 30 adult dogs with 60 joints. Although a considerable degree of similarity was found between the AC joint in dogs and the corresponding wrist joint in humans, a number of differences between these two homologous joints were also noted. The distal end of the ulna in dogs directly articulates with the ulnar carpal and accessory carpal bones forming a specialized antebrachiocarpal arrangement more adapted to running. The accessory carpal bone in dogs is a massive, long bone and is strikingly different from its homologue in humans, the pisiform bone. The joint between the accessory and ulnar carpal bones, which corresponds to the piso-triquetral joint in humans, is always connected with the AC joint, whereas in humans this communication could be found occasionally. The large radial carpal bone in dogs, characteristic for carnivores, corresponds to the fused scaphoid and lunate bones in humans, in whom this type of fusion is very rarely found. The palmar ulnocarpal and radiocarpal ligaments in dogs are distinctly intra-articular, whereas in humans these ligaments are intracapsular. One of the controversies of the AC joint in dogs is a structure located between the distal-most parts of the radius and ulna forming a strong bond between these two bones and a part of the antebrachial articular surface. It is cartilage-like and is composed of typical fibrocartilaginous tissue.(ABSTRACT TRUNCATED AT 250 WORDS)