ABSTRACT
Distal articulation • Smooth and trough-like, with a lip-like facet for the head of the ulna to lateral and rising to a pointed process on the medial side; human distal radius. • Button-like, with a raised process; human ulna head. • A dished, oval distal facet, with a small facet to lateral for the head of the ulna; dog, cat radius. • The distal end of the bone is blunt and rounded, and bears two rounded facets; dog, cat ulna. • The distal ends of the radius and ulna together make up a complex of intercon nected facets; two sinuous ridges cross the radius articulation obliquely, dividing it into two bulging medial areas and a lower lat eral/caudal area, to which a dished facet on the head of ulna is added when the two bones are held together or fused; bovids, cervids, pig. • The ridges on the distal articulation are very sharply developed; the area of the articulation as a whole is small relative to the size of the shaft; in mature animals the ulna is fused with the radius articulation to produce one continuous area; cervids. • Similar sharply developed ridges, the area of articulation is relatively larger than in cervids; in mature animals the fused ulna again forms one continuous area of articula tion with the radius; bovids. • Less sharply defined ridges; the radius articulation is deeper cranial-caudal, giving it a squarer distal outline; the ulna articulation is separate; pig. • The radius articulation is divided by a cranial-caudal ridge into two bulging areas; horse.
