The phylogeny of the wrist

The phylogeny, or evolutionary development, of the wrist can be traced from its origin as a pectoral fin of a fish living 400 million years ago. As species became more terrestrial, the wrist evolved into a weight-bearing joint, with syndesmotic attachment of the distal radius and ulna, the ulnar styloid articulating with the pisiform and triquetral bones. With the appearance of primates, the wrist took its present form, with no ulnocarpal articulation but with a synovially lined distal radioulnar joint and triangular fibrocartilage complex, allowing for wrist mobility.