Functional anatomy of the wrist.

The analysis of the carpal mechanism warrants detailed examination of the morphology of the wrist. Essentials of wrist morphology serve as a basis for the concept of the interdependent carpal articulation chains. In this concept the wrist joint functions with 3 parallel longitudinal chains. In each of these chains the proximal carpal functions as an intercalated bone. The specific shape of the intercalated bones establishes a simultaneous movement in the radiocarpal and the midcarpal joints which is a prerequisite as to their function. Intercarpal stability is obtained first of all by the linkage of the 3 chains to one another. In this connection, the contacts between the carpals and of the scaphoid and lunate to the radius play an important role. The scapholunate interosseous ligament is a most important factor in the mutual attuning of the positions of scaphoid and lunate. The ulnar articular chain functions with the articular disk as a support. Extensions of the articular disk insert into all bones of the ulnar articular chain. The function of some muscles as stabilizers of the wrist by virtue of the position of their tendons was confirmed by electromyographic observations.