The carpus in congenital anomalies of the hand.

Congenital anomalies of the carpus associated with congenital hand and upper limb anomalies were investigated from the point of view of the development of the hand. Defects of the carpus were categorized as follows: 1) Radial ray defect: loss of the scaphoid, trapezium and trapezoid. 2) Central ray defect: loss of the capitate and loss of a part of the trapezium and hamate. 3) Ulnar ray defect: loss of the triguetrum, pisiformis and hamate. Deficiencies of the carpus and more distal parts of the hand proved to be secondary to defects of the forearm bones in both the radial and ulnar ray. On the other hand deficiency of the carpus was secondary to defects of the phalanx and metacarpal of the middle finger in the central ray. Thus, from the standpoint of the development of the carpus, bipolar development of the bones of the hand originates proximally in both the radial and ulnar rays and distally in the central ray.