ABSTRACT
The human hand has 27 bones divided into three groups: 8 carpal bones in the wrist, 5 metacarpal bones, and 14 phalanges of the £ngers. The carpal bones are arranged in two rows and have names reŸecting their shapes (see Figure 5.1). The bones of the distal row, from the lateral side to the medial side, include the trapezium (four sided with two parallel sides), the trapezoid (four sided), the capitate (the central bone), and the hamate (hook shaped). These four bones £t together, tightly bound by interosseous ligaments to form a relatively immobile unit that articulates with the metacarpals to form the carpometacarpal (CMC) joint. The bones of the proximal row include the scaphoid (boat shaped), the lunate (halfmoon shaped), the triquetrum (triangle shaped), and the pisiform (pea shaped). The proximal surfaces of the scaphoid, lunate, and triquetrum form a biconvex elliptical surface which articulates with the biconcave surface of the distal extremity of the radius. The articulation between the proximal and distal rows is called the midcarpal joint while articulations between adjacent bones are called intercarpal joints.
