11. Wrist radiograph, PA projection
Note the medial (ulnar) angulation of the articular surface of the distal end
of the radius (this surface articulates with the navicular [scaphoid] and lunate
bones in the radiocarpal joint). The four most proximal carpals — navicular
(scaphoid), lunate, triquetrum, and pisiform —
form a crescent-shaped array just distal to the distal end of the radius and
head of the ulna, with the roughly circular outline of the pisiform overlying
the triquetrum. The capitate and hamate occupy the concavity formed
by the distal aspect of the four proximal carpals. The trapezium and
trapezoid largely overlap each other and are interposed between the distal
pole of the navicular and the bases of the first and second metacarpals.
