Wrist

Figure 7-1. Normal radiographic anatomy of the wrist. A, PA view. Note the normal ulnar inclination of the distal radius (long white line). Also note
the approximately equal length of the distal ulna and radius (short transverse line) and the zigzag contour formed by the carpometacarpal joints. B, Diagram of the normal smooth carpal arcs. Interruption of one of these arcs is evidence of a ligamentous injury or carpal dislocation. C, Lateral view. The
long axes of the radius, capitate, scaphoid, and lunate are marked with lines. Note how the long axis of the scaphoid is estimated by connecting the two
most volar projections, which are relatively easy to identify. The radius, capitate, and lunate are approximately colinear. The scaphoid is angled approximately 45 degrees volar compared with the lunate. Note the volar tilt of the distal radial articular surface. Also note the normal fat pad volar to the
pronator quadratus muscle (arrowheads). c, Capitate; dr, distal radial articular surface; l, lunate; s, scaphoid.