Hand, Wrist, Forearm and Elbow

Key Anatomy

The wrist has eight carpal bones in two rows. From the thumb side, the proximal row is the scaphoid, lunate, triquetrum and pisiform, and the distal row is the trapezium, trapezoid, capitate and hamate, whose hook (hamulus) projects toward the palm. The scaphoid is the most often fractured carpal, usually from a fall on an outstretched hand, with tenderness in the anatomic snuffbox. Its blood supply enters distally, so a missed waist fracture can starve the proximal pole and cause avascular necrosis. At the elbow, the radial head articulates with the capitulum. On a lateral elbow a thin anterior fat pad is normal, but a visible posterior fat pad signals a joint effusion and possibly a hidden fracture.