Hand and Wrist Injuries: Part I. Nonemergent Evaluation Diagnosis of upper extremity injuries depends on knowledge of basic anatomy and biomechanics of the hand and wrist. The wrist is composed of two rows of carpal bones. Flexor and extensor tendons cross the wrist to allow function of the hand and digits. The ulnar, median, and radial nerves provide innervation of the hand and wrist. A systematic primary and secondary examination of the hand and wrist includes assessment of active and passive range of motion of the wrist and digits, and dynamic stability testing. The most commonly fractured bone of the wrist is the scaphoid, and the most common ligamentous instability involves the scaphoid and lunate. Whether a physician is working in a rural clinic or an urban academic center, or is attending a high school football game, acute injuries of the hand and wrist will be encountered. Patients may not appreciate the severity of these injuries and are as likely to pre...