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Table 9-10 Ligaments of the Wrist and Their Function Extrinsic Ligaments Function Palmar radiocarpal Volarly stabilizes radius to carpal bones; limits excessive wrist extension Dorsal radiocarpal Dorsally stabilizes radius to carpal bones; limits excessive wrist flexion Ulnar collateral Provides lateral stability of ulnar side of wrist between ulna and carpals Radial collateral Provides lateral stability of radial side of wrist between radius and carpals Ulnocarpal complex and articular Stabilizes and helps glide the ulnar side of wrist; stabilizes distal disk (or triangular fibrocartilage radioulnar joint complex) Intrinsic Ligaments Palmar midcarpal Forms and stabilizes the proximal and distal rows of carpal bones Dorsal midcarpal Forms and stabilizes the proximal and distal rows of carpal bones Interosseous Intervenes between each carpal bone contained within its proximal or distal row Accessory Ligament Transverse carpal Stabilizes carpal arch and contents of the carpal tunnel Adapted from Hertling, D., & Kessler, R. (2006). Management of common musculoskeletal disorders: Physical therapy principles and methods. Philadelphia, PA: Lippincott, Williams & Wilkins.; Oatis, C. A. (2004). Kinesiology: The mechanics and pathomechanics of human movement. Philadelphia, PA: Lippincott, Williams & Wilkins.; Weiss, S., & Falkenstein, N. (2005). Hand rehabilitation: A quick reference guide and review. St. Louis, MO: Mosby Elsevier.

The radial and ulnar collateral ligaments provide lateral and medial support, respectively, to the wrist joint. The ulnocarpal complex is more likely to be referred to as the triangular fibro- cartilage complex (TFCC) and includes the articular disk of the wrist. The TFCC is the major stabilizer of the distal radioulnar joint (DRUJ) and can tear after direct compressive force such as a fall on an outstretched hand. It is often seen in conjunction with a distal radius fracture. The cli- ent will complain of ulnar wrist pain with forearm rotation, ulnar deviation, and gripping (Weiss & Falkenstein, 2005). The articular disk is found at the distal end of the ulna where it articulates with the triquetrum and lunate. It functions as a shock absorber and spacer, filling the gap created between the ulna and the carpal bones. The gap occurs because the ulna does not extend as far distally as the radius (Lippert, 2000). The intrinsic ligaments of the wrist include the palmar and dorsal midcarpal ligaments and the interosseous ligaments. The palmar and dorsal midcarpal ligaments form and stabilize the proxi- mal and distal rows of the carpal bones. The interosseous ligaments stabilize the individual carpal bones to each other within their proximal or distal row. Like the extrinsic ligaments, the palmar midcarpal ligaments are stronger than the dorsal. The interosseous ligaments are considered the strongest in the wrist but are less rigid, which may allow larger loads of force to be sustained when falling on an outstretched arm. Despite the protective mechanical properties of the ligaments of the wrist, numerous sprains are reported (Oatis, 2004).