Wrist Joint – Anatomy, Nerve Supply, Functions

Blood Supply and Lymphatics of Wrist Joint

Blood supply to the forearm and hand arises from the ulnar and radial arteries. Both arteries provide vasculature to the wrist joint through penetrating branches from the dorsal and palmar carpal arches.[rx]

Lymphatic drainage occurs via lymphatic vessels that connect to the epitrochlear nodes and eventually the axillary nodes.[rx]

Nerves of Wrist Joint

The wrist joint receives innervation from the three major nerves of the forearm.[rx]

• Median nerve: Via the anterior interosseous branch
• Radial nerve: Via the posterior interosseous branch
• Ulnar nerve: Directly through its deep motor branches

Muscles of Wrist Joint

Muscles in the forearm control wrist movement. The body of each muscle is located proximally in the forearm, and their tendons extend distally across the wrist joint. Their actions can group muscles associated with the wrist joint.[rx]

• Flexion – Flexor carpi radialis, flexor carpi ulnaris, flexor digitorum superficialis, flexor digitorum profundus, and to a lesser extent flexor pollicis longus and palmaris longus
• Extension – Extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, extensor digitorum and to a lesser extent extensor indicis
• Abduction – Abductor pollicis longus, flexor carpi radialis, extensor carpi radialis longus, and extensor carpi radialis brevis
• Adduction – Flexor carpi ulnaris, extensor carpi ulnaris

Structure and Function of Wrist Joint

The function of the wrist joint is to provide a range of motion necessary to adequately perform daily functions while maintaining a physiologic level of inherent stability. This is accomplished, in part, by the osseous articular components creating a condyloid joint that permits simultaneous movement in two perpendicular planes, in this case, dorsopalmar and radioulnar.[rx] This movement allows for a wide range of motion necessary to facilitate the functional use of the hand.

The joint itself is formed through the articulations between the distal radius and the scaphoid, lunate, and triquetrum. The proximal articulation forms a concave shape composed of a combination of the distal end of the radius and articular disk. The distal articulation is convex and composed of the scaphoid, lunate, and triquetrum bones of the proximal hand. Note that the ulna is not part of the wrist joint itself, as it articulates with the distal via the distal radioulnar joint (DRUJ).[rx]

The four ligaments responsible for maintaining the stability of the joint are the palmar and dorsal radiocarpal ligaments and the ulnar and radial collateral ligaments.[rx] The palmar radiocarpal ligaments are the strongest supporting structures, and these ligaments connect the radius to both the proximal and distal rows of carpal bones. Besides stability, the ligaments also ensure that the hand and forearm move together during supination.

The dorsal radiocarpal ligament is similar to the palmar ligament except that it is located on the dorsal side of the wrist joint and its alternative function is to ensure that the hand moves with the forearm during pronation. The ulnar collateral ligament runs from the ulnar styloid process to the triquetrum and pisiform bones, and the radial collateral ligament runs from the radial styloid process to the scaphoid and trapezium bones. Both collateral ligaments provide stability by reducing lateral motion.

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