Dorsal ulnocarpal ligament

At a glance

English

Dorsal ulnocarpal ligament

Latin (TA2)

Ligamentum ulnocarpeum dorsale

System

Ligament

Region

Hand

Side

Paired, left and right

About the dorsal ulnocarpal ligament

The dorsal ulnocarpal ligament reinforces the back of the wrist on its ulnar, or little-finger, side. It is one of the group of ligaments that hold the hand onto the forearm at the radiocarpal joint, alongside the dorsal radiocarpal ligament on the back, the palmar radiocarpal and palmar ulnocarpal ligaments on the front, and the ulnar and radial collateral ligaments at the sides.

A feature of the wrist explains its position. The ulna does not touch the carpal bones directly. Its lower end is separated from the lunate and triquetrum by a triangular fibrocartilage, the articular disc, which is attached to the edge of the radius and to the base of the ulnar styloid process. The dorsal ulnocarpal fibres run from the back of this disc and the adjoining ulnar region down to the backs of the triquetrum and lunate, blending with the joint capsule and with the dorsal radiocarpal ligament on their radial side. Close by, on the back of the ulna, runs the tendon of extensor carpi ulnaris in its own groove and sheath.

These fibres are generally thinner and less distinct than the palmar ulnocarpal ligaments. With the disc, the capsule and the extensor carpi ulnaris sheath, they form part of the soft-tissue complex on the ulnar side of the wrist that cushions load passing from the hand to the ulna and stabilises the distal radioulnar joint during turning of the forearm. They help limit excessive flexion and stop the carpus sagging away from the ulna.

Pain on the ulnar side of the wrist after a fall or after repeated twisting, as in racquet sports, is often due to injury of this soft-tissue complex. The articular disc is the part most often torn, but the dorsal capsular fibres may be involved too.

Attachments and function

Attaches from

The back of the articular disc of the distal radioulnar joint and the adjoining dorsal part of the lower ulna.

Attaches to

The dorsal surfaces of the triquetrum and lunate.

Function

Reinforces the back of the ulnar side of the wrist, helps limit excessive flexion and contributes to the stability of the ulnar side of the carpus.

Nerve supply

Articular branches of the posterior interosseous nerve and the dorsal branch of the ulnar nerve.

Blood supply

Branches of the dorsal carpal arch and the dorsal carpal branch of the ulnar artery.