Ulnopisiform ligament

At a glance

English

Ulnopisiform ligament

Latin (TA2)

Ligamentum ulnopisiforme

System

Ligament

Region

Hand

Side

Single, on the midline

About the ulnopisiform ligament

The ulnopisiform ligament is the most medial and smallest of the bands grouped as the palmar ulnocarpal ligament. Its partners in the group are the ulnocapitate, ulnolunate and ulnotriquetral ligaments. It runs from the ulnar side of the soft-tissue complex around the head of the ulna towards the pisiform, the sesamoid bone on the front of the triquetrum.

It is a slender and variable band, and in many wrists it is hard to separate from the ulnotriquetral ligament and from the ulnar collateral ligament, which also sends a slip to the pisiform. Some descriptions treat it simply as the most medial fibres of the ulnocarpal group carried on to the pisiform. Its course lies close to the capsule of the joint between pisiform and triquetrum.

Its job is to add to the palmar support of the ulnar border of the carpus, tethering the pisiform and triquetrum to the forearm. The palmar ulnocarpal ligament as a whole ranks among the main stabilisers of the wrist joint, together with the dorsal and palmar radiocarpal ligaments, the dorsal ulnocarpal ligament and the two collateral ligaments.

Because the region is crowded, pain here can come from several sources: the disc complex at the end of the ulna, the pisotriquetral joint, the tendon of flexor carpi ulnaris, or the ulnar nerve and artery passing into the hand just beside the pisiform. Examination aims to tell these apart by pressing on each structure in turn.

Attachments and function

Attaches from

The ulnar side of the palmar ulnocarpal complex near the head of the ulna.

Attaches to

The pisiform, close to the capsule of the pisotriquetral joint.

Function

Adds palmar support to the ulnar edge of the carpus and helps tether the pisiform and triquetrum to the forearm.