Ulnotriquetral ligament

The ulnotriquetral (UT) ligament is an extrinsic palmar ulnocarpal ligament that connects the distal ulna to the triquetrum and forms an integral part of the triangular fibrocartilage complex (TFCC). It arises, together with the ulnolunate and ulnocapitate ligaments, from a common origin at the fovea of the ulna and the base of the ulnar styloid, and inserts onto the triquetrum. Rather than attaching directly to the ulna itself, the ulnocarpal ligaments largely attach to the palmar radioulnar ligament of the TFCC, an arrangement that permits greater independence between wrist and forearm motion.

Key anatomic and functional features:

• Components: The UT ligament has two components spanning both the palmar (volar) and dorsal cortices of the ulna and triquetrum; the volar UT ligament is the portion classically described as part of the TFCC.

• Origin/insertion: Proximally from the foveal region/base of the ulnar styloid; the ligament inserts on the palmar–radial aspect of the base of the ulnar styloid and blends with the volar margin of the TFCC distally as it reaches the triquetrum.

• Function: Along with the ulnolunate ligament, it acts as a stabilizer between the distal ulna and the ulnar carpus, contributing to dynamic wrist stability and load transmission; disruption can produce ulnar-sided wrist pain and instability.

• Clinical relevance: The dorsal UT ligament (DUTL) is implicated in "hockey wrist," where it is maximally strained in wrist flexion, pronation, and radial deviation and typically tears in a transverse midsubstance pattern proximal to its triquetral insertion.