Triquetrum
Os triquetrum
Also known as: triquetral bone, triangular bone
A pyramid-shaped bone on the ulnar side of the proximal carpal row, carrying the pisiform on its palmar surface.
Overview
The triquetrum lies medial to the lunate. Its palmar surface bears an oval facet for the pisiform (pisotriquetral joint); its distal surface articulates with the hamate; its proximal surface contacts the articular disc of the TFCC (it touches the ulna only indirectly) during ulnar deviation. Its dorsal surface receives strong dorsal intercarpal and radiocarpal ligaments. It is the second most commonly fractured carpal bone, typically a dorsal cortical chip (avulsion) fracture from a fall on the outstretched hand or impingement of the ulnar styloid in hyperextension.
- Location
Medial (ulnar) side of the proximal carpal row.
Anatomy
- Articulations
Lunate, pisiform, hamate; articular disc of the TFCC.
- Ossification
Single centre ≈2–3 years.
Function
- Completes the proximal carpal row on the ulnar side
- Supports the pisiform
Clinical significance
Dorsal triquetral avulsion fracture
Second commonest carpal fracture; seen as a flake of bone dorsal to the carpus on the lateral wrist X-ray; usually treated conservatively.
Compiled from standard anatomy and physiology references — see the Skeletal System sources. For education only; not medical advice.