Triquetrum

The triquetrum is the three-sided (pyramidal) carpal bone on the little-finger side of the wrist's near row. It meets the hamate and lunate, and carries the pea-shaped pisiform on its front surface. A pad of cartilage separates it from the ulna, so it does not meet the forearm bones directly.

Key facts

The triquetrum is named for its three-cornered shape.
It sits on the ulnar (little-finger) side of the wrist.
The pisiform bone sits in a facet on its front surface.
It does not touch the ulna — a cartilage disc fills the gap.
Small chip fractures of its back surface are common in wrist sprains.

What can go wrong

The triquetrum is the second most often fractured carpal, usually a small chip flaked off its back surface when the wrist bends sharply backwards — often seen alongside sprains and usually treated with splinting. Pain on the ulnar side of the wrist has several causes, so persistent symptoms are examined carefully.

Related procedures & tests

X-ray (general)

Related symptoms

Wrist pain

Related muscles

Flexor Carpi Ulnaris

Frequently asked questions

What is the cartilage disc near the triquetrum?

Part of the triangular fibrocartilage complex (TFCC), a cushion and stabiliser between the ulna and the carpus. TFCC tears are a recognised cause of pain on the little-finger side of the wrist.

Are triquetrum chip fractures serious?

Usually not: most are small, stable flakes that heal with a few weeks of splinting. They matter mainly as a clue that the wrist ligaments were stressed.

Educational information only. This atlas explains normal anatomy and describes conditions in general terms; it is not medical advice and does not replace assessment by a qualified clinician. If you have symptoms that worry you, seek medical care.