Triquetrum

Description

Normal anatomy of the carpal bones. Diagram of the wrist (frontal view) shows the eight carpal bones and the three carpal arcs (Gilula arcs), which are shown as pink (arc I), blue (arc II), and red (arc III) lines. C (capitate), H (hamate), L (lunate), P (pisiform), S (scaphoid), Tm (trapezium), Td (trapezoid), Tr (triquetrum)

Wrist radiograph with carpal bones labeled

General

• Known as the triangular bone and has a pyramidal shape.
• Forms part of the proximal carpal row.
• Located between the Lunate and the Pisiform.

Anatomic Description

• Superior surface has a medial non-articular portion, and a lateral convex portion that articulates with the Articular disk of the wrist.
• Inferior surface is directed lateralward, and it articulates with the Hamate.
• Dorsal surface is rough for the attachment of ligaments.
• Lateral surface which is the base of the pyramid is for the articulation with the Lunate.
• Medial surface the apex of the pyramid is for the attachment of the Ulnar Collateral Ligament of the wrist.

Articulations

• Scaphoid and Lunate forming the distal articular surface of the radio-carpal joint.
• Lunate lateral
• Pisiform lateral
• Hamate distal

Ligament Attachments

• Luno-triquetral ligament
• Ulno-triquetral ligaments
• Ulnar collateral ligament

Vascular Supply

• Network of nutrient vessels on non-articular surfaces

Innervation

• Anterior interosseous branch of the median nerve
• Posterior interosseous branch of the radial nerve
• Dorsal and the deep branches of the ulnar nerve

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Clinical Significance

• Triquetrum Fracture
• Lunotriquetral Instability

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See Also

• Hand and Wrist Anatomy (Main)
• Hand And Wrist Anatomy
• Wrist Pain (Main)

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