Trapezium

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

• The most lateral bone of the distal row of carbal bones
• Located between the Scaphoid and the first metacarpal bone

Anatomic Description

• Palmar surface which contains a medial groove and prominent tubercle
• Dorsal surface is elongated and rough
• Lateral surface is large
• Medial surface is concave
• Dorso-lateral surface projects distally between the thumb and index metacarpals, has a facet articulating with the index metacarpal base
• Small concave proximal surface

Articulations

• Scaphoid at the mid-carpal joint
• Trapezoid at its inter-carpal joint
• Thumb metacarpal at the carpo-metacarpal joint of the thumb

Ligament Attachments

• Flexor Retinaculum
• Radial collateral ligament
• Capsule of the carpo-metacarpal joint of the thumb

Vascular Supply

• Distal branches of the Radial Artery

Innervation

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

---

Clinical Significance

• Trapezium Fracture

---

See Also

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

---