Lunate

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

Alternative Names

• Lunate Bone
• Os Lunatum
• Semilunar Bone
• Lunar Bone
• Intermediate Proximal Carpal Bone

General

• The word Lunate is derived from the Latin word Luna meaning crescent-shaped or moon.
• Situated in the center of the proximal row of the Carpus.
• Located between the Scaphoid and Triquetrum.

Anatomic Description

• The superior surface is convex and smooth that articulates with the Radius.
• The inferior surface is deeply concave articulating with the head of the Capitate and the Hamate.
• The lateral surface has a narrow, semilunar facet for articulation with the Scaphoid.
• The medial surface has a smooth facet, for articulation with the Cuneiform.

Function

• Provide osseous structure to the wrist
• Involved in movement of the wrist

Articulations

• Radius proximally
• Capitate and Hamate distally
• Scaphoid laterally
• Triquetrum medially

Ligament Attachments

• Scapholunate Ligament
• Luno-triquetral Ligament
• Radio-luno-triquetral Ligament
• Radio-scapho-lunate Ligament
• Ulno-lunate ligaments

Vascular supply

• Branches from the dorsal radiocarpal arch and dorsal intercarpal arch

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

Pathology

• Lunate Fracture
• Lunate Dislocation
• Kienbocks Disease (AVN of the lunate)
• Scapholunate Instability
• Lunotriquetral Instability
• Perilunate Dislocation
• Carpal Instability
• Radiocarpal Arthritis

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See Also

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

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