Lunate bone

Accessory

ossicles of the wrist • Ossicles of the wrist and hand - Ganzer Fall bei Radiopaedia

Jones J, Ossicles of the wrist and hand. Case study, Radiopaedia.org (Accessed on 23 Nov 2022) https://doi.org/10.53347/rID-24102 • CC by-nc-sa 3.0 (modified)

Dorsal

intercalated segment instability • Dorsal and volar intercalated segmental instability and normal carpal bone anatomy (illustrations) - Ganzer Fall bei Radiopaedia

Hapugoda, S. Dorsal and volar intercalated segmental instability and normal carpal bone anatomy (illustrations). Case study, Radiopaedia.org. (accessed on 03 Nov 2022) https://doi.org/10.53347/rID-53794 • CC by-nc-sa 3.0 (modified)

Lunate •

Lunate (Gray's illustration) - Ganzer Fall bei Radiopaedia

Hacking C, Lunate (Gray's illustration). Case study, Radiopaedia.org (Accessed on 21 Jan 2023) https://doi.org/10.53347/rID-83284 • CC by-nc-sa 3.0 (modified)

Radiopaedia • CC-by-nc-sa 3.0 • de

The lunate (os lunatum or semilunar) is one of the carpal bones and is a component of the proximal carpal row.

Gross anatomy

Osteology

The lunate is crescent-shaped with a proximal convex articular facet and a distal concave articular facet. On the medial surface is a square-shaped facet and on the lateral surface is a semilunar facet. It is broader anteriorly than it is posteriorly.

Articulations

along with the scaphoid and triquetrum forms the distal articular surface of the radiocarpal joint
intercarpal articulations
- scaphoid (lateral)
- capitate (distal)
- triquetrum (medial)
- hamate (distal and medial) - only in type II lunate
articulates with the triangular fibrocartilage complex

Attachments

Musculotendinous

nil

Ligamentous

intrinsic ligaments
- scapholunate ligament
- lunotriquetral ligament
extrinsic ligaments
- palmar: radiolunotriquetral, radioscapholunate, ulnolunate ligaments

Blood supply

arterial supply: branches from the dorsal radiocarpal arch and dorsal intercarpal arch supply the lunate via the dorsal and palmar surfaces (80%) or palmar surface only (20%)

Variant anatomy

variation in articular facets (see: lunate morphology)
lunotriquetral coalition
associated accessory ossicles
- os epilunate
- os hypotriquetrum
- os hypolunatum
bipartite lunatum

Radiographic appearance

Plain radiograph

frontal projection (neutral wrist position)
- more than one-half should contact distal radial articular surface
- should have a 'square shape' and the intercarpal joints should be uniformly 1-2 mm wide
- forms part of the carpal arcs

Development

Ossification

Ossifcation typically begins at age four and is complete by age six or seven .

History and etymology

From the Latin "luna" meaning moon, referring to the crescent-moon shape of the lunate. It was first named the "lunatum" in 1653 by Lyser, and has also been termed the "lunare" or "semilunare".

Related pathology