Dr Yuranga Weerakkody and Dr Henry Knipe et al.

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

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. 

  • nil
  • intrinsic ligaments
  • extrinsic ligaments
    • palmar: radiolunotriquetral, radioscapholunate, ulnolunate ligaments
  • 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%) 2
  • frontal projection (neutral wrist position)
    • more than one-half should contact distal radial articular surface 3
    • should have a 'square shape' and the intercarpal joints should be uniformly 1-2 mm wide
    • forms part of the carpal arcs

Ossifcation typically begins at age four and is complete by age six or seven 2

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".

Upper limb anatomy
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Article information

rID: 26679
Section: Anatomy
Tags: wrist, cases
Synonyms or Alternate Spellings:
  • Lunate anatomy
  • Os lunatum
  • Semilunar
  • Lunate bone

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Cases and figures

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    Os epilunatum
    Figure 1: expected position os epilunate
    Drag here to reorder.
  • Drag
    Figure 2: carpal bones
    Drag here to reorder.
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