Left hand anterior view (palmar view). Trapezoid bone shown in red.
The left trapezoid bone.
|Latin||os trapezoideum, os multangulum minus|
|Articulations||articulates with four bones:
second metacarpal distally
trapezium bone laterally
|Anatomical terms of bone|
The trapezoid bone (lesser multangular bone) is a carpal bone in tetrapods, including humans. It is the smallest bone in the proximal row. It may be known by its wedge-shaped form, the broad end of the wedge constituting the dorsal, the narrow end the palmar surface; and by its having four articular facets touching each other, and separated by sharp edges. It is homologous with the "second distal carpal" of reptiles and amphibians.
The inferior surface articulates with the proximal end of the second metacarpal bone; it is convex from side to side, concave from before backward and subdivided by an elevated ridge into two unequal facets.
The etymology derives from the Greek trapezion which means "irregular quadrilateral," from tra- "four" and peza "foot" or "edge." Literally, "a little table" from trapeza meaning "table" and -oeides "shaped."
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- This article uses anatomical terminology; for an overview, see anatomical terminology.