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|Left hand anterior view (palmar view). Trapezium shown in red.|
|The left trapezium bone|
|Latin||Os trapezium, os multangulum majus|
|Gray's||subject #54 225|
|Articulations||1st metacarpal distally
2nd metacarpal medially
The trapezium is distinguished by a deep groove on its anterior surface. It is situated at the radial side of the carpus, between the scaphoid and the first metacarpal bone (the metacarpal bone of the thumb). It is homologous with the first distal carpal of reptiles and amphibians.
The etymology derives from the Greek trapezion which means "a little table", from trapeza meaning "table", itself from (te)tra- "four" and pod- "foot".
The inferior surface is oval, concave from side to side, convex from before backward, so as to form a saddle-shaped surface for articulation with the base of the first metacarpal bone. This saddle-shaped articulation is partially responsible for the thumb's opposable motion.
The dorsal surface is smooth.
The palmar surface is narrow and rough. At its upper part is a deep groove, running from above obliquely downward and medialward; it transmits the tendon of the Flexor carpi radialis, and is bounded laterally by an oblique ridge. This surface gives origin to the Opponens pollicis and to the Abductor and Flexor pollicis brevis; it also affords attachment to the transverse carpal ligament.
The lateral surface is broad and rough, for the attachment of ligaments.
Tubercle of trapezium
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