trapezium

Bone: Trapezium (bone)
BONES OF HAND Proximal: A=Scaphoid, B=Lunate, C=Triquetral, D=Pisiform Distal: E=Trapezium, F=Trapezoid, G=Capitate, H=Hamate
Trapezium
Latin	os trapezium, os multangulum majus
Gray's	subject #54 225
Articulations	1st metacarpal distally scaphoid proximally trapezoid medially 2nd metacarpal medially
MeSH	Trapezium+Bone

The trapezium bone (greater multangular bone) is a carpal bone, in what is commonly referred to as the wrist.

The trapezium is distinguished by a deep groove on its palmar surface. It is situated at the radial side of the carpus, between the scaphoid and the first metacarpal bone. It is homologous with the first distal carpal of reptiles and amphibians.

The etymology derives from the Greek trapezion which means "irregular quadrilateral;" literally, "a little table," from trapeza meaning table. Also, from tra- "four" and peza "foot" or "edge."

Surfaces

The superior surface is directed upward and medialward; medially it is smooth, and articulates with the scaphoid; laterally it is rough and continuous with the lateral surface.

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.

The dorsal surface is rough.

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.

The medial surface presents two facets; the upper, large and concave, articulates with the trapezoid; the lower, small and oval, with the base of the second metacarpal.

Tubercle of trapezium

The tubercle of trapezium is a anatomic tubercle, where sometimes abductor pollicis brevis muscle attaches.

See also

• Bone terminology
• Terms for anatomical location
• Finger
• Hand

Additional images

Bones of the left hand. Dorsal surface.

Ligaments of wrist. Anterior view

Tendons of forefinger and vincula tendina.

Transverse section across the wrist and digits.