Trapezium (bone)

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

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

Tubercle of trapezium

The tubercle of trapezium is a tubercle found on the anterior surface of the bone.^[1]: 708 It is where sometimes abductor pollicis brevis muscle attaches.

Function

The carpal bones function as a unit to provide a bony superstructure for the hand. The trapezium is the most radial of the bones surrounding the carpal tunnel.^[1]: 708 It is important in thumb movement.^[2]

Clinical relevance

The trapezium is susceptible to arthritis at the joint with the

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 name was first documented in 1840.[3]

Additional images

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  Position of trapezium (shown in red). Left hand. Animation.
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  Trapezium of the left hand.
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  Trapezium bone.
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  Right hand posterior view (dorsal view). Thumb on bottom.
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  Right hand anterior view (palmar view). Thumb on top.
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  Bones of the left hand. Palmar surface. Trapezium shown in yellow.
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  Bones of the left hand. Dorsal surface. Trapezium shown in yellow.
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  Cross section of wrist (thumb on left). Trapezium shown in red (labelled as "Greater Multang").
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  Transverse section across the wrist and digits. Trapezium is shown in yellow (labelled as "Greater Multang").
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  Ligaments of wrist. Anterior view
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  Tendons of forefinger and vincula tendina.

See also

Wikimedia Commons has media related to Trapezium (bone).

• Carpal bone
• Finger
• Hand

References