Trapezoid bone

The carpal bones function as a unit to provide a bony superstructure for the hand.^{[1] : 708}

Clinical Significance

Isolated fractures of the trapezoid are rare, representing 0.4% of the total, thus being the least common of all carpal fractures. This is due to the bone being in a fairly protected position. Distally, it forms a stable, relatively immobile joint with the second metacarpal, radially and proximally it forms strong ligaments with the trapezium and the capitate ulnarly, scaphoid respectively.

However, injury can occur through axial force applied to the second metacarpal base. Subluxations, such as ones caused by delivering a blow, are not uncommon. Direct trauma to the bone can also cause fracture.

Due to its rarity, standard treatment has not been established. A wide range of treatments are possible, including rest, surgery and casting.^[2]

History

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."

Additional images

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  Position of trapezoid bone (shown in red). Left hand. Animation.
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  Trapezoid bone of the left hand. Close up. Animation.
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  Trapezoid bone.
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  Right hand posterior view (dorsal view). Thumb on bottom.
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  Trapezoid shown in yellow. Left hand. Dorsal surface.
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  Trapezoid shown in yellow. Left hand. Palmar surface.
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  Transverse section across the wrist (palm on top, thumb on left). Trapezoid bone shown in yellow (labelled as "Lesser Multang").
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  Cross section of wrist (thumb on left). Trapezoid shown in red (labelled as "Lesser Multang").

See also

Wikimedia Commons has media related to Trapezoid bone.

• Carpal bone

References

This article incorporates text in the public domain from page 225 of the 20th edition of Gray's Anatomy (1918)