Trapezoid bone

Trapezoid bone

The Trapezoid bone is one of the eight carpal bones of the hand. It is located in the distal row of the carpus, between the trapezium and the capitate bone. The trapezoid bone is the smallest bone in the distal row. It may be distinguished by its wedge-like form.

Structure

The trapezoid bone is wedge-shaped, and has four surfaces. It is located between the trapezium and the capitate in the distal row of the carpal bones. The trapezoid is distinguished by a deep groove on its palmar surface. It is the least often fractured of the carpal bones.

Surfaces

The trapezoid has four surfaces: superior, inferior, lateral, and medial.

• The superior surface is quadrilateral and slightly concave. It articulates with the scaphoid bone.
• The inferior surface articulates with the proximal part of the second metacarpal bone.
• The lateral surface, convex and smooth, articulates with the trapezium.
• The medial surface, concave and smooth, articulates with the capitate.

Function

The trapezoid bone contributes to the conformation of the carpal tunnel and the carpal arch.

Clinical significance

Injuries to the trapezoid are rare. When they do occur, they are often associated with fractures of other carpal bones.

See also

• Carpal bones
• Hand
• Scaphoid bone
• Trapezium (bone)
• Capitate bone

External links

• Trapezoid bone at the US National Library of Medicine Medical Subject Headings (MeSH)

Trapezoid bone Resources
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