Trapezoid

A small, complex bone located in the wrist, important for wrist stability and movement.

The trapezoid is one of the eight carpal bones found in the wrist. It is specifically classified as a distal bone, located between the trapezium and the capitate bones. Its unique shape resembles a trapezoid, which is where its name is derived from. The bone plays a critical role in the wrist's structure, allowing for a range of motion in the hand.

Terminologia Anatomica

os trapezoideum

System

Skeletal system

Function

The trapezoid bone supports the wrist and contributes significantly to hand movements. It articulates with surrounding bones, providing stability and enabling the intricate motions required in activities such as gripping and grasping. The trapezoid helps facilitate the flexion, extension, and lateral movements of the wrist, making it essential for both fine motor tasks and powerful grips. Its position provides a base of support for the second metacarpal, allowing for optimal mobility and functionality of the index finger. This bone also acts as a key conduit for the transfer of forces as they pass through the wrist, contributing to overall wrist dexterity.

Location

The trapezoid bone is located on the palm side of the wrist, in the distal row of the carpal bones. It is positioned medially to the trapezium bone and laterally to the capitate bone, forming part of the wrist joint. Specifically, it sits proximal to the second metacarpal, which is the bone of the index finger. This strategic location places it at the heart of the wrist, where it can effectively facilitate both motion and stability in the hand.

Did You Know?

The trapezoid is often overlooked due to its small size, yet it plays a critical role in the wrist's function when performing precise hand movements.
In some ancient cultures, wrist injuries were believed to be linked with the presence of 'evil spirits', emphasizing the importance of the wrist's functionality for daily life.
Injuries to the trapezoid bone can lead to significant wrist pain and swelling, impacting overall hand mobility and strength.