The trapezoid bone structure forms a firm, fairly stationary joint with the second metacarpal base. The trapezoid is shaped like a keystone, and is the least frequently injured carpal bone. The structure of the trapezoid places it in a rather sheltered place. The trapezoid is two times wider dorsally than it is palmarly. It has been shown that the trapezoid lacks internal anastamoses, but has several sources of blood supply. Axial force, while applied to the second metacarpal base, can cause the trapezoid bone structure to become injured or even to fracture. People with trapezoid fractures tend to moan about pain at the base of the second metacarpal. The outcome of pain can be wrist swelling and decreased range of motion. Standard treatment is not yet available as trapezoid fractures are a rare occurrence. However, sometimes a doctor will recommend the removal of a small fragment of trapezoid. In other cases, fractures of the trapezoid can involve open reduction and internal fixation.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Trapezoid