Os trapezoideum

Os Trapezoideum

The Os Trapezoideum is one of the eight carpal bones in the human wrist. It is located in the distal row of the carpal bones, which are situated in the lower part of the wrist, closer to the fingers. The os trapezoideum is named for its trapezoid shape and is the smallest bone in the distal row.

Anatomy

The os trapezoideum is situated between the os scaphoideum and the os capitatum. It is bordered by the os trapezium on its radial side and the os capitatum on its ulnar side. The bone is distinguished by its wedge shape, which is broad on one side and narrows towards the other.

The os trapezoideum articulates with four bones: the second metacarpal bone, the os trapezium, the os scaphoideum, and the os capitatum. The articulation with the second metacarpal bone is the largest and most significant, forming the trapezoid-second metacarpal joint.

Function

The os trapezoideum, like other carpal bones, contributes to the flexibility and movement of the wrist. It plays a crucial role in the stability of the carpal bone structure and the transmission of force from the hand to the forearm.

Clinical Significance

Injuries to the os trapezoideum are relatively rare due to its protected position within the wrist. However, fractures can occur, typically as a result of direct trauma or a fall onto an outstretched hand. Diagnosis is often challenging due to the small size of the bone and its proximity to other structures. Treatment typically involves immobilization, but surgery may be required in severe cases.

See Also

• Carpal bones
• Wrist
• Hand