Arranged in two rows, there are eight carpal bones in the human wrist, and they are located between the metacarpals and the ends of the radius and ulna bones. The trapezium rests in the row closest to the metacarpals, with the scaphoid located directly behind it and the trapezoid to its side. The trapezium has three surfaces providing articulation points with other bones. The superior surface faces an upward and medial direction and articulates with the scaphoid. The inferior features more of an oval shape, as it articulates the first metacarpal bone. The trapezoid carpal articulates the trapezium through the medial surface. This carpal also provides an origination point for the oppenens pollicis and abductor pollicis, both of which assist in moving the thumb. Most of the muscular tissues attach to the bone's palmar surface. The lateral surface provides a notable exception, as there are many ligaments in this broad and rough area. The dorsal side of the trapezium features a smooth surface, but does not serve as many functions as its counterparts.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Trapezium