The trapezoid bone is one of eight carpal bones that forms part of the wrist joint. The word trapezoid is derived from the Greek word trapezion which means “a little table” of “irregular quadrilateral”. It is a wedge-shaped carpal bone that resembles the trapezium. It is also called the lesser multangular bone.
The trapezoid is situated in the distal row of carpal bones and is the smallest of these bones. It is wedge-shaped with four articular facets.
The trapezoid, together with the other carpal bones give bony structure to the wrist and hand. Being part of the distal row of carpal bones, it gives structure to specifically the palm of the hand.
There are no muscle attachments onto the trapezoid. However, there are ligaments that attach to this bone. Interosseus ligaments between the trapezoid and the trapezium, capitate and scaphoid respectively. Due to these ligaments and its position in the distal row of carpal bones, it is fairly protected from injury.