The carpal bones are the eight wrist bones, which make up the base of the human hand. They are small and very irregular in shape as they are tightly held together by cartilage and strong ligaments (bands of connective tissue). They are set in two rows and all together are called the carpus, lying between the distal end of radius-ulna bones and the metacarpal bones, with which they articulate.
In the proximal row, there are the scaphoid, lunate, triquetral, and pisiform (the smallest one). The scaphoid and the lunate bone articulate with the radius, while the pisiform and triquetral bone with the ulna. In the distal row, there are the trapezium, trapezoid, capitate, and hamate, which articulate with the metacarpus.
The metacarpal bones have rough spots on the palmar and dorsal sides which indicate the sites of attachment for the hand muscles tendons. Except for the pisiform, the rest of the wrist bones have six surfaces or facets, most of which articulate with other bones. The capitate, the scaphoid, and the hamate are the biggest and strongest ones.
Below, diagram of the carpal and metacarpal bones (palmar aspect of right hand) showing all the eight bones that make up the wrist.
Below, the dorsal side of right hand, showing the wrist bones.
