The Bones of the Hand
Similar to the tarsus on the foot, the basal bones of the hand form a mass called the carpus. The next rank of bones is that of the metacarpals, followed by the phalanges.
The central two bones of the carpus, roughly in line with the third metacarpal, are the lunate ("LOO-nate," moon-shaped) and capitate ("CAP-it-tate," head-shaped) bones. These two bones, taken as a midline, divide the rest of the carpus into two groups of three bones.
On the thumb-side are the scaphoid, trapezoid, and trapezium, arranged in a triangle that projects the thumb away from the hand. The scaphoid and trapezium project downward to form this side of the carpal arch.
On the little-finger side are the triangular, hamate, and pisiform bones, arranged with pisiform underneath triangular. A process called the hook of the hamate projects downward, making its height equal to that of the other two combined. These projections form the other side of the carpal arch.
Beyond this, the arrangement of the bones is similar to the foot. The heads of the metacarpals are the distal ends, the bases are proximal. The thumb has two phalanges, the fingers have three. The middle finger is always the longest, followed - with exceptions - by the ring, index, and little finger.