Bone and Joint
The bones in the hand align precisely to provide a full range of motion and precision. When one of the bones is injured, it can force the entire hand out of alignment. There are 27 bones in the hand – eight in the wrist, called the carpals; five in the palm of the hand, called the metacarpals; and 14 bones in the fingers, called the proximal, middle, and distal phalanges. The two bones of the forearm, the radius and ulna also make up part of the wrist joint.
The ability to move our fingers with precision enables us to perform a wide variety of everyday tasks. This precise motion is made possible by the joints in the hand, which enable the fingers to bend. The joints in the fingers are the proximal interphalangeal (PIP) joints, located between the proximal and middle phalanges (finger bones), and the distal interphalangeal (DIP) joints, located between the middle and distal phalanges.
In addition to the joints in the fingers themselves, there are also metacarpophalangeal (MCP) joints in the hand where the proximal phalanges meet the metacarpal bones in the palm. In the wrist, each of the carpal bones has an associated joint – the radiocarpal, intercarpal, midcarpal, carpometacarpal, and intermetacarpal joints. There is also the distal radioulnar joint (DRUJ) between the radius and ulna (forearm bones).
