Wrist Anatomy

There are 15 bones that form connections from the end of the forearm to the hand. The wrist itself contains eight small bones, called carpal bones. These bones are grouped in two rows across the wrist. The proximal row is where the wrist creases when you bend it. Beginning with the thumb-side of the wrist, the proximal row of carpal bones is made up of the scaphoid, lunate, and triquetrum. The second row of carpal bones, called the distal row, meets the proximal row a little further toward the fingers. The distal row is made up of the trapezium, trapezoid, capitate, hamate, and pisiform bones.

The proximal row of carpal bones connects the two bones of the forearm, the radius and the ulna, to the bones of the hand. The bones of the hand are called the metacarpal bones. These are the long bones that lie within the palm of the hand. The metacarpals attach to the phalanges, which are the bones in the fingers and thumb.

 

All of the nerves that travel to the hand cross the wrist. Three main nerves begin together at the shoulder: the radial nerve, the median nerve, and the ulnar nerve. These nerves carry signals from the brain to the muscles that move the arm, hand, fingers, and thumb.

Two important ligaments support the sides of the wrist. These are the collateral ligaments. There are two collateral ligaments that connect the forearm to the wrist, one on each side of the wrist.