The anatomy of the wrist consists of eight carpal bones, connecting to the ulna and radius at the proximal end and five metacarpal bones at the distal end, and a complex network of overlapping muscles, ligaments, tendons and nerves, notes Inner Body. The small carpal bones exist in two rows of four bones collectively called the carpus.
The carpus, rounded on its proximal end, is slightly concave on its distal end. The roundness and concavity allows it to articulate with the ulna and radius and the metacarpal bones, respectively. On the concave palmar side, the carpus forms a canal called the carpal tunnel, reports Inner Body. Tendons, ligaments and nerves extend through the carpal tunnel into the palm of the hand.
The 13 bones of the wrist participate in complex articulation using the 15 interconnecting flexor and extensor muscles, explains Inner Body. The muscles of the wrist provide flexibility, precise control and gripping strength to the hand, allowing it to perform a number of skilled operations, such as typing and playing musical instruments. As a result of wrist articulation, the hand is capable of three degrees of free movement, according to MedScape: flexing and extending, pronating and supinating, and deviating ulnarly or radially.