Anatomy of the Wrist

The wrist begins in the forearm and ends just before the fingers. The wrist consists of bones, capsules and ligaments, muscles, tendons, nerves, and blood vessels. Together, they ensure that we can move the hand well and support weight on it.

Bones

The forearm consists of two bones, the radius and the ulna. The ends of these two bones form one (één) half of the wrist. The other half is formed by the carpal and metacarpal bones, which are part of the hand.

In between lies the triangular fibrocartilage complex (TFCC). This complex consists of a cartilage disc, ligaments, and a tendon sheath. Together, they fill the space between the ulna and the carpal bones.

These structures also connect the ulna, the radius, and one (één) of the carpal bones (os triquetrum) with each other. The TFCC is intended to give the wrist more stability and to absorb forces placed on the wrist.

Capsule and ligaments

A large part of the wrist's stability comes from the surrounding capsule and ligaments. These ligaments are divided into two groups: intrinsic and extrinsic ligaments.

Intrinsic ligaments are short and stiff and connect one carpal bone to another.

Extrinsic ligaments are longer, begin on the bones of the forearm, and then run over multiple bones. These ligaments are less stiff and therefore allow a bit more movement. In this way, a network of ligaments and bands provides both the stability of the wrist and allows movement at the same time.

Muscles

The muscles that move the wrist are located for the most part in the forearm. From there, they run via long tendons over the wrist. The muscles that flex the wrist are on the palm side; the muscles that extend the wrist are on the back of the hand.

Nerves

The nerves that enable muscles to move and provide sensation in the hand also run across the wrist. The following three nerves are found here: the ulnar, the radial, and the median nerve.

The median nerve runs, together with nine tendons, through the carpal tunnel. This is a small tunnel on the palm side of the wrist, formed by carpal bones and a ligament that runs over them. This part of the wrist plays an important role in carpal tunnel syndrome.

Blood vessels

Two important blood vessels run over the wrist to the fingers: the ulnar and radial arteries. The latter can be used to measure the pulse.