Proximal wrist

The proximal wrist, which is closer to the center of the body, is formed by joint surfaces of: Together they form the Articulatio radiocarpalis. The capsule of the joint is limp and thin. On the side of the back of the hand (dorsal) the joint capsule is reinforced by various ligaments.

The collateral ligaments between the carpal bone and ulna or radius provide stability. In addition, 2 ligaments between the carpal bone and the radius strengthen the wrist from above and below (Ligamentum radiocarpale palmare and dorsale). The entire joint has an elliptical structure (ellipsoid joint or ovoid joint) and thus permits 2 different movements (2 degrees of freedom): flexion (palmar flexion) and extension (dorsal extension), as well as spreading in two directions (ulnar abduction and radial abduction).

The proximal wrist is mainly responsible for flexion (palmar flexion), while the distal wrist is mainly responsible for extension (dorsal extension).

Ulna (ulna)
Spoke (radius)
Close to the body row of carpal bones (proximal carpal bones) consisting of the 3 carpal bones scaphoid bone (Os scaphoideum), lunate bone (Os lunatum) and triangular bone (Os triquetrum).

The distal wrist remote from the center of the body is formed by the two rows of carpal bones (proximal and distal row). Between the individual carpal bones, a joint gap is thus formed, which is S-shaped.

A joint capsule is also found here. The capsule is rather tight on the inside of the hand, but rather slack on the back of the hand. The distal wrist is an interlocked hinge joint, which is strongly restricted in its movement due to its curved course, the ligaments and joint capsule. It functions together with the proximal wrist as a functional unit. While the proximal wrist is mainly involved in flexion (palmar flexion), the distal wrist is particularly involved in extension (dorsal extension).

Articulationes intercarpales

These are the individual small joints between the carpal bones of a row.The individual bones are tightly fixed by various ligaments (Ligg. Intercarpalia interossea). The connections of the distal row (amphiarthroses) are particularly tight.