Extensor retinaculum of the hand
Encyclopedia
The extensor retinaculum (dorsal carpal ligament, or posterior annular ligament) is an anatomical term for the thickened part of the antebrachial fascia
that holds the tendons of the extensor muscles in place. It is located on the back of the forearm
, just proximal to the hand. It is continuous with the palmar carpal ligament
, which is located on the anterior side of the forearm.
It is a strong, fibrous band, extending obliquely downward and medialward across the back of the wrist
, and consisting of part of the deep fascia of the back of the forearm, strengthened by the addition of some transverse fibers.
The extensor retinaculum is attached laterally to the lateral margin of the radius. However, it is not attached to the ulna medially, as the distance between these two bones varies with supination and pronation of the forearm. Instead the medial attachment is to the most medial of the carpal bones, the triquetrum (or triquetral bone
) and pisiformis (or pisiform bone
). The retinaculum is also attached in its passage across the wrist, to the ridges on the dorsal surface of the radius.
Antebrachial fascia
The antebrachial fascia continuous above with the brachial fascia, is a dense, membranous investment, which forms a general sheath for the muscles in this region; it is attached, behind, to the olecranon and dorsal border of the ulna, and gives off from its deep surface numerous intermuscular...
that holds the tendons of the extensor muscles in place. It is located on the back of the forearm
Forearm
-See also:*Forearm flexors*Forearm muscles...
, just proximal to the hand. It is continuous with the palmar carpal ligament
Palmar carpal ligament
The palmar carpal ligament is a term that is often used in anatomy to describe the thickened portion of antebrachial fascia on the anterior of the wrist. It is officially unnamed....
, which is located on the anterior side of the forearm.
It is a strong, fibrous band, extending obliquely downward and medialward across the back of the wrist
Wrist
In human anatomy, the wrist is variously defined as 1) the carpus or carpal bones, the complex of eight bones forming the proximal skeletal segment of the hand;...
, and consisting of part of the deep fascia of the back of the forearm, strengthened by the addition of some transverse fibers.
The extensor retinaculum is attached laterally to the lateral margin of the radius. However, it is not attached to the ulna medially, as the distance between these two bones varies with supination and pronation of the forearm. Instead the medial attachment is to the most medial of the carpal bones, the triquetrum (or triquetral bone
Triquetral bone
The triquetral bone is located in the wrist on the medial side of the proximal row of the carpus between the lunate and pisiform bones. It is on the ulnar side of the hand, but does not articulate with the ulna...
) and pisiformis (or pisiform bone
Pisiform bone
The pisiform bone is a small knobbly, pea-shaped wrist bone.The pisiform bone is found in the proximal row of the carpus. It is located where the ulna joins the carpus...
). The retinaculum is also attached in its passage across the wrist, to the ridges on the dorsal surface of the radius.