Supinator muscle
| Supinator muscle |
|---|
|
| origin |
| Epicondylus lateralis humeri , lateral surface of the ulna , lig. Annulare radii |
| approach |
| Front face of the radius |
| function |
| Forearm supination |
| Innervation |
| Radial nerve |
| Spinal segments |
| C6-C8 |
| Classification according to ICD-10 | |
|---|---|
| G56.3 | Upper extremity mononeuropathies, radial nerve lesion, supinator syndrome |
| ICD-10 online (WHO version 2019) | |
The supinator muscle ( Latin for "turning away from home") is one of the deep skeletal muscles of the forearm . In humans, it arises as the only muscle in this layer on the humerus . The deep branch ( ramus profundus ) of the radial nerve pierces it.
In the ungulates the muscle is not developed or only rudimentary (pigs). A rotation of the radius around the ulna is impossible because of the adhesions.
function
The supinator muscle supinates the forearm, i. That is, it rotates around the longitudinal axis of the forearm so that the thumb points outwards. If it fails, supination is no longer possible with the elbow joint extended . (When the elbow joint is flexed, the biceps brachii muscle also supinates .)
Supinator syndrome
In hypertrophy of the musculus supinator it can to compression of the deep branch of the radial nerve to come. As a result, it can be paralyzed, but the ramus profundus does not innervate any extensor muscles of the forearm in addition to the musculus supinator, but only some extensors in the hand ( musculus abductor pollicis longus , musculus extensor pollicis brevis , musculus extensor pollicis longus , musculus extensor indicis ) and is not afferent , which means that the “ hand drop ” does not appear and there are no sensory disorders, only weakness in extension and abduction in the thumb.
For decompression, the lateral origin of the supinator muscle is usually severed.