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| Abductor pollicis longus muscle | |
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| Front of right upper extremity. (Abductor pollicis longus labeled at upper left.) | |
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| The mucous sheaths of the tendons on the back of the wrist. (Abductor pollicis longus and brevis visible at center right, going into thumb.) | |
| Latin | musculus abductor pollicis longus |
| Gray's | subject #125 455 |
| Origin | ulna, radial styloid process |
| Insertion | first metacarpal |
| Artery | |
| Nerve | Posterior interosseous nerve |
| Action | abduction, extension of thumb |
| Antagonist | Adductor pollicis muscle |
The Abductor pollicis longus lies immediately below the Supinator and is sometimes united with it.
Contents |
Origin and insertion
It arises from the lateral part of the dorsal surface of the body of the ulna below the insertion of the Anconæus, from the interosseous membrane, and from the middle third of the dorsal surface of the body of the radius.
Passing obliquely downward and lateralward, it ends in a tendon, which runs through a groove on the lateral side of the lower end of the radius, accompanied by the tendon of the Extensor pollicis brevis, and is inserted into the radial side of the base of the first metacarpal bone.
It occasionally gives off two slips near its insertion: one to the greater multangular bone and the other to blend with the origin of the Abductor pollicis brevis.
Action
The chief action of abductor pollicis longus is to abduct the thumb at its CMC joint, thereby advancing the 1st digit anterior relative to the palm of the hand.
By its continued action it helps to extend and abduct the wrist.
Variations
More or less doubling of muscle and tendon with insertion of the extra tendon into the first metacarpal, the greater multangular, or into the Abductor pollicis brevis or Opponens pollicis.
See also
Additional images
 Bones of left forearm. Posterior aspect. |
 Bones of the left hand. Volar surface. |
 Tendons of forefinger and vincula tendina. |
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 Cross-section through the middle of the forearm. |
 Posterior surface of the forearm. Superficial muscles. |
 Posterior surface of the forearm. Deep muscles. |
 Transverse section across distal ends of radius and ulna. |
 Transverse section across the wrist and digits. |
 The muscles of the thumb. |
 The radial and ulnar arteries. |
 Deep palmar nerves. |
External links
- LUC abpl
- 731512832 at GPnotebook
- Abductor+pollicis+longus+muscle at eMedicine Dictionary
- PTCentral
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Wikipedia content modification information:
- This page was last modified on 30 July 2008, at 00:58.
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