| Origin |
Posterior surface of middle 1/3 of ulna and interosseous membranee
|
| Insertion |
Base of distal phalanx of thumb
|
| Action |
Extends distal phalanx of thumb at carpometacarpal and interphalangeal joints
|
| Innervation |
Posterior interosseous nerve (C7 and C8), the continuation of the deep branch of the radial nerve (C7, C8)
|
| Arterial Supply |
Posterior interosseous artery
|
| Relevant Conditions |
DeQuervain Disease  |
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