Abductor pollicis longus muscle
Abductor pollicis longus muscle |
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Hand muscles of man |
origin |
Posterior surface of the radius and ulna , interosseous membrane |
approach |
First metacarpal and basal phalanx of the thumb |
function |
Splaying the thumb |
Innervation |
Radial nerve of the brachial plexus |
Spinal segments |
C7, C8 |
The abductor pollicis longus muscle ( Latin for "long thumb spreader" or "long thumb puller") is an extensor muscle in the deep layer of the forearm . The skeletal muscle is responsible for the spreading ( abduction ) of the thumb .
Its insertion tendon runs together with that of the extensor pollicis brevis muscle through the first tendon sheath compartment of the extensor retinaculum .