Abductor pollicis longus

Anatomy

Origin:
Middle thirds of posterior of radius and ulna and intervening interosseus membrane.

Insertion:
Lateral aspect of base of 1st metacarpal.

Key Relations:
-Its tendon together with the tendon of extensor pollicis brevis forms the anterior boundary of the anatomical snuff box.
-One of the six muscles in the deep posterior compartment of the forearm.

Functions

-Abducts the thumb at the first carpometacarpal joint.
-Extends the thumb at the first carpometacarpal joint.

e.g. to give something the thumbs up/approve of an idea..

Supply

Nerve Supply:
Posterior interosseous nerve (C7,C8) (continuation of deep branch of the radial nerve).

Blood Supply:
Posterior Interosseous artery.

Clinical

Is affected in radial nerve palsy.

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