Muscle Name: extensor pollicis longus

AKA:  musculus extensor pollicis longus

Abbreviation:  EPL

Spinal Nerve Roots:
    C7
    C8

Brachial Plexus Trunks:
    middle trunk
    lower trunk

Brachial Plexus Cords:
    posterior cord

Named Nerves:
    radial nerve

Proximal Attachment:  ulna  

Distal Attachment:  thumb, distal phalanx

Action:  extension of the thumb (metacarpophalangeal and interphalangeal)

Needle Insertion:  In the pronated forearm, midway between the styloid process and the lateral epicondyle, just lateral to the ulna bone and deep to the extensor indicis communis.

Activation for EMG:  Extend the thumb.

Pitfalls:  If the needle is placed to distal or close to the radial bone, the extensor pollicis brevis will be sampled.

Notes: