Extensor pollicis longus muscle

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Extensor pollicis longus muscle
Posterior surface of the forearm. Deep muscles.
Gray's subject #125
Origin:
Insertion:
Blood:
Nerve: posterior interosseus nerve (branching from the radial nerve)
Action: extension of the thumb

The Extensor pollicis longus (Extensor secundi internodii pollicis) is much larger than the Extensor pollicis brevis muscle, the origin of which it partly covers.

It arises from the lateral part of the middle third of the dorsal surface of the body of the ulna below the origin of the Abductor pollicis longus, and from the interosseous membrane.

It ends in a tendon, which passes through a separate compartment in the dorsal carpal ligament, lying in a narrow, oblique groove on the back of the lower end of the radius.

It then crosses obliquely the tendons of the Extensores carpi radialis longus and brevis, and is separated from the Extensor brevis pollicis by a triangular interval, the anatomical snuff box in which the radial artery is found; and is finally inserted into the base of the last phalanx of the thumb.

The radial artery is crossed by the tendons of the Abductor pollicis longus and of the Extensores pollicis longus and brevis.

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This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

Muscles of the HeadNeckTrunkUpper limbLower limbLIST OF ALL MUSCLES

VERTEBRAL COLUMN: trapezius | latissimus dorsi | rhomboid major | rhomboid minor | levator scapulae | (Gray's s121)

ANTERIOR AND LATERAL THORACIC WALLS: pectoralis major | pectoralis minor | subclavius | serratus anterior | (Gray's s122)

SHOULDER: deltoid | rotator cuff (subscapularis, supraspinatus, infraspinatus, teres minor) | teres major | (Gray's s123)

ARM: coracobrachialis | biceps brachii | brachialis | triceps brachii | (Gray's s124)

FOREARM: Volar super. | pronator teres | palmaris longus | flexor carpi radialis | flexor carpi ulnaris | flexor digitorum superficialis
Volar deep | flexor digitorum profundus | flexor pollicis longus | pronator quadratus
Dorsal super. | brachioradialis | extensor digitorum | extensor carpi radialis longus | extensor digiti minimi | extensor carpi radialis brevis | extensor carpi ulnaris | anconeus
Dorsal deep | supinator | abductor pollicis longus | extensor pollicis brevis | extensor pollicis longus | extensor indicis | (Gray's s125)

HAND: Lateral volar | abductor pollicis brevis | thenar (opponens pollicis, flexor pollicis brevis, adductor pollicis)
Medial volar | palmaris brevis | hypothenar (abductor minimi digiti, flexor digiti minimi brevis, opponens digiti minimi)
Intermediate | lumbrical | dorsal interossei | palmar interossei | (Gray's s126)

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