Extensor pollicis longus muscle

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Extensor pollicis longus muscle
The mucous sheaths of the tendons on the back of the wrist. (Extensor pollicis longus visible at center right.)
Latin	musculus extensor pollicis longus
Gray's	subject #125 455
Origin	ulna
Insertion	thumb, distal phalanx
Artery:
Nerve:	posterior interosseus nerve (branching from the radial nerve)
Action:	extension of the thumb (metacarpophalangeal and interphalangeal)
Antagonist:	Flexor pollicis longus muscle, Flexor pollicis brevis muscle
Dorlands /Elsevier	m_22/12548955

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

Contents 1 Origin and insertion 2 Relations 3 Action 4 Additional images 5 External links

[edit] Origin and insertion

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 pollicis brevis 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.

[edit] Relations

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

[edit] Action

The extends the proximal phalanx, and the

Extensor pollicis longus extends the terminal phalanx of the thumb; in combination with the Extensor pollicis brevis, it helps to extend and abduct the wrist.

[edit] Additional images

Anatomical snuff box	Bones of left forearm. Posterior aspect.	Bones of the left hand. Dorsal surface.	Tendons of forefinger and vincula tendina.
Cross-section through the middle of the forearm.	Posterior surface of the forearm. Superficial muscles.	Posterior surface of the forearm. Deep muscles.	Transverse section across the wrist and digits.
Arteries of the back of the forearm and hand.

[edit] External links

• LUC epl
• 33947649 at GPnotebook
• Extensor+pollicis+longus+muscle at eMedicine Dictionary
• PTCentral

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.

v • d • e List of muscles of upper limbs VERTEBRAL COLUMN trapezius - latissimus dorsi - rhomboid (major, minor) - levator scapulae THORACIC WALLS pectoralis major - pectoralis minor - subclavius - serratus anterior SHOULDER deltoid - rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) - teres major ARM anterior compartment: coracobrachialis - biceps brachii - brachialis posterior compartment: triceps brachii - anconeus FOREARM anterior compartment: superf. - pronator teres - palmaris longus - flexor carpi radialis - flexor carpi ulnaris - flexor digitorum superficialis anterior compartment: deep - pronator quadratus - flexor digitorum profundus - flexor pollicis longus posterior compartment: superf. - mobile wad (brachioradialis, extensor carpi radialis longus and brevis) - extensor digitorum, - extensor digiti minimi - extensor carpi ulnaris posterior compartment: deep - supinator - anatomical snuff box (abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) - extensor indicis HAND lateral volar - thenar (opponens pollicis, flexor pollicis brevis, abductor pollicis brevis) - adductor pollicis medial volar - hypothenar (opponens digiti minimi, flexor digiti minimi brevis, abductor minimi digiti) - palmaris brevis intermediate - lumbrical - interossei (dorsal, palmar)