Flexor pollicis longus muscle

From Wikipedia, the free encyclopedia

Flexor pollicis longus muscle
Front of the left forearm. Deep muscles. (Flexor pollicis longus is shown in blue)
Latin	musculus flexor pollicis longus
Gray's	subject #125 449
Origin	The middle 2/4 of the volar surface of the radius and the adjacent interosseus membrane. (Also occasionally a small origin slightly on the medial epicondyle of the ulna.)
Insertion	The base of the distal phalanx of the thumb
Artery:	Anterior interosseus artery
Nerve:	Anterior interosseous nerve (branch of median nerve) (C8, T1)
Action:	Flexion of the thumb.
Antagonist:	Extensor pollicis longus muscle, Extensor pollicis brevis muscle
Dorlands /Elsevier	m_22/12549138

The flexor pollicis longus is a muscle in the forearm and hand that flexes the thumb. It lies in the same plane as the flexor digitorum profundus.

Contents 1 Origin and insertion 2 Relations 3 Actions 4 Variations 5 Additional images 6 External links

[edit] Origin and insertion

It arises from the grooved anterior surface of the body of the radius, extending from immediately below the tuberosity and oblique line to within a short distance of the pronator quadratus muscle.

It arises also from the adjacent part of the interosseous membrane of the forearm, and generally by a fleshy slip from the medial border of the coronoid process of the ulna, or from the medial epicondyle of the humerus.

The fibers end in a flattened tendon, which passes beneath the flexor retinaculum of the hand through the carpal tunnel. It is then lodged between the lateral head of the flexor pollicis brevis and the oblique part of the adductor pollicis, and, entering an osseoaponeurotic canal similar to those for the flexor tendons of the fingers, is inserted into the base of the distal phalanx of the thumb.

[edit] Relations

The anterior interosseous nerve (a branch of the median nerve) and the anterior interosseous artery and vein pass downward on the front of the interosseous membrane between the flexor pollicis longus and flexor digitorum profundus. Injuries to tendons are particularly difficult to recover from due to the limited blood supply they receive.

[edit] Actions

The flexor pollicis longus is a flexor of the phalanges of the thumb; when the thumb is fixed, it assists in flexing the wrist.

[edit] Variations

Slips may connect with flexor digitorum superficialis, flexor digitorum profundus, or the pronator teres. An additional tendon to the index finger is sometimes found.

[edit] Additional images

Bones of left forearm. Anterior aspect.	Bones of the left hand. Volar surface.	Cross-section through the middle of the forearm.	Transverse section across distal ends of radius and ulna.
Transverse section across the wrist and digits.	The mucous sheaths of the tendons on the front of the wrist and digits.	The muscles of the left hand. Palmar surface.	Ulnar and radial arteries. Deep view.
Nerves of the left upper extremity.

[edit] External links

• LUC fpl
• 221577223 at GPnotebook
• Flexor+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)