- Flexor pollicis longus muscle
Name = Flexor pollicis longus muscle
Latin = musculus flexor pollicis longus
GraySubject = 125
GrayPage = 449
Caption = Front of the left
forearm. Deep muscles. (Flexor pollicis longus is shown in blue)
Origin = The middle 2/4 of the
volarsurface of the radiusand the adjacent interosseus membrane. (Also occasionally a small origin slightly on the medial epicondyleof the ulna.)
Insertion = The base of the
distal phalanxof the thumb
Flexionof the thumb.
Extensor pollicis longus muscle, Extensor pollicis brevis muscle
Anterior interosseus artery
Anterior interosseous nerve(branch of median nerve) (C8, T1)
DorlandsPre = m_22
DorlandsSuf = 12549138
The flexor pollicis longus is a muscle in the
forearmand handthat flexes the thumb. It lies in the same plane as the flexor digitorum profundus. This muscle is unique to humans, being "either rudimentary or absent" in other primates. [Straus, W. L. (1942). Rudimentary digits in primates. Q. Rev. Biol. 17, 228–243. ]
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 quadratusmuscle.
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 processof the ulna, or from the medial epicondyleof the humerus.
The fibers end in a flattened tendon, which passes beneath the
flexor retinaculum of the handthrough the carpal tunnel. It is then lodged between the lateral head of the flexor pollicis brevisand 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.
anterior interosseous nerve(a branch of the median nerve) and the anterior interosseous arteryand 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.
The flexor pollicis longus is a flexor of the phalanges of the thumb; when the thumb is fixed, it assists in flexing the wrist.
Slips may connect with
flexor digitorum superficialis, flexor digitorum profundus, or the pronator teres. An additional tendon to the index finger is sometimes found.
* [http://www.ptcentral.com/muscles/musclearms.html#flexor%20pollicis%20longus PTCentral]
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