Flexor pollicis brevis muscle
| Flexor pollicis brevis muscle | |
|---|---|
 Superficial muscles of the left hand, palmar view. | |
| Details | |
| Origin | Trapezium, flexor retinaculum |
| Insertion | Thumb, proximal phalanx |
| Artery | Superficial palmar arch |
| Nerve | Recurrent branch of the median nerve, deep branch of ulnar nerve (medial head) |
| Actions | Flexes the thumb at the first metacarpophalangeal joint |
| Antagonist | Extensor pollicis longus and brevis |
| Identifiers | |
| Latin | musculus flexor pollicis brevis |
| TA98 | A04.6.02.055 |
| TA2 | 2522 |
| FMA | 37378 |
| Anatomical terms of muscle | |
The flexor pollicis brevis is a muscle in the hand that flexes the thumb. It is one of three thenar muscles.[1][2] It has both a superficial part and a deep part.
Origin and insertion
[edit]The muscle's superficial head arises from the distal edge of the flexor retinaculum and the tubercle of the trapezium, the most lateral bone in the distal row of carpal bones.[1] It passes along the radial side of the tendon of the flexor pollicis longus.
The deeper (and medial) head "varies in size and may be absent."[3] It arises from the trapezoid and capitate bones on the floor of the carpal tunnel, as well as the ligaments of the distal carpal row.[3]
Both heads become tendinous and insert together into the radial side of the base of the proximal phalanx of the thumb;[2] at the junction between the tendinous heads there is a sesamoid bone.[4]
Innervation
[edit]The superficial head is usually innervated by the lateral terminal branch of the median nerve.[1] The deep part is often innervated by the deep branch of the ulnar nerve (C8, T1).[2][3]
Blood supply
[edit]The flexor pollicis brevis receives its blood supply from the superficial palmar branches of radial artery.[5]
Action
[edit]The flexor pollicis brevis flexes the thumb at the metacarpophalangeal joint,[1] as well as flexion and medial rotation of the 1st metacarpal bone at the carpometacarpal joint.[3]
Pathology
[edit]Flexor pollicis brevis can, rarely, be completely absent at birth due to a congenital issue (as can the other muscles of the thenar eminence).[6]
Additional images
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The muscles of the left hand. Palmar surface. (Flexor pollicis brevis visible at center right, near thumb.)
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Caput profundum of the Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Bones of the left hand. Volar surface.
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Front of the left forearm. Deep muscles.
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Transverse section across the wrist and digits.
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Superficial palmar nerves.
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Deep palmar nerves.
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Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Flexor pollicis brevis muscle
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Muscles of hand. Cross section.
References
[edit]
- ^ a b c d Fernández-de-las-Peñas, César; Iglesias, Javier González; Gröbli, Christian; Weissmann, Ricky (2012-01-01), Dommerholt, Jan; Fernández-de-las-Peñas, César (eds.), "8 - Deep dry needling of the arm and hand muscles", Trigger Point Dry Needling, Oxford: Churchill Livingstone, pp. 107–118, doi:10.1016/b978-0-7020-4601-8.00008-6, ISBN 978-0-7020-4601-8, retrieved 2020-10-25
- ^ a b c Strickland, James W. (2006-01-01), Henderson, Anne; Pehoski, Charlane (eds.), "Chapter 2 - Anatomy and Kinesiology of the Hand", Hand Function in the Child (Second Edition), Saint Louis: Mosby, pp. 21–44, doi:10.1016/b978-032303186-8.50005-8, ISBN 978-0-323-03186-8, retrieved 2020-10-25
- ^ a b c d Gray's 37th British Edition, p. 630"
- ^ Gray's Anatomy 1918, see infobox
- ^ "Brachium to Hand Musculature". PTCentral. Archived from the original on 4 February 2012.
- ^ Iyer, K. M.; Stanley, J. K. (2017-07-18). "Congenital Absence of Flexor Pollicis Brevis and Abductor Pollicis Brevis". Hand. 14 (3): 313–316. doi:10.1016/S0072-968X(82)80067-3. PMID 7152382. S2CID 41628800.
