Flexor pollicis brevis muscle

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Flexor pollicis brevis muscle
Musculusflexorpollicisbrevis.png
The muscles of the left hand. Palmar surface. (Flexor pollicis brevis visible at center right, near thumb.)
Latin musculus flexor pollicis brevis
Gray's p.461
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
TA A04.6.02.055
FMA 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. It has both a superficial part and a deep part.

Origin and insertion[edit]

The muscle's superficial part arises from the distal edge of the flexor retinaculum and the tubercle of the trapezium, a bone in the wrist. It passes along the radial side of the tendon of the flexor pollicis longus, and, becoming tendinous, is inserted into the radial side of the base of the proximal phalanx of the thumb; in its tendon of insertion there is a sesamoid bone.[1]

The deeper (and medial) portion of the muscle is very small, and arises from the ulnar side of the first metacarpal bone between the oblique part of the adductor pollicis and the lateral head of the first dorsal interosseous muscle, and is inserted into the ulnar side of the base of the first phalanx with the adductor pollicis.[1]

The deep (medial) part of the flexor brevis pollicis is sometimes described as the first palmar interosseous muscle.[1] When this muscle is included, the total number of palmar interossei is four. Otherwise, there are only three palmar interossei.

Innervation[edit]

The flexor pollicis brevis is mostly innervated by the recurrent branch of the median nerve (C8, T1). The deep part is often innervated by the deep branch of the ulnar nerve.[2][3]

Blood Supply[edit]

The flexor pollicis brevis receives its blood supply from the superficial palmar branches of radial artery.[3]

Action[edit]

The flexor pollicis brevis flexes the thumb at the metacarpophalangeal joint.[2]

Additional images[edit]

Flexor pollicis brevis muscle 
Bones of the left hand. Volar surface. 
Front of the left forearm. Deep muscles. 
Transverse section across the wrist and digits. 
Superficial palmar nerves. 
Deep palmar nerves. 
Flexor pollicis brevis muscle 
Flexor pollicis brevis muscle 
Flexor pollicis brevis muscle 
Flexor pollicis brevis muscle 
Flexor pollicis brevis muscle 
Flexor pollicis brevis muscle 
Flexor pollicis brevis muscle 
Flexor pollicis brevis muscle 
Flexor pollicis brevis muscle 
Flexor pollicis brevis muscle 
Muscles of hand. Cross section. 

References[edit]

  1. ^ a b c Gray's Anatomy 1918, see infobox
  2. ^ a b Origin, insertion and nerve supply of the muscle at Loyola University Chicago Stritch School of Medicine
  3. ^ a b "Brachium to Hand Musculature". PTCentral. Retrieved November 2012. 

This article incorporates text from a public domain edition of Gray's Anatomy.