abductor pollicis brevis muscle

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Abductor Pollicis Brevis Muscle

A short flat skeletal muscle that abducts the thumb
Action Moves thumb anteriorly (from anatomic position of the body in space) toward the base of the fifth finger
Nerve Median nerve, recurrent branch
Origin Flexor retinaculum of hand, tubercle of scaphoid bone, and occasionally the tubercle of trapezium
Insertion Lateral base of first phalanx of thumb and capsule of metacarpophalangeal joint
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

ab·duc·tor pol·li·cis brev·is mus·cle

(ab-dŭk'tŏr pol'li-sis brev'is mŭs'ĕl)
Superficial thenar muscle; origin, tubercle of trapezium and flexor retinaculum; insertion, lateral side of proximal phalanx of thumb; action, abducts thumb; nerve supply, median.
Synonym(s): musculus abductor pollicis brevis, short abductor muscle of thumb.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

abductor pollicis brevis muscle

Hand muscle. Origin: flexor retinaculum of wrist, scaphoid and trapezium bones. Insertion: lateral base of proximal phalanx of thumb. Nerve: median (C8-T1). Action: abducts thumb, aides in opposition with digit 5.
See: armfor illus. (Muscles of the Arm)
See also: muscle
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
The CTS group consisted of 546 subjects with clinical symptoms and findings of CTS (e.g., numbness, tingling, paresthesia, pain or sensory deficits in the median nerve distribution, weakness of the abductor pollicis brevis muscle, and a positive Tinel's test) and abnormal nerve conduction studies.
Active electrode was placed over the abductor pollicis brevis, and the reference electrode was placed over the proximal phalanx of the thumb.
The routine work-up is the median nerve motor conduction study with recording from the abductor pollicis brevis (APB) muscle, and median nerve sensory conduction study from the digits II or III to wrist and from palm to wrist segments.
Van Frey's pressure test with Semmes-Weinstein's monofilaments and assessment of Abductor Pollicis Brevis if present.
(17) Grade Nerve Conduction Findings 0 Normal Normal motor and sensory conduction studies 1 Very mild CTS demonstrable only with most sensitive tests 2 Mild Sensory nerve conduction velocity slow on finger/wrist measurement Normal terminal motor latency 3 Moderate Sensory potential preserved Motor slowing; DML to ABP <6.5 ms 4 Severe Sensory potentials absent Motor potential preserved; DML to APB < 6.5 ms 5 Very Severe Sensory potentials absent DML to APB > 6.5 ms 6 Ext Severe Sensory and motor potentials effectively unrecordable Surface motor potential from ABP < 0.2 mV amplitude DSL indicates distal sensory latency; DML, distal motor latency; APB, abductor pollicis brevis; and Ext, extremely.
DLPFC was considered to be located 5 cm anterior to the motor cortex in a parasagittal line, as determined by observing five consecutive contralateral hand muscle (abductor pollicis brevis) contractions.
Physical examination revealed proximal muscle weakness of the upper and lower limbs (muscle test 3/5), and weakness of the distal muscles of both hands, in the abductor pollicis brevis, opponens pollicis, flexor pollicis and the first and second lumbricals particularly.
Median and ulnar nerve motor conduction studies were performed by recording the CMAP from the abductor pollicis brevis (APB) and abductor digiti mini (ADM) muscles respectively with disposable surface electrodes placed in a belly-tendon arrangement.
The atrophy and the weakness of the abductor pollicis brevis and interosseous muscles had also increased.
Thus, carpal tunnel syndrome (CTS) is the entrapment neuropathy of the median nerve that causes paresthesia, pain, numbness, and weakness of the flexor pollicis brevis, opponens pollicis, and abductor pollicis brevis in the innervation area of the median nerve because of its compression in the wrist (1).
Tibial Ankle 0.40 Knee 0.40 22.10 L.: left, R.: right, ms: millisecond, mV: millivolt, m/s: meter/second, APB: abductor pollicis brevis, ADM: abductor digiti minimi, EDB: extensor digitorum brevis, AH: abductor hallucis Table 1b.
Stimulation Points for Median Nerve (Motor): (i) [S.sub.1]--placed at wrist between Palmaris longus and flexor carpi radialis; (ii) [S.sub.2]--placed at elbow crease, medial to biceps tendon; (iii) Ground electrode- dorsum of hand; (iv) Recording electrode- active electrode at the valley of abductor pollicis brevis. (v) Reference electrode- tendon of abductor pollicis brevis.