basal joint reflex

ba·sal joint re·flex

opposition and adduction of the thumb with flexion at its metacarpophalangeal joint and extension at its interphalangeal joint, when firm passive flexion of the third, fourth, or fifth finger is made; the reflex is normally present but absent in pyramidal lesions.
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basal joint reflex

n.
A reflex of the thumb in which the metacarpophalangeal joint flexes and the interphalangeal joint extends in response to firm passive flexion of the third, fourth, or fifth finger.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

ba·sal joint re·flex

(bā'săl joynt rē'fleks)
Opposition and adduction of the thumb with flexion at its metacarpophalangeal joint and extension at its interphalangeal joint, when firm passive flexion of the third, fourth, or fifth finger is made; the reflex is present normally but is absent in pyramidal lesions.
Synonym(s): finger-thumb reflex, Mayer reflex.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

Mayer,

Karl, Austrian neurologist, 1862-1932.
Mayer reflex - apposition and adduction of the thumb. Synonym(s): basal joint reflex
Medical Eponyms © Farlex 2012