POSTURAL REFLEXES

From Big Medical Encyclopedia

POSTURAL REFLEXES (Latin positura situation; a reflex) — the reflexes providing steady saving the provision of a body or its parts (the head, a trunk, extremities) both in space, and on the relation to each other. Items of river provide preservation poses (see), than they differ from motive reflexes.

The origins of P. of river are difficult. The afferent irritations causing P. of river proceed from proprioceptors of muscles and receptors of a labyrinth. The central mechanisms P. of river include the spinal level and supraspinal systems influencing on and - and at - motor-neurons of a spinal cord. In P.'s implementation by the river the most significant role is played by systems of lateral and medial preddverno-spinal ways, a medial longitudinal bunch, krasnoyaderno-spinal and reticular and spinal ways, and from cellular educations — a reticular formation oblong and a mesencephalon, a medial vestibular nucleus, a lateral vestibular nucleus (Deyters's kernel), the red kernel, black substance, basal kernels and some other kernels of a brain trunk providing static and statokinetic reactions (see). At the person P. is normal rubles clearly are expressed only in the first months of life. With age they considerably are suppressed with activity of the cerebral cortex regulating any pose.

Experimentally on the decerebrated animals with section of esodic nerves it is possible to receive special P. of river, or so-called ukorotitelny and lengthening reactions: the muscle as if stiffens in a condition of shortening or lengthening, and an extremity respectively in a condition of extension or bending. The mechanism P. of river in this case, apparently, is connected with disturbance of regulation adjusting reactions (see), providing automatic return of an extremity to a normal pose at its change.

Diagnostic value the rubles fixing a condition of shortening or lengthening of a muscle at some point have so-called elementary, or local, P. The-foot phenomenon (Vestfal's phenomenon) and a phenomenon of a shin concern to them (a phenomenon of Fua — Tevenara). -Foot phenomenon: if to make extension of foot, then it stiffens in this situation while normal it automatically is returned to the initial position. Phenomenon of a shin: if at the patient lying on a stomach to bend a shin in a knee joint and to hold its nek-swarm time in the provision of extreme bending, then then it after insignificant independent extension stiffens in the bent situation and does not give vigorous extensive return as it is usually observed normal. Sometimes the-foot phenomenon and a phenomenon of a shin apply to definition of fixating rigidity. Both of these phenomena usually note in combination with the raised muscle tone of plastic or wax-like character and other symptoms what indicates defeat extrapyramidal system (see).

See also Magnus — Klein reflexes , Myostatics , Reflex .


Bibliography: Badalyan L. O. Children's neurology, page 52, M., 1975; Batuyev A. S. both Tairov O. P. Mozg and organization of movements, L., 1978; Bogolepov N. K., etc. Nervous diseases, page 144, M., 1956; Granite P. Bases of regulation of movements, the lane with English, M., 1973; M. B. and Fedorov E. A. Crawl. Main neuropathological syndromes, M., 1966; Magnus R. Installation of a body, the lane with English, page 624, M. — L., 1962; Semenova K. A. Cerebral palsies, M., 1968; Sherry of N of of t about Ch. S N. Integrative activity of a nervous system, the lane with English, JT., 1969; S t e j s k and 1 L. Postural reflexes in theory and motor re-education, Praha, 1972.


L. A. Kukuyev.

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