pyramidal system

a collection of nerve fibres in the central nervous system that extend from the motor cortex in the brain to the spinal cord and are responsible for initiating movement. In the medulla oblongata the fibres form a pyramid (hence the name), within which they cross from one side of the brain to the opposite side of the spinal cord; this is called the decussation of the pyramids. Damage to the pyramidal system manifests in a specific pattern of weakness in the face, arms, and legs, abnormally brisk reflexes, and an extensor plantar reflex (Babinski response).

* * *

tractus pyramidalis (def. 1).

Medical dictionary. 2011.

Look at other dictionaries:

  • pyramidal system — a collection of nerve fibres in the central nervous system that extend from the motor cortex in the brain to the spinal cord and are responsible for initiating movement. In the medulla oblongata the fibres form a pyramid (hence the name), within… …   The new mediacal dictionary

  • Система Пирамидная, Путь Пирамидный (Pyramidal System) — система нервных волокон, по которым произвольные двигательные импульсы от пирамидных клеток, расположенных в коре предцентральной извилины, направляются к двигательным ядрам черепных нервов и передним рогам спинного мозга. Пирамидный путь делится …   Медицинские термины

  • Pyramidal process of palatine bone — Infobox Bone Name = Pyramidal process of palatine bone Latin = processus pyramidalis ossis palatini GraySubject = 41 GrayPage = 168 Caption = Medial wall of left orbit. (Pyramidal process of palatine labeled at bottom right.) Caption2 = Left… …   Wikipedia

  • Pyramidal eminence — Infobox Anatomy Name = PAGENAME Latin = eminentia pyramidalis GraySubject = 230 GrayPage = 1042 Caption = The medial wall and part of the posterior and anterior walls of the right tympanic cavity, lateral view. (Pyramidal eminence labeled at left …   Wikipedia

  • pyramidal — 1. Of the shape of a pyramid. 2. Relating to any anatomical structure called pyramid. * * * py·ram·i·dal pə ram əd əl adj 1) of, relating to, or having the form of a pyramid 2) of, relating to, or affecting an anatomical pyramid esp. of the… …   Medical dictionary

  • pyramidal motor system — noun any of the important motor nerves on each side of the central nervous system that run from the sensorimotor areas of the cortex through the brainstem to motor neurons of the cranial nerve nuclei and the ventral root of the spinal cord • Syn …   Useful english dictionary

  • pyramidal tract — noun any of the important motor nerves on each side of the central nervous system that run from the sensorimotor areas of the cortex through the brainstem to motor neurons of the cranial nerve nuclei and the ventral root of the spinal cord • Syn …   Useful english dictionary

  • system — 1. [TA] A consistent and complex whole made up of correlated and semiindependent parts. A complex of functionally related anatomic structures. 2. The entire organism seen as a complex organization of parts. 3. Any complex of structures… …   Medical dictionary

  • Primate basal ganglia system — The primate basal ganglia system is a symmetrical major cerebral system that has only recently been recognized. In the past, part of it was presented as motor or extrapyramidal , complementary to the corticospinal (pyramidal) system. Contrary to… …   Wikipedia

  • Extrapyramidal system — That part of the nervous system that regulates muscle reflexes. * * * the system of nerve tracts and pathways connecting the cerebral cortex, basal ganglia, thalamus, cerebellum, reticular formation, and spinal neurones in complex circuits not… …   Medical dictionary

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