WordNet

lying away from the median and sagittal plane of a body; "lateral lemniscus"
situated at or extending to the side; "the lateral branches of a tree"; "shot out sidelong boughs"- Tennyson (同)sidelong
a brief treatise on a subject of interest; published in the form of a booklet (同)pamphlet
an extended area of land (同)piece of land, piece of ground, parcel of land, parcel
a system of body parts that together serve some particular purpose

PrepTutorEJDIC

横の,側面の;横からの / (音声が)側音の / 側面,(道路の)側溝(そっこう) / 側音(英語の[1]など)
広大な土地(地域),(土地・海・空などの)広がり《+of+名》 / (器官の)管,(神経の)索
(おもに宗教・政治などの宣伝用の)小冊子,パンフレット

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/12/17 05:33:20」(JST)

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The lateral corticospinal tract (also called the crossed pyramidal tract or lateral cerebrospinal fasciculus) is the largest part of the corticospinal tract. It extends throughout the entire length of the medulla spinalis, and on transverse section appears as an oval area in front of the posterior column and medial to the posterior spinocerebellar tract.

Structure

Descending motor pathways carry motor signals from the brain down the spinal cord and to the target muscle or organ. They typically consist of an upper motor neuron and a lower motor neuron. The lateral corticospinal tract is a descending motor pathway that begins in the cerebral cortex, decussates in the pyramids of the lower medulla ^[1] (also known as the medulla oblongata or the cervicomedullary junction, which is the most posterior division of the brain^[2] ) and proceeds down the contralateral side of the spinal cord. It is the largest part of the corticospinal tract. It extends throughout the entire length of the medulla spinalis, and on transverse section appears as an oval area in front of the posterior column and medial to the posterior spinocerebellar tract.

Function

Axons in the lateral corticospinal tract leave out of the tract and into the anterior horns of the spinal cord. It controls fine movement of ipsilateral limbs (albeit contralateral to the corresponding motor cortex) as it lies distal to the pyramidal decussation. Control of more central axial and girdle muscles comes from the anterior corticospinal tract.^[3]

Damage to different parts of the body will cause deficits, depending on whether the damage is above (rostral) or below (caudal) the pyramidal decussation. Damage to the body above the pyramidal decussation, will cause contralateral motor deficits. For example, if there is a lesion at the pre-central gyrus in the right cerebral cortex, then the left side of the body will be affected. Whereas damage below the pyramidal decussation will result in ipsilateral motor deficits. For example, spinal cord damage on the left side of the lateral corticospinal tract at the thoracic level can cause motor deficits to the left side of the body.

Clinical significance

Poliomyelitis and amyotrophic lateral sclerosis arise out of complications in the lateral corticospinal tract. Both of these diseases result in muscle atrophy. In poliomyelitis, the poliovirus destroys motor neurons found in the brainstem and anterior horn of the spinal cord. This inhibits the lower motor neurons of the lateral corticospinal tract from travelling to the target muscle or organ and delivering the signal from the brain. In amyotrophic lateral sclerosis, the lateral side of the spinal cord undergoes scarring. The astrocytes found in the spinal cord, which are vital to the healthy functioning of the central nervous system, fail to reabsorb a specific neurotransmitter. This causes the neurotransmitter to reach toxic levels and leads to scarring in the lateral regions of the spinal cord. This also disrupts neural signal transmission.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

^ Saladin, Kenneth (2012). Anatomy and Physiology: The Unity of Form and Function. New York: McGraw-Hill. pp. 486–488. ISBN 978-0-07-337825-1.
^ Pinel, John (2011). Biopsychology. Boston: Pearson Education Inc. ISBN 978-0-205-83256-9.
^ Blumenfeld, Neuroanatomy Through Clinical Cases, 2002

Additional images

Decussation of pyramids.
Section of the medulla oblongata through the lower part of the decussation of the pyramids
Section of the medulla oblongata at the level of the decussation of the pyramids.
The motor tract.

External links

hier-798 at NeuroNames
-845545463 at GPnotebook
Overview at thebrain.mcgill.ca
Illustration and text: sc97/text/P4/intro.htm at the University of Wisconsin-Madison Medical school

UpToDate Contents

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English Journal

Restoration of locomotion in paraplegics with aid of autologous bypass grafts for direct neurotisation of muscles by upper motor neurons--the future: surgery of the spinal cord?

von Wild KR1, Brunelli GA.
Acta neurochirurgica. Supplement.Acta Neurochir Suppl.2003;87:107-12.
OBJECTIVES: Paraplegia means a lifelong sentence of sensory loss, paralysis and dependence. Complete spinal cord lesions cannot heal up to now despite intensive experimental research, remarkable efforts and recent achievements in bio-technology and re-engineering. Traumatic paraplegia due to spinal
PMID 14518535

An observation on hitherto unknown corticospinal fibers that descend between the tractus corticospinalis lateralis and ventralis in the cat.

Satomi H1, Takahashi K, Mizuguchi A, Aoki M.
Neuroscience letters.Neurosci Lett.1991 Aug 19;129(2):168-72.
Following injection of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP) into the pericruciate (sensorimotor) cortex on one side in the cat, we found labeled fibers surrounding the ventral horn of the spinal cord bilaterally, in addition to the crossed and the uncrossed lateral, vent
PMID 1720875

Japanese Journal

On Motor and Sensory Nerve Systems in in Lumber Cord in Man

The Tohoku Journal of Experimental Medicine 59(1-2), 37-51, 1953
NAID 130003496562

「錐体側索路」

Lateral corticospinal tract
	Lateral corticospinal tract labeled in red at upper left.
Details
Identifiers
Latin	Tractus corticospinalis lateralis,; fasciculus cerebrospinalis lateralis
TA	A14.1.02.219
FMA	72635
	Anatomical terminology [edit on Wikidata]