Tract Site of Origin Site of Decussation Levels Of
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Transcript of Tract Site of Origin Site of Decussation Levels Of
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TractSite of Origin Function
ateral Motor Systems
ateral Corticospinal Tract
Rubrospinal Tract
Cervical cord
edial Motor Systems
Anterior cortiospinal tract
teral Vestibulospinal Tra
entire cord
none
Site of decussation(crossing over)
Levels of Termination
Primary motor cortex - B4
(33%)premotor cortex - B6
(33%),somatosensory cortex -
B3,1,2 (33%)
Pyramidal decussation at
the cervicomedullaryjunction (medulla/SC)(90% of fibers cross)
Entire Cord -
predominately at cervicaland lubosacralenlargements
Movement of Contrala
Limbs - rapid, dextrouat individual digits or j(voluntary, skilled mvm
Lesion ABOVEpyramidal dec= contraweakness/LesionBELOW=Ipsilateral we
Red nucleus,magnocellular division
red nuc receives inputfrom cerebral cortex andcerebellar nuclei
Ventral tegmentaldecussation -midbrain
Movement of contralatlimbs (function uncert
humans) excitesneurons innervating flmm in proximal limb
Primary motor cortexand..
Tract runs to terminalLMN ipsilaterally and alsocrosses thru the ventralwhite commissure to thecontralateral side at thesame level. = bilateraleffects
cervical and upperthoracic cord
Control of bilateral axigirdle muscles
lateral vestibular nucleus(pons)
none - projectsipsilaterally only
maintain upright postbalance by exciting ex
of mainly the legs
medial vestibular nucleus cervical and uppper 1.) adjusts head posit
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ppp j p
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