Corticospinal tract corticospinal upper motor neurons

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Unformatted text preview: psule of tthe forebrain, cerebral peduncle he forebrain, cerebral peduncle att the base of the midbrain, a the base of the midbrain, scatter through the base of the scatter through the base of the pons pons coalesce on the ventral surface coalesce on the ventral surface off the medulla to form the o the medulla to form the medullary pyramids. medullary pyramids. Corticospinal Tract Corticospinal 80 -- 90 % of corticospinal tractt axons cross rticos 80 90 % of corticospinal trac axons cross 90 tto the other side in the distal medulla forming o the other side in the distal medulla forming tthe lateral corticospinal ttract. ract. he lateral cort corticospinal tract. The pyramidal decussation separates the The pyramidal decussation separates the decussation separates medulla,above, ffrom the spinal cord, below. medulla,above from the spinal cord, below. medulla,above, rom The Ventral Corticospinal ttractt contains tthe rac The Ventral Corticos pinal trac contains he Corticos axons from tthe 10-20% off neurons whose ax ons from the 10-20% o neurons whose 20% ax he axons did not cross to the other side at the axons did not cross to the other side at the pyramidal decussation. pyramidal decussation decussation. The upper motor neuron axons tthen synapse The upper motor neuron axons then synapse hen on llower motor neurons iin tthe Anterior horn on ower motor neurons n the Anterior horn he off the spinal cord. o the spinal cord. The axons of tthese lower motor neurons ower The axons of hese llower motor neurons tthen exit the spinal cord via the Ventrall root. hen exit the spinal cord via the Ventra root. Damage to LMN's causes flaccid paralysis. lacc Damage to LMN's causes fflaccid paralysis. LMN's Extrapyramidal Tracts Extrapyramidal Tectospinal ttracts are Tectospinal tracts are racts ffound in cervical cord ound in cervical cord segments only. segments only. begins in the midbrain begins in the midbrain retion called the tectum retion called the tectum tectum axons synapse onto axons synapse onto motor horn cells motor horn ce...
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This note was uploaded on 12/08/2011 for the course AMY 2A taught by Professor Jamesivey during the Spring '06 term at Riverside Community College.

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