spinal tracts

[mrslackalot]

studying for the neuro exam, but my textbooks are awful. got a quick question: the corticospinal tract decussates at the bottom of medulla oblangata, while the medial lemnicus pathway decussates at the medulla-cervical junction, so damage somewhere in between on the right side would produce ipsilateral motor deficits and contralateral sensory decifits. am i correct? also, what effect will the fact that anterior corticospinal tract doesn't decussate have in this clinical scenario? please feel free to add nuances.

thanks a lot!!

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[danielmd06]

It's been awhile but I'll do my best here...

(1) The anterior corticospinal tracts are of uncertain clinical significance, and would play no role in your example.

(2) A lesion in the corticospinal tracts in the R medulla above the pyramidal decussation would result in L-sided (contralateral) hemiparesis or hemiplegia. A lesion inferior to the pyramidal decussation would give you ipsilateral hemiparesis.

(3) A lesion in the posterior column medial lemniscal pathway in the R medulla inferior to the sensory decussation would give you R-sided (ipsilateral) loss of proprioceptive, vibration, and fine touch modalities.

(4) The vascular territory would be derived from the vertebrobasilar system.