Question

we have studied in class are involved. In or our purposes, assume that only the four pathways we have studied in class are invol al life, things would not be this simple for a couple of reasons. The injuries rarely wou cact hemisections and secondly other tracts convey some of the sensations assigned to the two acts we studied, and motor control is more than just pyramidal tract function, but also involves -rebellar activity and the "extrapyramidal" tracts that we did not study. Voluntary function ould be lost, but spasticity and reflex function would still exist. me four pathways we have studied include: a) Lateral spinothalamic tract (a sensory pathway conveving pain & temperature sense); b) Dorsal columns (a sensory pathway conveving touch &i, proprioceptive sense c) Lateral corticospinal tract=crossed pyramidal tract), a motor pathway in which roughly 85% of the voluntary motor fibers exist; d) Ventral corticospinal-tract (=direct pyramidal tract), a motor pathway in which roughly 15% of the voluntary motor fibers exist. Dorsal Columns Anterior Corticospinal Corticospinal tract Tract a motor put way motor pathway in n when roughty which roughly ass Wh VOA WA TW 16% of the voluntary of voluntary motor Motor Cres exit fibers exnx Lateral Spinothalamic tract Sensory Pathway Conveyi Dan no temes sense Specific type of information carried 1 Conveying touch And proprio ceptine Level of decussation With a T6 spinal cord hemisection, what deficit would occur in the lower extremities (ipsilateral or contralateral)? 204 Tett pathways Tajor Sensory and Motor Tracts

Answer 1

Dorsal column

Specific type of information carried - Sensory pathway, information carries- fine touch,vibration,two-point discrimination and proprioception

Level of decussation - sensory decussation at medulla .(cross over of gracil nucleus and cuneate nucleus)

Deficit occurs in lower extremities with T6 spinal cord hemisection -Ipsilateral.

Anterior corticospinal tract

Specific type of information carried -Carry movemnt related information from cerebral cortex to spinal cord

Level of decussation- decussate in the spinal level they innevate.

Deficit occurs in lower extremities with T6 spinal cord hemisection- Contralateral

Lateral corticospinal tract

Specific type of information carried-Fine movement of ipsilateral limb.

Level of decussation- Decussate at the pyramid of lower medulla

Deficit occurs in lower extremities with T6 spinal cord hemisection-Ipsilateral

Lateral spinothalamic tract

Specific type of information carried- infromation about crude touch.

Level of decussation- At the level of spinal cord

Deficit occurs in lower extremities with T6 spinal cord hemisection-Ipsilateral