Whereas at a level above the medulla a lesion occurring in one hemisphere would mean that the other hemisphere could still sufficiently innervate the posterior facial motor nucleus, a lesion affecting a lower motor neuron would eliminate innervation altogether because the nerves no longer have a means to receive compensatory contralateral input at a downstream decussation.
32.
Cortical upper motor neurons originate from Brodmann areas 1, 2, 3, 4, and 6 and then descend in the posterior limb of the internal capsule, through the crus cerebri, down through the pons, and to the medullary pyramids, where about 90 % of the axons cross to the contralateral side at the decussation of the pyramids.
33.
Occupying the posterior part of the commissure of the optic chiasma is a strand of fibers, the "'Ventral supraoptic decussation "'( "'commissure of Gudden "', "'Gudden's inferior commissure "'), which is not derived from the optic nerves; it forms a connecting link between the medial geniculate bodies.
34.
Therefore, a lesion that is caudal to the sensory decussation where the remaining 3 / 5 modalities decussate ( at the superior medulla ) will result in contralateral ( opposite sided ) pain and temperature loss ( as this has already crossed over at the anterior white commissure ), whereas loss of crude touch, pressure, and proprioception will be ipsilateral ( same sided ) as these have not yet crossed over.
How to say decussation in Hindi and what is the meaning of decussation in Hindi? decussation Hindi meaning, translation, pronunciation, synonyms and example sentences are provided by Hindlish.com.
