Corticospinal tract – corticobulbar tracts

1. Corticospinal tract – corticobulbar tracts Cerebral cortex Figure 22. Corticospinal and corticobulbar pathways. Corticospinal fibers in posterior limb of internal capsule Internal capsule Corticobulbar fibers to control face motions are in genu of internal capsule Superior colliculus Red nucleus Midbrain – cerebral peduncle Corticobulbar fibers – ipsilateral to red nucleus and superior colliculus Corticospinal tract runs through ventral pons Corticobulbar fibers – ipsilateral to pontine nucleus, contralateral to part of facial nucleus controlling lower face Basal pons Corticobulbar fibers bilateral to most other cranial nerve nuclei and reticular formation Medullary pyramid Pyramidal decussation at cervicomedullary junction (~90% of fibers cross) Anterior (ventral) corticospinal tract descends in the ipsilateral anterior funiculus and terminates in medial part of ventral horn (goes to axial motor neurons) Lateral corticospinal tract descends in the contralateral lateral funiculus and terminates in gray matter