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