Systematization, description, and territory of arteries that promote vascularization of the midbrain and rhombencephalon in the ostrich (Struthio camelus)

Abstract

Brain specimens from 30 ostriches were injected with red‐dyed latex via the internal carotid arteries (Aa.). The ventral tectal mesencephalic artery (a.), invariably a medium‐sized single vessel, was, on the right side, a collateral branch of the caudal branch of the carotid artery (53.4%), a direct branch of the carotid artery (43.3%) and a direct branch of the basilar artery (3.3%) and on the left side, a collateral branch of the caudal branch of the carotid artery (66.7%), a direct branch of the carotid artery (30%), and a direct branch of the basilar artery (3.3%). It vascularized only the ventral half of the optic lobe, with no involvement in cerebellar vascularization on the right (93.3%) and left (80%) sides, extending to the ventrorostral‐most cerebellar lobules, which were vascularized on the right (6.7%) and left (20%) sides. The caudal ventral cerebellar arteries were a single vessel on the right (96.7%) and left (93.3%) sides. Its first branch was a common trunk: dorsal spinal—caudal cerebellar on the right (60%) and left (56.6%) sides. Its second branch was the caudal cerebellar artery on the right (76.7%) and left (86.7%) sides. Its third branch was the second component of the caudal cerebellar artery on the right (6.7%) and left (3.3%) sides. The midbrain was vascularized by dorsal and ventral tectal mesencephalic arteries. The cerebellum was vascularized by branches of the caudal ventral cerebellar artery and by the dorsal cerebellar artery.