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

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.

Systematization, Description, and Territory of the Middle Cerebral, Rostral, and Cerebroethmoidal Arteries on the Surface of the Brain of the Ostrich (Struthio camelus).

Thirty ostrich specimens were injected with red-dyed latex via the internal carotid arteries (Aa.) The middle cerebral and cerebroethmoidal arteries and their branches were systematized. The middle cerebral artery (a.) was always a single large vessel. On the right side, it had two, three, or one developed medial hemispheric branches in 46.6%, 26.7%, and 26.7% of cases, respectively. On the left side, one (36.7%), two (33.3%), and three (30%) developed medial hemispheric branches were observed. The middle cerebral artery had eight (40%), nine (20%), seven (16.7%), eleven (6.7%) ten (6.7%), twelve (3.3%), six (3.3%), and five (3.3%) developed lateral hemispheric branches on the right side and seven (46.7%), nine (13.3%), eight (13.3%), six (10%), five (10%), and ten (6.7%) on the left. Two (33.3%), four (20%), three (20%), one (16.7%), and five (10%) direct perforating branches of the middle cerebral artery were present on the right, and three (33.3%), two (30%), one (13.4%), six (10%), four (10%), and five (3.3%) were present on the left. The cerebroethmoidal artery, always present as a natural continuation of the rostral terminal branch of the brain's carotid artery and originating from the middle cerebral artery, was a large vessel that projected rostromedially, giving off the rostral cerebral artery shortly after its formation and continuing as the ethmoidal artery. The rostral cerebral artery was a single (90%) and double (10%) vessel on the right and a single (96.7%) and double vessel (3.3%) on the left. The ethmoidal artery was always a medium to large single vessel and was the natural continuation of the cerebroethmoidal artery, immediately after giving off the rostral cerebral artery. Anat Rec, 302:1187-1194, 2019. © 2018 Wiley Periodicals, Inc.