Systematization, Distribution and Territory of the Middle Cerebral Artery on the Brain Surface in Chinchilla (Chinchilla lanigera)

Morphometry and Variability of the Brain Arterial Circle in Chinchilla (Chinchilla laniger, Molina)

Arterial circles of brains from 70 adult chinchillas were filled with synthetic latex. The arterial circle of the brain is formed as the result of vertebral arteries being merged into the basilar artery. Caudally, both vertebral arteries gave rise to the ventral spinal artery. The ventral spinal artery splits into tiny cerebellar vessels, the pontine and cochlear branches. Distally, the basilar artery ramified into two terminal branches that formed the arterial circle of brain, rostrally open in most cases (75%). The observed variability of the arterial circle of brain of chinchillas pertained to all elements of that circle. The greatest variability within the vessels of the circle of Willis in chinchillas was observed in 22 cases (31.4%) of internal ophthalmic arteries. In chinchillas, a trend toward slight variability within the arteries comprising the arterial circle of the brain was observed in 44 animals. This accounted for 62.8% of all cases. Only in three cases was the arterial circle of brain clearly symmetrical. At the same time, 23 animals (32.8%) revealed features of significant vascular variability within the brain base region. These consisted of disturbed geometry of the entire arterial circle, different levels of ramifications into individual arteries, as well as the number and diameter of arteries. No internal carotid arteries were observed in chinchillas apart from one atypical case in which the carotid artery extended unilaterally into the basilar artery. These investigations indicate on the significant variability of arterial circle in rodents. Anat Rec, 300:1472-1480, 2017. © 2017 Wiley Periodicals, Inc.

A systematic study of the brain base arteries in the rabbit (Oryctolagus cuniculus)

The brains of 30 New Zealand rabbits (Oryctolagus cuniculus) were injected with red stained latex. The arteries of the ventral surface of the brain were systematized on the right (R) and on the left (L) side with the respective percentage of appearance: the aortic arch emitted the braquicephalic trunk and the left subclavian artery (83.3%); or the braquicephalic trunk, the left common carotid artery and the left subclavian artery (16.7%). The braquicephalic trunk emitted the right and the left common carotid arteries and the right subclavian artery (83.3%); or the right common carotid artery and the right subclavian artery (16.7%). The common carotid arteries were divided into external and internal carotid arteries (96.7% on the R, 100% on the L.). The internal carotid artery to the R was present (96.7%) and absent (3.3%), and to the L, was present (100%). The rostral choroidal artery to the R was collateral branch of the rostral branch of the internal carotid artery (83.3%), collateral branch of caudal branch of the internal carotid artery (16.7%), and to the L was collateral branch of the rostral branch of the internal carotid artery (93.3%), collateral branch of the caudal branch of the internal carotid artery (6.7%). The middle cerebral artery to the R and to the L was single (80%) and double (20%). The rostral cerebral artery to the R had middle caliber (90%), thin caliber (6.7%) and too thin caliber (3.3%), and to the L had middle caliber (76.7%), thin caliber (16.7%) and too thin caliber (6.7%). The internal ethmoidal artery was absent (73.3%), present and single (26.7%). The caudal cerebral artery to the R was single (66.7%), double (26.7%) and triple (6.7%), and to the L was single (63.3%) and double (36.7%). The terminal branches of the right and left vertebral arteries were present (100%, and formed the basilar artery (100%). The ventral spinal artery was present (100%). The caudal cerebellar artery, to the R was single (43.3%), single with labyrinthic artery isolated (26.7%) and double (30%), and to the L was single (50%), single with labyrinthic artery isolated (6.7%), double (40%) and triple (3.3%). The trigeminal artery to the R and to the L was present (100%). The rostral cerebellar artery to the R was single (53.3%) and double (46,7%), and to the L was single (63.3%) and double (36.7%). The rabbit's cerebral arterial circle was caudally closed (100%) and rostrally closed (93.3%) or opened (6.7%). The brain was supplied by the vertebral-basilar and carotid systems.