Brain stem arteries in canis familiaris - Implications in experimental procedures

Canis familiaris is widely used as an experimental model, namely in the study of vascular lesions in the region of the vertebro-basilar arterial system. Although there are some works published on the normal pattern of the arteries that supply the brain stem in this species, most studies were obtained from relatively small series, and scant information exists regarding the variations of the arteries of this region. To contribute to a better understanding of brain stem arteries in dog, we injected coloured latex in 25 adult mongrel dogs. The brain stems were removed and their superficial vessels carefully analysed under a stereotaxic microscope. Then, the brainstems were cut in 2 mm thick slices, and turned diaphanous, which allowed the study of their perforating arteries. All the arteries to the brainstem derived from the vertebral, basilar and caudal communicating arteries. Variations were found in the number of pontine arteries, in the different extent to which perforating arteries penetrated in the different portions of the brainstem, and in the morphology of the basilar artery. Overall, the general pattern of vascularisation is similar in dogs and in humans, with the important exceptions of the origin of the caudal cerebral artery and the rostral cerebellar artery, and the relatively larger contribution of the vertebro-basilar system to the brain blood supply in Canis familiaris. We conclude that, from an anatomical standpoint alone, the dog seems to be an adequate model for experimental procedures involving the arteries that supply the brainstem.