Anatomic Variations of the Perineal Arteries and Nerves in the Male and Female Dog and Its Clinical Implications

SIMPLE SUMMARY: The study of perineal arteries and nerve distribution in dogs has shown that there are several anatomical variations that may be encountered in clinical practice, highlighting the importance of understanding the blood supply and innervation of the perineal region. There is a description of the perineal arteries to be used as a reference, in which the dorsal perineal artery is shorter and only vascularises the dorsal part of the perineum. Whereas in the vascular variations described in this study, the long-type perineal artery and the perineal trunk passed distally beyond the point of origin of the ventral perineal artery. The classic pattern of perineal artery distribution was observed in only 46% of the specimens with most of the remaining cases showing either a dorsal perineal artery “long type” or a perineal trunk variation. The perineal nerve was found to always follow the route of the dorsal perineal artery “long type” and perineal trunk but not when presented in the traditionally described vascular pattern. These findings are important for anatomists, surgeons, and anatomy teachers and students. For the latter, it is an added value, as it is important for them to understand how different anatomical regions can be from anatomy books. ABSTRACT: The anatomic variations of the perineal arteries and nerves are studied in the dog. The aim of the study is to provide a more detailed understanding of the blood supply and innervation of the perineal region, providing detailed information on the perineal arteries and nerve distribution and their variability in male and female dogs. The study used 232 pelvic halves from 116 adult dogs and analysed the differences using the chi-squared test. The results showed that the presumptive model for perineal artery distribution described in N.A.V. was observed in 46% of the specimens. Additionally, a dorsal perineal artery “long type” was found in 13% of the dogs, and a perineal trunk was present in 41% of the dogs. In the study, there was no variation in perineal nerve distribution, and it was found that the perineal nerve did not run together with the dorsal perineal artery when it was the “short type” as described in the presumptive model for perineal artery distribution. Instead, it always followed the route of the dorsal perineal artery “long type” and the perineal trunk when they were present. The findings of the study may be useful for veterinary surgeons when approaching the perineal region in dogs.