Morphometric Analysis of Foramina in the Middle Cranial Fossa of Dogs: A Retrospective Cone-Beam CT Study

Although extensively studied in humans, data on the middle cranial fossa foramina remain limited in dogs, despite their different skull morphology and high relevance to veterinary neurology, surgery and oncology. In this retrospective anatomic study, we aimed to fill this gap by presenting the morphometric data of these foramina in domestic dogs of different breeds, ages, body weights, and skull sizes. The study used CBCT images of 40 dogs. Dogs were divided into three groups (small, medium, and large), regardless of sex, body weight, and breed, using neurocranium length. Then, morphological and morphometric analyses of the foramina were performed. The neurocranium length of each group differed significantly from the others (p < 0.001). In each group, the orbital fissure and round and oval foramina were bilaterally located rostrally to caudally and were of similar size (p > 0.05). While the orbital fissure was a canal in 80% of dogs, in dogs with medium and large skull sizes (17.5%), the spinous foramen showed variation, becoming both a foramen and a canal. The opening sizes increased along with the skull size (p < 0.001); the widest opening was the orbital fissure, and the narrowest opening (except for the spinous foramen) was the oval foramen. The findings may guide skull base surgeries, regional anesthesia, and the diagnosis of cranial nerve dysfunctions. Furthermore, a classification based on neurocranial length is anticipated to provide more objective craniometric measurements in animals with diverse head types and body weights.