Morphological Variations in the Transverse Venous Sinus Anatomy of Dogs and its Relationship to Skull Landmarks

Abstract

We characterized the anatomical morphology of the transverse venous sinus (TVS) of 69 canine adult cadavers belonging to three groups: brachycephalic (B), dolichocephalic (D) and mesaticephalic (M). In addition, we outlined its path over the skull using five classic human craniometric points (CPs): the asterion (ast), the bregma (b), the glabella (g), the stephanion (st) and the pterion (pt). The study aimed to establish anatomical differences in the TVS between groups and in the relationship between the TVS and skull. We found that TVS anatomy and its relationships to skull landmarks vary markedly between the groups, with similar anatomical arrangements in B and M. The TVS length can be ranked as M < B < D (with D being the biggest), whereas the width can be ranked as M < D < B (with B being the widest) with the right side being smaller than the left. In the B and M groups, the TVS assumes a craniocaudal trajectory that is closer to the lateral skull wall than in D, where the TVS presents a caudocranial direction. By documenting the morphological characteristics of the TVS, we can create a set of anatomical references allowing construction of a basic framework to greatly decrease the probability of TVS injury during neuronavigation procedures when supported by a good knowledge of the skull, brain anatomies and their relationships.

Canine Intracranial Venous System: A Review

“…Since the intracranial veins have no valves, they are able to develop alternative channels, e. g. in the case of their obstruction [42,43,49]. Generally, there are two main systems providing for venous outflow from the canine cerebrum-a dorsal and ventral one [12,15,19,23,39].…”

“…However, the StS also can enter the occipital bone via an accessory foramen and merge separately with the CoSs [3,13,15,19,39,41]. [3,12,31,49].…”

“…The variations in size and shape of the cranium in different breeds of Canis lupus familiaris (e. g. in brachycephalic, mesocephalic, or dolichocephalic dogs) principally influence neither the elementary morphology nor function of the ICVS [14,15].…”

“…In comparison with the arterial compartment, the venous one contains about 70-80 % of the circulatory volume inside the skull [12,16,34,43,49]. Detailed knowledge of: the morphology, composition, and function of DVSs, their tributaries, important connecting veins, and potential occurrence of their anomalies is essential for neurological diagnostics, assessment of therapeutic options, and the success of neurosurgical interventions in both, human as well as in veterinary health care practice [1,3,7,12,15,26,32,39,49]. Since traumatic events as well as different pathological processes involving the skull, meninges, brain, vertebral column, and spinal cord in humans, also occur in big mammals, the structure and function of their ICVSs are similar; the porcine, canine, ovine, and feline models are often used in experimental and clinical neuroscience for translational research [10, 13, 14, 22, 24, 26, 28, 30, 34, 35, 37, 47, 51, 53-56, 58, 59].…”