Morfometria dos forames emissários parietais: prevalência e variações relacionadas ao sexo

Parietal emissary foramens are structures located in the parietal bones, through which vessels, called emissary veins, that help in intracranial drainage travel and have great advantages, as a place for surgical access; act by equalizing and regulating intracranial pressure; act on brain temperature regulation and function as safety valves during brain congestion. The objective of this study was to perform a morphological analysis of the parietal emissaries, evidencing their prevalence and variations with regard to the sexes. The foramina were analyzed for their shape, location and size; the analyzes were carried out in skulls of the Collection of the Human Bone Collection of the Academic Center of Vitoria. The parietal foramina was encountered in 75 of the 89 (84.3%) studied dry skulls [32/38 (84.2%) in women versus 43/51 (84.3%) in men, p>0.05]. The parietal foramen was present bilaterally in 44.73% of females and 54.9% of males. A slight asymmetry was encountered between sides regarding unilaterality, the right parietal bone with 21% versus 18% (left) in females and 16% versus 14% (left) in males (p>0.05). The accessory parietal foramen was present in the right parietal in 2.6% and in 7.9% on the left side of the females, while 5.9% and 3.9% of the males presented an accessory parietal foramen on the right or left sides, respectively. In all hemicrania with a parietal foramen examined, the parietal foramina located in the posterior part of the parietal bone (male 84 ± 8 mm from bregma and 33 ± 8 mm from lambda; female 84 ± 6 mm from bregma, 30 ± 6 mm from lambda), in the proximity of the sagittal suture [male 7.1 ± 2.5 (min 1.9 - max 13.4) mm versus female, 7.4 ± 2.7 (min 2.2 - max 13.2) mm; Figure 2]. There was a positive correlation (p=0.0002, linear regression) between the right and left parietal foramina regarding the distance from midline. The distance from a foramen to the contralateral one was 16 ± 4 mm in men and 18 ± 5 mm in women, respectively (p>0.05). No statistical differences were found between sexes in the distance between the foramen and the ipsilateral eurion either on the right or on the left. There were no statistically significant differences when comparing the distance between the right and left foramina, in men and women. The external appearance of the parietal foramina (n=120, with the exception of the accessory parietal foramina) was a round shape in all except 4 foramina which the contour was oval. The results brought about by this research are of great interest to neurologists, neurosurgeons and radiologists, since they are structures that are involved in a series of particularities, such as being a place for surgical access, acting in the regulation of pressure and temperature intracranial.