The foramen venosum (FV) is an anatomical structure situated at the base of the skull, generally posteromedial to the foramen rotundum and anteromedial to the foramen ovale. Its prevalence and patency may be related to the shape of the skull. The objective of this study was to verify the prevalence and patency of the FV and its association with the different skull types. Overall, 143 dry skulls were screened. Of these, 84 were considered to be in an adequate state of conservation and were included in the analysis, which was conducted through a cross-sectional view of the skullcap. The transverse (T) and anteroposterior (AP) diameters of the skull were evaluated by pachymetry and the skull type was classified according to the cephalic index (CI) (CI = T/ AP x 100). The presence and patency of the FV were evaluated. Overall, 25 % of the skulls were dolichocephalic, 21.4 % sub- dolichocephalic, 26.2 % mesaticephalic, 16.7 % sub-brachycephalic and 10.7 % brachycephalic. Overall, the FV was found in 41.6 % of the skulls (n=35), with this prevalence being greater in the mesaticephalic skulls (50 %; n=11). Patency was 25 % (n=21). A positive correlation was found between the CI and the presence of the FV in dolichocephalic skulls (on the right-hand side only) and in sub-brachycephalic skulls (bilaterally). In conclusion, the prevalence of the FV was considerable in the sample analyzed and was directly associated with the CI in dolichocephalic and sub-brachycephalic skulls.
KEY WORDS: Anatomy; Base of the skull; Craniometry; Foramen venosum.