BackgroundGranular foveolae in the groove of the sigmoid sinus have rarely been reported in the literature compared to numerous published reports on the granular foveolae near the superior sagittal sinus and its sulcus on the internal aspect of the calvaria. The present study was performed to better elucidate their prevalence and locations. Materials and methodsOne hundred and ten adult dry skulls (220 sides) were analyzed for the presence of granular foveolae within the groove of the sigmoid sinus. The exact position of the foveolae was documented, and the diameter of the granular foveola was measured. ResultsGranular foveolae were found in the groove of the sigmoid sinus on 3.6% of the sides. These were at or within a mean of 1.3 cm inferior to the transverse-sigmoid junction. When a mastoid foramen was noted in the groove, it was always located inferior to the granular foveolae when present. The mean diameters of the granular foveolae of the left groove of the sigmoid sinus were 2.8 mm and 4 mm for the right grooves. The mean depth of the granular foveolae in the left groove of the sigmoid sinus was 2.7 mm and 3.5 mm for the right grooves. Granular foveolae were statistically larger and deeper on the right versus left sides (p<0.05). ConclusionsGranular foveolae of the groove of the sigmoid sinus were identified most commonly on the right sides and 3.6% on all sides. If identified on medical imaging, these uncommon structures at the skull base should be considered normal anatomical variations.

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Granular foveolae in the groove of the sigmoid sinus have rarely been reported in the literature compared to numerous published reports on the granular foveolae near the superior sagittal sinus and its sulcus on the internal aspect of the calvaria. The present study was performed to better elucidate their prevalence and locations. One hundred and ten adult dry skulls (220 sides) were analyzed for the presence of granular foveolae within the groove of the sigmoid sinus. The exact position of the foveolae was documented and the diameter of the granular foveola were measured. Granular foveolae were found in the groove of the sigmoid sinus on 3.6% of sides. These were at or within a mean of 1.3 cm inferior to the transverse-sigmoid junction. When a mastoid foramen was noted in the groove, it was always located more inferior to the granular foveolae when present. The mean diameters of the granular foveolae of the left groove of the sigmoid sinus was 2.8 mm and 4 mm for right grooves. The mean depth of the granular foveolae of the left groove of the sigmoid sinus was 2.7 mm and 3.5 mm for right grooves. Granular foveolae were statistically larger and deeper on right versus left sides (p < 0.05). Granular foveolae of the groove of the sigmoid sinus were identified most commonly on right sides and on 3.6% of all sides. If identified on medical imaging, these uncommon structures at the skull base should be considered normal anatomical variations.

BackgroundThe atrioventricular (AV) node is a relay station for electrical signals passing between the atria and ventricles. The artery supplying the AV node is functionally important, and its anatomical topography is relevant during invasive procedures. Therefore, the aim of this study was to identify and understand the variations of the origin of the AV nodal branch (AVNb) and its variations. Materials and methodsWe dissected 31 adult human hearts to evaluate their AVNb and its variations. A classification scheme was used to detail the morphology found for each of these arteries. ResultsWe identified five distinct origins of the AVNb: AVNb originating from the right coronary artery (RCA) proximal to the inferior interventricular branch (IVb) (type I, 3.2%), AVNb originating from the junction of the RCA and IVb (type II, 19.4%), AVNb originating from the RCA distal to the IVb (type III, 64.5%), AVNb originating from the IVb (type IV, 6.5%), and AVNb originating from the circumflex branch of the left coronary artery (LCA) (type V, 6.5%). ConclusionsOur study provides data on the morphology and variations of the AVNb. Such information can assist in better diagnoses based on imaging, better guide invasive procedures, and provide the cardiac surgeon with an improved method of classifying the AVNb and its branches during procedures of the coronary arteries and their branches.