Parietal foramen as a landmark to locate intracranial vascular and parenchymal structures

Abstract

Objective
This study aimed to define the location of the parietal foramina (PF) in relation to skull landmarks and correlate the PF with cerebral and vascular structures to optimize neurosurgical procedures within the intracranial compartment.
Methods
Two hundred thirty-eight parietal bones, studied using magnetic resonance imaging (MRI) in 119 patients, were reviewed. The cephalometric points, including inion, bregma, sagittal suture, and lambda, were used as anatomical references to locate the PF and define its anatomical relationships to parenchymal cerebral structures, particularly some eloquent areas.
Results
The PF was identified in the MRI in 83 of the 119 individuals (69.7%) and was located at a distance of 9.5 ± 0.8 cm (mean ± SD) posteriorly and 0.9 ± 0.3 cm laterally to the bregma. In over 90% of cases, the PF was located within a 2 cm radius of the mean value of the bregma-PF distance. 88% of the 62 left PFs were situated within 1 cm, laterally to the left margin of the superior sagittal sinus (SSS). 60% of the right PF were located within 1.3 cm laterally from the right margin of the SSS, while 40% were directly above the SSS.
Conclusion
The PF should be considered a reliable reference point for the SSS during its course through the parietal lobe, as its consistency surpasses that of other commonly used landmarks, such as the sagittal suture and midline. Identified in approximately 70% of individuals, the PF demonstrates a relatively constant anatomical relationship with the SSS. Recognizing this foramen is crucial for neurosurgeons operating in the parietal region, not only to avoid iatrogenic injury to the emissary veins, arteries, and nerves that traverse it—which could lead to complications such as air embolism—but also to provide a more dependable guide for navigating the SSS. Surgeons should remain aware of the PF’s frequency (69.7%), its typical location superolateral to the lambda, and its stable topographic association with underlying structures.