Anatomical Study of Parietal Emissary Foramina in Human Skulls

Abstract

Introduction: Emissary veins connect the intracranial venous sinuses with the veins outside the cranium. The foramina of the skull through which they traverse are known as emissary foramina. The emissary veins are valve less, so, blood can flow bidirectionally and serve an important function of equalizing intracranial pressure and can act as safety valves during cerebral congestion. Aim: To find out the frequency of occurrence of the parietal emissary foramina in adult South Indian skulls and their topographical location with reference to the sagittal suture and the lambda. Materials and Methods: A collection of 78 adult skulls of unknown sex were examined for the occurrence of parietal emissary foramina. The size of the foramina was measured with a digital caliper. Distances between the foramen and the sagittal suture and the lambda were also measured with a digital caliper. Results: The parietal emissary foramina were absent in 69 (44.231%) sides out of 156 sides of the skulls examined. They were found in 87 (55.77%) sides out of 156 sides of the skulls examined The parietal foramina were found to be located at a distance ranging from 2 mm-36 mm from the sagittal suture. From the lambda they were found to be located at a distance of 7 mm-56.1 mm. The diameter of the parietal foramina was in the range of 0.86 mm-5.57 mm. Conclusion: Localisation of parietal foramina is important for the neurosurgeon to prevent accidental haemorrhage resulting from damage to the parietal emissary veins.

Keywords

• cranial foramina
• cranium
• diploic veins
• dural venous sinuses
• scalp veins