Jugular Foramen of Adult Human Skull and its Clinical Significance in Population of Eastern India: A Cross-sectional Study

Abstract

Introduction: Jugular foramen is a complex irregular bony canal located at the base of the skull between the condylar part of occipital bone and petrous part of temporal bone. It allows passage of important nervous and vascular structures. These are ninth, tenth, eleventh cranial nerves, sigmoid sinus continued as the superior bulb of internal jugular vein and inferior petrosal sinus, meningeal branches of the ascending pharyngeal and occipital arteries. Jugular fossa has a septum and a dome. The dome lodges the superior bulb of internal jugular vein. The septum divides the foramen into two compartment, antero- medial and postero-lateral. There is a wide variation in shape, size and septation of jugular foramen in different regions of globe which have been studied by different authors in different periods of time. Many tumours may arise in this region causing compression of the vital structures passing through it. Surgery is the treatment of choice in these cases. Successful neuro surgeries involving this region require detailed knowledge about the anatomical variation of the jugular foramen. Aim: To study and compare the morphology of jugular foramen, its various dimensions, shape, size and septation which is related to the size of internal jugular vein. Materials and Methods: A cross-sectional descriptive study was carried out on 85 adult dry human skulls, collected from the Anatomy Department as well as from the first year Bachelor of Medicine and Bachelor of Surgery (MBBS) students of different Medical colleges of West Bengal from September 2020 to June 2021. Presence of septa were observed and anteroposterior (AP), mediolateral diameter (ML diameter) were measured by using vernier caliper. Then the area was calculated. Data collected were compiled in tabular form. They were analysed by using Statistical Package for Social Sciences (SPSS) statistics version 20.0 and paired t-test and chi-square tests were applied. Results: In the total 85 skulls studied, the area of jugular foramen was larger on right side in 91.76% and on left side in 8.24% of skull. The AP diameter was less than the ML diameter and areas in all cases. But both the diameters were significantly (p-value<0.001) larger on right side than the left. Complete septation was present in right side of 34 foramina and in left side of 17 foramina. Partial or incomplete septation was present on right side of 51 foramina and left side of 68 foramina. Conclusion: The study revealed variation in shape, size and septation in different skulls and also bilateral variation in same skull. It has immense value to radiologists, Ear Nose Throat (ENT) surgeons, neuro-surgeons and radiologists who deal with the diagnosis and management of space occupying lesions surrounding the jugular foramen.