Study of Jugular Foramen – A Case Report

The jugular foramen at the base of the skull varies in shape and size the foramen lies at the petrous part of temporal bone and behind by the occipital bone. It’s irregular in shape. Usually the right foramen is larger than the left. The variation in the foramen is observed in different racial group and sexes. The shape and size of foramen is inversely related to size of sigmoid sinus. Petrosal portion contains the inferior petrosal sinus. Sigmoid portion receives the sigmoid sinus. Intrajugular portion contains cranial nerves IX, X and XI. AIM: To analyze the length and width of jugular foramen. To determine the side dominance of the foramen. MATERIALS AND METHODS: A total of 32 jugular foramen in dry adult skulls from Department of Anatomy, CHRI were used for the present study. Sagittal and transverse diameters were measured using digital vernier caliper. OBSERVATIONS: The overall dimensions of Jugular foramen were recorded on both sides. The mean transverse diameter (width) on the right and the left side were 11.779mm and 10.901mm respectively. The mean sagittal diameter (length) on the right and left side were 10.141mm and 09.025mm. In 62.5% of cases the right foramen was larger , in 37.5% of cases left foramen was larger than the right. Dome was found bilaterally in 50% of cases, The unilateral presence of dome was equally distributed to both sides. Jugular process was found bilaterally in 18.75%, right side 31.25% and left side in 18.75% of cases. The process was absent in 31.25% cases. Complete Septation of the foramen was found in 12.5% on right side, 6.25% on left side. Partial Septation was seen in 87.5% on right side, in 93.74% on left side. CONCLUSION: In comparison with the previous studies, the width of the Jugular foramen is slightly higher where as the length is slightly lower. There is an increase in the occurrence of bony partition compared to the previous study. Dimension, dome and Septation were significantly higher on right side than on left. Jugular foramen serves as an important land mark during surgeries of posterior cranial fossa.