Background: Proper CT scan evaluation of structures related to the sphenoid sinus is very important before any skull base surgery through the endoscopic transsphenoidal approach. Internal carotid artery (ICA) is one such structure in the vicinity of the sphenoid sinus which if injured due to improper radiological assessment, can cause life-threatening complications of the sinus surgery. This study aimed to know the prevalence of dehiscence in the wall of the internal carotid artery and the resultant protrusion in the sphenoid sinus. Materials and Methods: This was a retrospective study conducted on 150 patients who presented with sinus disease. Their CT scans were studied for the presence of any dehiscence in the wall of the internal carotid artery and also protrusion of the internal carotid artery into the sphenoid sinus. The result was analyzed as a percentage and the ‘p’ value was calculated using Fischer’s exact test. Results: The presence of a dehiscent carotid artery wall was found in fifteen cases, eight of them were males and seven were females. On applying Fisher’s Exact test, the ‘p’ value was calculated as 0.786. Protrusion of the internal carotid artery into the sphenoid sinus was found in forty cases, eighteen of them were males and twenty-two were females. The ‘p’ value was calculated as 0.2731. Conclusion: This normally looking anatomical variation is very dangerous if ignored before embarking upon surgery. The study will be helpful to surgeons who work on the skull base region and perform endoscopic sinus surgeries, to avoid inadvertent injury to the internal carotid artery.