Background: Computerized tomography scan can show the detailed anatomy of the nose and paranasal sinuses. The sphenoid sinus is a very important corridor for the skull base because of its central position. This sinus has a great range of variation and can put structures around at risk during surgery. This study aims to examine the variation of the sphenoid sinus, and its relation to other structures around it, in this sample of Iraqi patients. Materials and Methods: CT scans of 122 patients, were obtained, and submitted for examination and measurements, during the period between September 2020 and September 2021. Observation of The sphenoid sinus pneumatization pattern, clival extension, Onodi cell, and lateral pneumatization of SS. As well as the SS measurements including the suprasellar depth, presellar depth, subsellar depth and sinus height. Exclusion was made for those with a previous history of sinus surgery and patients with tumours, sinonasal trauma or sinus fungal infection. Results: This study involved CT scans of 122 patients. The postsellar type of pneumatization was seen in 47.6%, sellar type 35.2% and presellar type 17.2%, while we did not see conchal type in this sample. Onodi cell was seen in 27.9%. The optic nerve, maxillary nerve, vidian nerve, and Carotid artery were protruding into the sinus in (35.2%), (14.8%), (46.8%) and (40.2%) respectively. We noticed that the full lateral type of lateral pneumatization is significantly associated with both vidian nerve protrusion and maxillary nerve protrusion; while right and left optic nerve protrusions were significantly associated with the corresponding side lesser wing type of lateral pneumatization, P - Value 0.001. Conclusion: Pneumatization of the sphenoid sinus has a great degree of variation in the population. Each patient has a different pneumatization pattern.