For radical surgery of the past, the precise definition of the clefts of the paranasal sinuses was of limited significance. In the recent years, the transsphenoidal approach to the pituitary gland has come into practice and the study of the surgical anatomy and relationships of the sphenoid sinus has gained increased significance. To better define this anatomy, 20 sphenoid sinuses in cadavers were dissected to reveal important anatomical relationships, dimensions, volume and pneumatization of the sphenoid sinus. The results of the study are discussed with particular reference to the important surgical anatomical features of the sphenoid sinus. The results also point towards the possibility of racial variations in terms of relationships of the sphenoid sinus to internal carotid artery and optic nerve in the Indian population