TY - JOUR A1 - , T1 - Classification, neurovascularrelations and ostia of the sphenoid air sinus: a cadaveric study JO - Eur. J. Anat. SN - 1136-4890 Y1 - 2020 VL - 24 SP - 99 EP - 109 UR - http://www.eurjanat.com/web/paper.php?id=190483nn KW - Sphenoid sinus Paranasal sinus Neurovascular relations Pneumatisation Endo-scopic endonasal trans-sphenoidal procedures N2 - The sphenoid air sinus is located deep at the base of the skull and is intimately related to deli-cate neurovascular structures. The purpose of this study was to describe the variations of the sphe-noid sinus in relation to pneumatisation within the sphenoid bone, its ostium and the structures relat-ed to the walls of the sinus. Twenty-five cadaveric specimens were cut mid-sagittally and studied bi-laterally (n=50). The pre-sellar, sellar and post-sellar sphenoid sinus types were observed in 16%, 36% and 48% cases, respectively. The protrusion of the internal carotid artery (ICA) in relation to the sinus walls was observed in 70% cases, while bulges of the optic (ON), maxillary (MN) and Vidian (VN) nerves were observed in 56%, 32% and 22% cases, respectively. Protrusions of ICA, ON and VN were prevalent in post-sellar sinuses and the bulge of MN was prevalent in the sellar sinuses. The ICA had a longer course in sellar and post-sellar sphenoid sinuses. The sphenoid sinus osti-um shape was oval in 72.55% cases and round in 27.45% cases. The ostia were located superiorly on the anterior wall of the sinus in 34.69% cases and in the middle in 65.31% cases. Knowledge on the level of complexity and variability of the sphe-noid sinus plays a pivotal role in preparing for saferendoscopic trans-sphenoid surgical approaches. ER -