Horizontal maxillary sinus septa: An uncommon entity

•The aim of this report is to demonstrate the unexpected antral septa type that compromises elevation of schneiderian membrane.•CT is useful for examining sinus anatomy and successful surgical planing for preventing complications.•As seen on the literature horizontal septas were seen rarely.

IntroductionMaxillary sinus septas are barriers of cortical bone that arise from the floor or from the walls of sinus and may even divide the sinus into two or more cavities. Morphologically maxillary sinus septa are generally oriented in buccopalatinal orientation horizontal or sagittal orientation of the sinus septa is a rare condition.Presentation of CaseThis report presents two sinus lift case, in which observed septa in a horizontal orientation was presented. Both cases were fixed by an implant supported prosthethic restoration.DiscussionSurgeons must know detailed knowledge about maxillary sinus anatomy for successful sinus augmentation. Computed tomography (CT) is useful for examining the maxillary sinus.ConclusionHorizontal-type sinus septa are rarely seen. Surgeons must be aware of septa types and orientations.