The Schneiderian membrane, also called the Schneiderian epithelium, is the lining of the paranasal sinuses and nasal cavity. It’s unique in that the ciliated columnar lining is ectodermally derived and features goblet cells. The neighboring respiratory epithelium, which appears similar to the Schneiderian membrane, is derived from the endoderm. One of the most common complications that can occur during a sinus grafting surgery is a tear or perforation in the Schneiderian membrane of the maxillary sinus. If this occurs, typically, the surgeon will repair the perforation at the same time the graft is placed, and few additional risks of complications exist. However, in some cases, patients will develop an infection in the maxillary sinus or surrounding areas of the maxillofacial complex after a substantial or complete tear in the membrane. This infection is serious and may result in the failure of a recently completed bone graft or dental implant.