The posterior superior alveolar artery arises from the maxillary artery in the pterygopalatine fossa and descends on the posterior maxillary surface, sending branches through the posterior alveolar canals to supply the upper molar teeth and their supporting bone, the maxillary sinus membrane, and the buccal gingiva of the upper molars. A branch runs through the lateral maxillary sinus wall as the posterior superior alveolar vessel.
The posterior superior alveolar artery running within the lateral sinus wall is a critical structure in sinus lift (Schneiderian membrane elevation) procedures before implant placement in the posterior maxilla. CBCT imaging identifies this intraosseous vessel before surgery; inadvertent injury causes intraoperative bleeding into the sinus that clouds the surgical field. The Schneiderian membrane elevation must stay strictly subperiosteal to avoid this vessel. Vessel diameter over 1 mm significantly increases haemorrhage risk and may necessitate modification of the surgical approach.
CBCT-identified intraosseous posterior superior alveolar artery in the lateral maxillary sinus wall is at risk during lateral window sinus augmentation; vessel injury produces significant intraoperative bleeding and sinus membrane disruption, managed by bipolar coagulation and collagen haemostat packing before proceeding with the bone graft.
