Why should Posterior wall preffered during surgery

Posterior wall should not be perforated during surgery. This limits bleeding from the pterygoid plexus or branches of the maxillary artery (Posterior superior alveolar artery) as complications. Medial wall separates the sinus from the nasal fossa. The maxillary ostium which drains the sinus into the middle meatus of the nasal cavity is located in the highest, most medial aspect of the sinus wall. Although its high location makes dependant drainage (causing increased susceptibility to infection) difficult, its location is favourable for the implant surgeon in that, it is unlikely to become obstructed by the routine maxillary augmentation in the inferior sinus region.