Anatomical study of critical features on the posterior wall of the maxillary sinus: Clinical implications

OBJECTIVES/HYPOTHESIS: Endonasal approaches to the pterygopalatine fossa for epistaxis or as part of a transpterygoid approach have been popularized somewhat by the ability to control the terminal branches of the maxillary artery (MA). Surgical landmarks are useful to identify these arteries. Therefore, identification of surface features on the posterior wall of the antrum that reflect the position of deeper structures within the pterygopalatine fossa would help predict anatomical position and orientation. STUDY DESIGN: Describe the incidence of identifiable markings on the posterior wall of the maxillary sinus and ascertain their nature. METHODS: An anatomical study of 18 cadaveric specimens noting and recording the presence, location, and number of prominences on the posterior wall of the antrum. After removing the bony wall, structure in the pterygopalatine fossa corresponding to the surface markings was noted. RESULTS: Two prominences were identified. Prominence (P)1 extended from the upper part of the posterior wall of the maxillary sinus to the inferior orbit and corresponded to the infraorbital nerve. P2 was located at the middle part of the posterior wall, below P1, and corresponded to the MA. P2 was located medial to a vertical "drop line" where P1 connected to the posterior wall. P1 and P2 were found in 41.7% and 22.2%, respectively, of the specimens. CONCLUSIONS: This study defines features on the maxillary sinus posterior wall from an endoscopic perspective. These landmarks may be useful to identify the MA and its branches during surgery within the pterygopalatine fossa. LEVEL OF EVIDENCE: N/A.