Anatomy of accessory maxillary sinus ostium with clinical application

Abstract

Background: The “osteomeatal complex” of the middle meatus is a group of anatomical structures that includes; principle maxillary sinus ostium and accessory maxillary sinus ostium. Its beauty lies in its complexity. This osteomeatal complex contributes to the final common drainage pathway of maxillary, anterior ethmoidal and frontal sinuses. Principle maxillary sinus ostium (PMO) is universally present in all population while if extra opening is present in addition to principle maxillary sinus ostium then this is called accessory maxillary sinus ostium. The principle maxillary sinus ostium is opened in the Hiatus semilunaris and it is located on the highest part of medial wall of maxillary sinus as compared to accessory maxillary sinus ostium. Accessory maxillary sinus ostium located in the anterior nasal fontanelle (ANF), posterior nasal fontanelle (PNF), and hiatus semilunaris. Aims & Objective: The endoscopic sinus surgeons must have a detailed knowledge of inconsistent situation of principle maxillary sinus ostium (PMO) and accessory maxillary sinus ostium as there are important structures like orbit superiorly and nasolacrimal duct medially lying adjacent to medial wall of maxillary sinus where above said openings are situated. Materials and Methods: This study was carried out in the department of Anatomy of government medical college, Surat and Surat municipal institute of medical education and research (SMIMER) where 54 cadaveric heads were cut in midsagital section into 108 half heads and then incidence, location and side of accessory maxillary ostium was studied. Results: Among 108 half heads, accessory maxillary ostium was found in 20 (18.5%) half heads. Out of these 20 half heads, in 12 (60%) half heads accessory maxillary sinus ostium is present on right side while in remaining 8 (40%) half heads, it is on the left side. Similarly out of these 20 half heads, 16 (80%) half heads shows unilateral accessory maxillary sinus ostium either on right side or on left side while 4 (20%) half heads shows bilateral accessory maxillary sinus ostium. Out of these 20 half heads, 7 (35%) half heads shows double AMO (which includes 4 (20%) in ANF on the left side, 2(10%) in PNF on the right side and 1 (5%) in HS on the right side) while 13 (65%) were single in number (which includes 9 (45%) in ANF on both left and right side, 4 (20%) in PNF). All double accessory maxillary sinus ostia situated in the ANF and HS were placed in horizontal plane whereas accessory maxillary ostium which was situated in the PNF was placed vertically. Accessory maxillary sinus ostium was varies in size and shape. These accessory maxillary sinus ostia were 0.5 to 5 millimeters in size and round or oval in shape. Similarly out of these 20 (18.5%) half heads in which Accessory maxillary sinus ostia were present 70% Accessory maxillary sinus ostia were found in the anterior nasal fontanelle (ANF), 25% in posterior nasal fontanelle (PNF), and 5% in hiatus semilunaris (H