Manju Singhal et al. Clinical Application of Accessory Maxillary Sinus Ostium 327 International Journal of Medical Science and Public Health | 2014 | Vol 3 | Issue 3 ANATOMY OF ACCESSORY MAXILLARY SINUS OSTIUM WITH CLINICAL APPLICATION Manju Singhal 1 , Deepak Singhal 2 1 Department of Anatomy, Surat Municipal Institute of Medical Education & Research, Surat, Gujarat, India 2 Department of Forensic Medicine & Toxicology, Surat Municipal Institute of Medical Education & Research, Surat, Gujarat, India Correspondence to: Deepak Singhal (dmparam@gmail.com) DOI: 10.5455/ijmsph.2013.301220131 Received Date: 27.12.2013 Accepted Date: 20.02.2014 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 (HS). Most of the accessory maxillary sinus ostia (65%) were single in number at the various places while double accessory maxillary sinus ostia were also found 20% in the ANF, 10% in the PNF 5% in the HS. Conclusion: Clinically the presence of accessory maxillary sinus ostium is extremely beneficial for surgical intervention of the functional endoscopic sinus surgery which is designed to remove the blockage of maxillary sinus ostium and to restore normal sinus ventilation and mucociliary function. Key Words: Accessory Maxillary Sinus Ostium (AMO); Anterior Nasal Fontanelle (ANF); Posterior Nasal Fontanelle (PNF); Hiatus Semiluneris (HS); Principle Maxillary Sinus Ostium (PMO) Introduction Evolution is gradual process by which man attained erect posture as a result, the principle or main maxillary ostium (PMO) come to situated at higher level consequently drainage was no longer duo to gravity. [1] Its higher location along with the improper mucociliary action of the lining mucosa in the maxillary sinus is the leading cause of the obstruction in the ostium which opens at the hiatus semiluneris. Zuckerkandle has observed that obstruction may however be due to anatomical variation or anomaly in the vicinity of PMO. [2] Maxillary sinusitis is therefore the demerit gift of erect posture. [1] The ‘osteomeatal complex’ of the middle meatus is a group of anatomical structures that includes principle and accessory maxillary sinus ostia. Its beauty lies in its complexity. This osteomeatal complex contributes to the final common drainage pathway of maxillary, anterior ethmoidal and frontal sinuses. 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 (AMO). Rice and Scheaffer (1993) termed all extra openings other than a single PMO as accessory maxillary sinus ostium. [3] Accessory maxillary sinus ostium is either congenital or secondary due to disease process as a result of obstruction of principle ostium by maxillary sinusitis or due to anatomical or pathological factors in the middle meatus resulting in the rupture of membranous area known as fontanelle. [4] RESEARCH ARTICLE