Morphometric Study of Pharyngeal Orifice of Auditory Tube and Its Clinical Relavance

Background The Auditory tube (AT) extends from the anterior wall of the middle ear to the lateral wall of the nasopharynx, approximately at the level of the inferior nasal concha. The pharyngeal orifice of AT being an important landmark for endoscopic avaliation in patients with chronic otitis and also for the transnasal approach to the infratemporal fossa, the present study was undertaken to locate the pharyngeal orifice of auditory tube in relation to the important anatomical landmarks in fetuses and adults. Material and methods The study was carried out on 25 sagittal head and neck sections of adult formalin fixed cadaversand 25 sagittal head and neck sections of fetuses. The anatomical landmarks with reference to AT taken were upper border of C1 vertebra, posterior end of hard palate (HP), midpoint of choana (PC), tip of uvula (U) and midpoint of floor of sphenoid sinus (SP). The distances from these landmarks to the pharyngeal orifice of AT were measured using digital vernier calipers. Results The mean and standard deviations of the distances were calculated and tabulated. All the measured distances were higher on left side except AT to SP in fetuses, whereas in adults all the distances were higher on left except for AT to U. Differences were not statically significant. Conclusion As the pharyngeal orifice of AT is an important landmark for endoscopic availation in patients with chronic otitis, so the present study would be useful to locate the pharyngeal orifice of AT in relation to important anatomical landmarks.