![]() ![]() The alternative passive route involves reduction in tone of the stylopharyngeus and pterygopharyngeus muscles accompanied by increased inspiratory pressure. The active process has two stages: (1) opening of the pharyngeal orifices by simultaneous contractions of the levator and tensor veli palatini and pterygopharyngeus muscles then (2) opening of the pouch ostia by contractions of dorsal portions of the palatopharyngeus muscles. The investigation offers theoretical evidence that opening of the equine auditory tubes to ventilate the guttural pouch occurs in two different ways, active and passive. Intrinsic tone of the stylopharyngeus and pterygopharyngeus muscles may be part of this active process. Small decreases in simulated inspiratory pressure consistently caused the passive opening of both the pharyngeal orifice and pouch ostium in horse cadavers suggesting that an active counter process may exist in the live horse to maintain closure of the guttural pouch openings during rest and light exercise. Previous reports may reflect, at least in part, a misinterpretation of air pressure measurements within the guttural pouches and nasopharynx. The results of this investigation suggest that regular guttural pouch ventilation during resting respiration does not occur. Torus tubarius (plural: tori tubarii) or cushion of the auditory canal is a mucosal elevation in the lateral aspect of the nasopharynx, formed by the underlying pharyngeal end of the cartilaginous portion of the Eustachian tube.The opening of the Eustachian tube is anterior to the torus tobarius. A 'second orifice' (representing the final entrance to the auditory tube diverticulum) deserves recognition in performing a role in air exchange between the auditory tube, diverticulum and middle ear. ![]() Its larger size and position, further rostral within the nasopharynx compared with other species, cannot be easily explained, but could be important for the proposed brain-cooling function of the guttural pouches however, unlike other species, it may not be the sole regulator of auditory tube aeration. KEYWORDS Eustachian Tube, Inferior Nasal Concha, Inferior Turbinate.The pharyngeal orifice of the equine auditory tube has not been adequately described. So the study will be helpful for radiologist for differential diagnosis and ENT surgeons for endoscopic evaluation in patients with chronic otitis media. CONCLUSION In the present work, the exact position of auditory tube can be located by various measurements. The height was more on right side than on left side. The A-P length on right side was 8.7 mm on right and 7.6 mm on left side, which was statistically significant. Oval shape more common on right side (52%) and triangular on left (48%). RESULTS The vertical length and A-P length was taken and shape was observed. The mean and standard deviation of these parameters were calculated. The pharyngeal opening of Eustachian tube was observed for its shape, size and important measurements taken with the help of sliding vernier calliper. MATERIALS AND METHODS Study was carried out, 50 sagittal sections (25 right side and 25 left side) of head and neck specimens from adult formalin fixed cadavers from the Department of Anatomy, Krishna Institute of Medical Sciences Deemed University, Karad, Maharashtra, India. It is an important landmark for endoscopic evaluation in patients with chronic otitis and also for the transnasal approach to the infratemporal fossa. The canal is nearly 1 inch (2. Abstract : Eustachian tube extends from the anterior wall of the middle ear to the lateral wall of the nasopharynx at the level of inferior nasal choncha. What is the auditory meatus External auditory canal, also called external auditory meatus, or external acoustic meatus, passageway that leads from the outside of the head to the tympanic membrane, or eardrum membrane, of each ear.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |