![]() ![]() It is about 4 cm in length when measured from the tragus, and 2.5. This clinical study was undertaken to bring together isolated information, to present illustrative cases showing lesions of the external auditory canal and. The narrowest part of the external auditory canal is called the isthmus and lies at the junction of the cartilaginous and bony portions of the canal 5. The external acoustic meatus is a bony-cartilaginous, tubular component of the external ear. A normal variant defect in the anteroinferior aspect of the osseous part of the canal that connects with the temporomandibular joint is known as the foramen tympanicum (foramen of Huschke). The skin of this inner part is directly applied to periosteum, with no subcutaneous tissue present. The roof and upper part of the posterior wall arise from the squamous part of the temporal bone 4. The anterior wall, floor, and lower part of the posterior wall arise from the tympanic part of the temporal bone 3,4. The EAC is easily delineated, measuring 2.5 cm in length, extending from the external auditory meatus to the tympanic membrane. The medial two-thirds is surrounded by bone. Defects in the cartilaginous part of the canal, which allow transmission of infection and malignancy, are known as fissures of Santorini. The lateral one-third is bounded by a fibrocartilaginous tube continuous with the auricle 3. Because of its small size and virtual immobility, the auricle in humans is less useful in sound gathering and direction finding than it is in many animals. It also serves as the outer wall of the tympanic cavity separating it from the external auditory canal. The middle ear, known as the tympanic cavity, is composed of three. The auricle, the visible portion of the outer ear, collects sound waves and, with the concha, the cavity at the entrance to the external auditory canal, helps to funnel sound into the canal. The eardrum separates the outer ear from the middle ear. The external auditory canal is typically 2.5 cm in length and is S-shaped. The external auditory canal connects the outer ear to the middle ear. ![]() or pus in the external ear canal or suffering from an ear infection. There are also middle and inner ear infections that affect deeper structures of the. The ear canal can become clogged with earwax, which causes the eardrum to bulge out. As the term external auditory meatus is variably used to refer to the canal itself or the porus acusticus externus (the round lateral opening), it may be better to use the term external auditory canal rather than meatus to avoid potential confusion. In general, an otitis is external, and touches the external auditory canal.
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