The eardrum is approximately 0.1mm thick. The so-called eardrum, or tympanic membrane as it is clinically known, is located between the external auditory canal and the tympanic cavity and serves as a protective barrier for the middle ear drum. The tympanic membrane is located deep in the external auditory canal, about 2.5-3.5 cm from the opening of the external ear canal, and is distributed in an oval shape and at a slight angle of about 45 degrees to the lower front. The tympanic membrane is approximately 9 mm high, 8 mm wide, and 0.1 mm thick and is usually composed of three layers: the outer epithelial layer is continued by the epithelium of the external auditory canal skin; the middle layer is the lamina propria, composed of fibrous tissue, which is distributed radially and circumferentially, respectively; and the inner layer is the mucosa, which is continued by the mucosa of the middle ear drum.