The eardrum, also called the tympanic membrane, is located at the innermost part of the external auditory canal and is the dividing line between the outer ear and the middle ear. The tympanic membrane is the membrane between the external ear canal and the tympanic chamber. The tympanic membrane is very thin and the tension of the tympanic membrane is a translucent membrane, and the tympanic membrane is the innermost part of the external ear canal and, at the same time, the outermost wall of the middle ear tympanic chamber. Therefore, when pulling out the ears, the length of the spoon or cotton swab should not exceed 2 cm for adults; if it exceeds 2 cm, it will injure the eardrum and cause perforation of the eardrum. The tympanic membrane is a translucent membrane that is composed of the epithelial, fibrous and mucosal layers in order from outside to inside. The average height of the tympanic membrane is 9 mm, the width is 8 mm and the thickness is about 0.1 mm. The lower part of the tympanic membrane is called the tense part and the upper part is called the relaxed part.