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ANATOMY OF THE EXTERNAL EAR
The external ear, housed in the temporal bone, includes the au-ricle (i.e., pinna) and the external auditory canal (Fig. 59-1). The external ear is separated from the middle ear by a disklike struc-ture called the tympanic membrane (ie, eardrum).
The auricle, attached to the side of the head by skin, is composed mainly of cartilage, except for the fat and subcutaneous tissue in the earlobe. The auricle collects the sound waves and directs vi-brations into the external auditory canal.
The external auditory canal is approximately 2.5 cm long. The lateral third is an elastic cartilaginous and dense fibrous frame-work to which thin skin is attached. The medial two thirds is bone lined with thin skin. The external auditory canal ends at the tympanic membrane (Chart 59-1).
The skin of the canal contains hair, sebaceous glands, and ceru-minous glands, which secrete a brown, waxlike substance called cerumen (ie, ear wax). The ear’s self-cleaning mechanism moves old skin cells and cerumen to the outer part of the ear.
Just anterior to the external auditory canal is the temporo-mandibular joint. The head of the mandible can be felt by plac-ing a fingertip in the external auditory canal while the patient opens and closes the mouth.
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