Eardrum

Lore & Background

The tympanic membrane is oriented obliquely in the anteroposterior, mediolateral, and superoinferior planes, with its superoposterior end lateral to its anteroinferior end. It relates superiorly to the middle cranial fossa, posteriorly to the ossicles and facial nerve, inferiorly to the parotid gland, and anteriorly to the temporomandibular joint. The eardrum is divided into the pars flaccida and the pars tensa; the pars flaccida is associated with Eustachian tube dysfunction and cholesteatomas, while the pars tensa is more commonly associated with perforations.

Reader's Guide

The eardrum is essential for hearing, converting airborne sound vibrations into mechanical motion of the ossicles. Rupture or perforation can lead to conductive hearing loss, though most unintentional ruptures heal spontaneously within two to four weeks. Surgical myringotomy is performed to relieve pressure from middle ear infections, and tympanostomy tubes may be inserted to maintain aeration. The Bajau people of the Pacific intentionally rupture their eardrums early in life to facilitate diving, often resulting in hearing difficulties later. The eardrum's nerve supply involves multiple cranial nerves, and its examination reveals a characteristic cone of light at the 5 o'clock position.

Did You Know?

• The eardrum is also called the tympanic membrane or myringa.
• The pars tensa is the region more commonly associated with perforations.
• Between 80 and 95 percent of ruptures recover completely within two to four weeks.
• The Bajau people intentionally rupture their eardrums at an early age to facilitate diving.