Eardrum: Structure, Function & Diseases

The eardrum is located in the human ear. It is a thin membrane that sits between the ear canal and the middle ear. It performs important tasks including protecting the middle ear and also in transmitting sound. Injuries to the eardrum can therefore affect hearing in some circumstances.

What is the eardrum?

Anatomical structure of the ear including the eardrum. Experts refer to the eardrum as a part of the human ear (strictly speaking, almost all land-dwelling vertebrates have an eardrum). It is a thin membrane that sits at the end of the internal auditory canal just in front of the middle ear. The membrane has a thickness of about 0.1 mm and a diameter of up to 10 mm. The eardrum performs various functions and is involved in sound transmission, among other things. Accordingly, damage to the membrane, for example by violent impact, can lead to a partial loss of hearing ability. However, nowadays medical science is often able to repair the rupture in the eardrum by surgical intervention.

Anatomy and structure

Experts divide the eardrum into three distinct layers, from the outside in, an epithelial layer, a fibrous layer, and a mucosal layer. The membrane is not under tension, but is curved inward like a funnel and capable of vibration. At its lowest point, the eardrum is connected to the malleus, the first of the ossicles. In this way, it transports the sound it receives from the outside to the inner ear. It has very sensitive nerve plexuses. For this reason, even light touches are felt as painful. The blood supply to the eardrum occurs through a double network of fine blood vessels.

Functions and tasks

The eardrum primarily performs two important functions in the human ear. The first is a protective function: the eardrum is located directly at the end of the internal auditory canal and forms, so to speak, a kind of endogenous “closure” for the middle ear behind it. In this way, the thin but elastic membrane prevents the penetration of dirt particles or liquids. These could easily lead to painful inflammations in the area of the middle or even the inner ear, requiring medical attention. The second task of the eardrum is directly related to hearing: The thin membrane picks up sound waves entering the ear canal and is caused by them to vibrate accordingly. Since the eardrum is connected to the hammer (more precisely, the hammer handle), sound is transmitted directly from the vibrating membrane to the ossicles, and from there it reaches the inner ear.

Diseases

Because the eardrum is directly involved in the hearing process, it is a very sensitive membrane. This can be damaged by a number of things. A loud bang (such as from an explosion) or a direct blow to the ear can cause the eardrum to rupture. This is technically called a rupture and is colloquially referred to as a “ruptured eardrum.” Mechanical action on the membrane (for example, using cotton swabs to clean the inner ear) can also cause the eardrum to perforate. The same applies to severe middle ear infections or skull fractures. An unpleasant side effect of a defective eardrum is the fact that pathogens can enter the ear in this way, for example through water penetration. In addition, a damaged eardrum can always bring with it limitations in hearing. The extent to which hearing is actually affected depends on the location and size of the hole in the membrane. In many cases, there is spontaneous healing after such a rupture, so that the eardrum grows back together completely on its own. If this self-healing fails to occur, the membrane can be restored by means of a surgical procedure. This involves using the patient’s own tissue, for example from a muscle, to permanently seal the tears that have formed in the eardrum. To avoid permanent damage, a doctor should always be consulted if a perforated eardrum is suspected.

Typical and common ear diseases

  • Ear drum injuries
  • Ear flow (otorrhea)
  • Otitis media
  • Ear canal inflammation
  • Mastoiditis
  • Hearing loss