Last revised by Daniel J Bell on 3 Dec 2019

The mesotympanum (rare plural: mesotympana) forms the main compartment of the tympanic cavity and contains most of the important structures of the middle ear, including most of the ossicular chain

Gross anatomy


The mesotympanum is found in the middle ear.


The middle ear ossicles consist of three small bones, the malleusincus and stapes, which form a mobile chain across the mesotympanum from the tympanic membrane to the oval window. Only the head of the malleus and the body and short process of the incus lie outside of the mesotympanum, in the epitympanum.


There are two muscles, one for the malleus and one for the stapes, which act to damp down over-vibration from low-pitched sound waves. These are, respectively:


The chorda tympani leaves the facial nerve in the facial canal and enters the tympanic cavity through the posterior wall, lateral to the pyramid, lying just underneath the mucous membrane. It runs over the pars flaccida of the tympanic membrane, and the neck of the malleus. It leaves at the anterior margin of the tympanic notch.

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Cases and figures

  • Case 1: middle ear anatomy: annotated CT
    Drag here to reorder.