The tympanic cavity is an air-filled irregular space within the middle ear in the temporal bone that contains three auditory ossicles (malleus, incus, and stapes) along with their attached muscles. The roof of the tympanic cavity, formed by the tegmen tympani, separates the tympanic cavity from the MCF contents. The tegmen tympani is formed by the petrous and squamous portions of the temporal bone. The suture line between these two portions, the petrosquamous suture, is unossified in young individuals and does not close until adult life. Through this suture, veins from the middle ear pass through to the superior petrosal sinus. The tegmen tympani extends posteriorly to roof the tympanic antrum and anteriorly to cover the semicircular canals.

Its lateral edge corresponds with the remnants of the petrosquamous suture.