The Tympanic Membrane is liable to Inflammations in common with the meatus on the one hand and the middle ear on the other. Hence arise various thickenings and adhesions, sometimes with calcareous deposition, chiefly in connection with diseases of the middle ear. Hence also arise Perforations of the membrane, which have frequently serious consequences for the tympanic cavity. Rupture is of occasional occurrence, usually in consequence of condensation of the air in the external meatus as from a blow on the ear, but also from instruments thrust into the ear.