[Middle ear physiology].

The middle ear forms part of the sound transformer mechanism, together with the outer ear and the conducting system of the inner ear. An intermediate sensory organ, sensitive to acoustic vibration, and linked to the inner ear, the middle ear made its appearance during the period of adaptation of marine creatures to a terrestrial habitat; its presence is therefore a phylogenetic requirement. It is classical to ascribe three functions to the middle ear: the transmission of acoustic vibrations from the tympanic membrane to the cochlea, impedance matching between the air in the external auditary meatus and the labyrinthine fluids, and protection of the inner ear by means of the acoustic reflex. If the classical mechanical explanation has been able to explain its function, the conceptualization of its physiology in terms of energy allows an even better understanding, as well as providing and explanation for the paradoxes which arise in clinical practice when the classical model is used.