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Updated: May 31, 2025
Waves of sound reach the ear, and are directed by the concha to the external passage, at the end of which they reach the tympanic membrane. When the sound-waves beat upon this thin membrane, it is thrown into vibration, reproducing in its movements the character of the air-vibrations that have fallen upon it.
A most curious feature of the ear is the chain of tiny movable bones which stretch across the cavity of the middle ear. They connect the tympanic membrane with the labyrinth, and serve to convey the vibrations communicated to the membrane across the cavity of the tympanum to the internal ear.
The external ear consists of an expanded portion known as the pinna or auricle, and of a passage, the auditory canal or meatus, leading inwards from it. The surface of the auricle is convoluted to collect and transmit the vibrations of air by which sound is produced the auditory canal conducts these vibrations to the tympanic membrane. Many animals move the auricle in the direction of the sound.
Thomka in 1895 reported a case of supernumerary tympanic ossicle, the nature of which was unknown, although it was neither an inflammatory product nor a remnant of Meckel's cartilage. Absence of the Limbs. Those persons born without limbs are either the subjects of intrauterine amputation or of embryonic malformation.
The act of restoring a limb, etc., to its natural position after it has been flexed or bent; the opposite of flexion. Fauces. The part of the mouth which opens into the pharynx. Literally, "a window." Fenestra ovalis and fenestra rotunda, the oval and the round window; two apertures in the bone between the tympanic cavity and the labyrinth of the ear. Ferment.
Mott proved that the membrana tympani was not necessary for good hearing, that in fact when it was punctured, a deaf man could in many cases be made to hear, and in fact it improved the hearing in general; the only reason why the tympanic membrane was not punctured oftener was that dust, heat, and cold were apt to injure the middle ear. In closing his paper Dr.
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