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Other Terms: Auditory ossicles, Auditory ossicles set, Ossicula auditoria, Ossicula auditus
This small series of bones represent one of the great dialogues of evolutionary biology. What currently function as transmitters and amplifiers of sound, were once bones of the vertebrate jaws. As the anterior bones of the vertebrate jaw increased in size and the jaw joint shifted rostrally, the posterior jaw elements were freed for additional functional possibilities. Vertebrates modified these bones into the vibrating ossicles that made hearing air born vibrations a reality.
Auditory comes from the Latin verb audire meaning to hear. Ossicles is the diminutive of the Latin word ossis meaning little bones. This term is usually used only in reference to the small bones of the middle ear. Although they were undoubtedly known by early anatomists, the first clear description of these bones was by Berengarius of Carpi in 1514.
The small synovial articulations formed between the malleus and incus and the incus and stapes help to amplify the sound waves received at the tympanic membrane, transferring the waves to the transducers of the inner ear.
The ear ossicles ossify endochondrally replacing the cartilage anlagen formed from the dorsal ends of the first and second branchial or pharyngeal arches.