StructureThe incus is the second of the ossicles, three bones in the middle ear which act to transmit sound. It is shaped like an anvil, and has a long and short crus extending from the body, which articulates with the malleus. The short crus attaches to the posterior ligament of the incus. The long crus articulates with the stirrup at the lenticular process. The superior ligament of the incus attaches at the body of the incus to the roof of the tympanic cavity.
FunctionVibrations in the middle ear are received via the tympanic membrane. The malleus, resting on the membrane, conveys vibrations to the incus. This in turn conveys vibrations to the stapes.
History"Incus" means "anvil" in Latin. Several sources attribute the discovery of the incus to the anatomist and philosopher Alessandro Achillini. The first brief written description of the ''incus'' was by Berengario da Carpi in his ''Commentaria super anatomia Mundini'' (1521). Andreas Vesalius, in his '' De humani corporis fabrica'', was the first to compare the second element of the ossicles to an anvil, thereby giving it the name ''incus''. The final part of the long limb was once described as a "fourth ossicle" by Pieter Paaw in 1615.
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