Pronunciation: [ɪnkˈʌs] (IPA) 
The word "incus" is often misspelled as "inkus," which is incorrect. The correct spelling is "in-kus," with stress on the first syllable. The IPA phonetic transcription for "incus" is ˈɪŋkəs. The reason for this spelling is that the "i" is pronounced as "in," and the "c" is followed by a silent "u," making the "c" sound like "k." "Incus" refers to a small bone in the middle ear, and is an important part of the hearing process.
The incus, also known as the anvil, is one of the three small bones in the middle ear of humans and other mammals. As part of the auditory ossicles, the incus plays a fundamental role in the transmission of sound from the outer ear to the inner ear.
Anatomically, the incus is located between the malleus (hammer) and the stapes (stirrup). It is shaped like an anvil, with a body and two limbs. The body of the incus connects to the tympanic membrane, while one of its limbs connects to the malleus. The other limb, called the long process, is connected to the stapes.
During the hearing process, when sound waves enter the ear canal and hit the eardrum, the eardrum vibrates, which in turn causes the malleus to move. The malleus then transfers these vibrations to the incus, amplifying them. Finally, the vibrations are transmitted to the stapes, which passes them on to the inner ear.
The incus, along with the malleus and the stapes, forms a chain-like structure that together form a mechanical impedance match, efficiently transferring sound vibrations from the air to the fluid-filled cochlea within the inner ear. This process is vital for the perception of sound and enables humans and other mammals to hear and interpret a wide range of auditory stimuli.
Anvil, the middle of the three ossicles in the tympanum, comparable in shape to a bicuspid tooth; it has a body (corpus incudis) and two limbs or processes (crus longum and crus breve); at the tip of the long limb is a small knob, processus lenticularis, which articulates with the head of the stapes.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "incus" comes from Latin, where it means "anvil". It is derived from the Proto-Indo-European root "*h₂nḱ-", meaning "sharp". The Latin word "incus" was used to describe the anvil due to its shape resembling that of the ancient blacksmith's anvil. This term was later adopted in the field of anatomy to refer to one of the three small bones in the middle ear.
