And the stapedius muscle, which normally stabilizes the stapes, can become weakened due to damage as well. The tensor timpani muscle normally dampens loud sounds, and its function can be impaired when it's damaged.

Hyperacusis: Resulting from infection or trauma, hypersensitivity to noises can occur when certain muscles in the inner ear become damaged.

Injuries may cause ossicular chain discontinuity, either directly or as a result of subsequent inflammation in the middle ear.

Trauma: Head trauma can lead to an injury, such as a skull fracture.

Congenital malformation: Birth defects can include abnormalities such as malformation or absence of one or more of the ossicles, potentially with ossicular chain discontinuity.

If untreated-and depending on their location-they may enlarge and impact the ossicles, affecting their function and leading to hearing loss.

Cholesteatoma: Cholesteatomas are noncancerous growths in the middle ear.

Most often, this causes the base of the stapes to become affixed to the oval window, preventing the transmission of sound vibrations.

Otosclerosis: This abnormal growth of tissue in the middle ear can severely impact the mobility of the ossicles, leading to hearing loss.

COM can cause erosion of the malleus, which can spread an infection to the meninges, the protective covering surrounding the brain. This leads to damage of the ossicles over the long-term.

Chronic otitis media (COM): Middle ear infections can frequently recur or might not resolve.

These are then transmitted to the brain through the vestibulocochlear nerve. The motion of the stapes produces tiny waves, which are picked up by the receptor cells, essentially converting mechanical information into electrical signals. Beyond it is the cochlea, a fluid-filled structure that’s shaped like a snail and has thousands of receptor cells. The bodys three smallest bones- the hammer, anvil, and stirrup found in the middle ear. A spiral shakes ridge of epithelium in the cochlear duct lined with hair cells that serve as heating receptors.

Beyond the oval window: After the vibrations pass through the ossicles, they cause the oval window to move. A tiny bone that passes vibrations from the eardrum to the anvil.

In this way, these bones act as a kind of amplifier of sound.

Amplification: The base of the stapes attached to the oval window is much smaller than the eardrum, and the force of the vibrations is increased.

When the malleus picks up the movement, it vibrates, leading to the vibration of the other ossicles too.

Transmission: The malleus is attached to the eardrum, and to the other ossicles in a chain-like sequence.

Vibration of the eardrum: Soundwaves enter the external acoustic meatus (ear canal), and are channeled to the eardrum, causing it to vibrate.

These are commonly referred to as “hammer, anvil, and stirrup.” Conveniently, the malleus is like an orientation compass for the examiner in an ear with normal anatomy.Ĭompare the right ear and the left ear taken from the same patient. The formal names of the three bones are malleus, incus, and stapes. This is the first of three bones in the middle ear that communicates the movements of the eardrum, from sound waves to the inner ear. When sound waves enter the ear canal and strike the eardrum, they cause the eardrum to vibrate. The primary function of the ossicles is to transmit sound vibrations from the eardrum to the inner ear. The malleus points like an arrow towards the face of the patient.Ī prominent feature of the ear exam is the presence of the malleus bone. The malleus (hammer), incus (anvil), and stapes are the names of these bones (stirrup).

It’s easy to tell because of the orientation of the malleus bone. How can you tell which ear the image is from? This is one of our favorite questions to ask learners because the answer is simple and useful. Unfortunately, the examiner forgot to make note of which ear the image is from for the medical record. This image is obtained Wispr Digital Otoscope.

A healthy 23-year-old female presents for a routine sports physical exam.

Hammer anvil and stirrup proper names