Tyson J
Michelle R
Ethan L
Allyson L
Ursula S

The stapes or stirrup is the stirrup-shaped small bone or ossicle in the middle ear which attaches the incus to the fenestra ovalis,the "oval window" which is adjacent to the vestibule of the inner ear. It is the smallest and lightest bone in the human body.
The stapes transmits the sound vibrations from the incus to the membrane of the inner ear inside the fenestra ovalis. The stapes is also stabilized by the stapedius muscle, which is innervated by the facial nerve.
In non-mammalian vertebrates, the bone homologous to the stapes is usually called the columella; however, in reptiles, either term may be used.




The middle ear; includes the eardrum (tympanic membrane) and the three bones of the middle ear, the malleus ("hammer"), incus ("anvil"), and the stapes (pronounced STAY-PEAZ, "the stirrup").




Otosclerosis is the abnormal growth of bone of the middle ear. This bone prevents structures within the ear from working properly and causes hearing loss. For some people with otosclerosis, the hearing loss may become severe. Otosclerosis usually affects the last bone in the chain, the stapes, which rests in the oval window. The abnormal bone fixates the stapes in the oval window and interferes with sound passing waves to the inner ear. Otosclerosis usually causes a conductive hearing loss, caused by a problem in the outer or middle ear. Occasionally it may cause a sensorineural hearing loss, which is damaged sensory cells and/or nerve fibers of the inner ear, as well as a conductive hearing loss.

Cause
The cause of otosclerosis is not fully understood, although research has shown that otosclerosis tends to run in families and may be hereditary. On average, a person who has one parent with otosclerosis has a 25 percent chance of developing the disorder. If both parents have otosclerosis, the risk goes up to 50 percent. Research shows that white, middle-aged women are most at risk. Some research suggests a relationship between otosclerosis and the hormonal changes associated with pregnancy. While the exact cause remains unknown, there is some evidence associating viral infections (such as measles) and otosclerosis.

Symptoms
· gradual hearing
· people first notice that they cannot hear low-pitched sounds or whispers
· dizziness, balance problems, or tinnitus (sensation of ringing, roaring, buzzing, or hissing in the ears or head)

Diagnosis
· examination by an otolaryngologist (ear, nose, and throat physician) or otologist (ear physician)
· An audiologist is a hearing health care professional who is trained to identify, measure, and rehabilitate hearing impairment and related disorders.
o may produce an audiogram (a graph that shows a person's hearing sensitivity) and a tympanogram (a graph that shows how well the middle ear functions to conduct sound).

Treatment
· stapedectomy
o a surgeon (otolaryngologist or otologist) bypasses the diseased bone with a prosthetic device that allows sound waves to be passed to the inner ear.
o In rare cases, surgery can worsen the hearing loss.
· Hearing aids
o If hearing loss is mild o Help in situations that include persistent hearing loss. o designed to compensate for a hearing loss by amplifying sound