Table of ContentsView AllTable of ContentsAnatomyFunctionAssociated ConditionsRehabilitation
Table of ContentsView All
View All
Table of Contents
Anatomy
Function
Associated Conditions
Rehabilitation
Problems affecting the ossicles can include congenital defects or ossicular chain discontinuity, in which the bones aren’t connected properly. These issues can lead to partial or total deafness, as well as other hearing problems.
The three ossicles are connected to each other via joints, which allow the bones to move in response to the motion of the eardrum.
Verywell / Laura Porter
Structure and Location
Here’s a quick breakdown of each ossicle.
Malleus (Hammer)
The largest of the ossicles, the malleus has:
On the inner (anterior) side, the oval-shaped head connects to the incus via a small, saddle-shaped facet joint with a larger upper portion and a smaller lower portion.
The neck connects the head to the handle, which extends downward, curling forward slightly and narrowing as it joins the lower portion of the eardrum at the spatulate process of the malleus, which is a tiny projection.
The tensor timpani muscle is a small muscle that helps dampen sounds that are too loud. The tendon of the tensor timpani muscle inserts into a small protrusion. Just below the neck, the anterior process of the malleus is a tiny protrusion that terminates in a small fissure in thetemporal bone(a part of the skull).
Incus (Anvil)
The body of the incus is the larger, upper portion of this bone. It attaches to the malleus at the incudomalleolar joint.
Stapes (Stirrup)
The stapes is the smallest ossicle bone, and the smallest bone in the body—measuring about 3.2 millimeters (mm) in height, and 2.8 mm in width.
It has four major features:
The head of the stapes, connected to the incus at the incudostapedial joint, is round, and significantly smaller than the base. The anterior and posterior limbs curve away from the head symmetrically and attach to the oval-shaped base of the stapes, giving this bone the stirrup shape.
The tympanostapedial joint connects this bone to the oval window, which is the membrane that separates the middle ear from the cochlea. Notably, the stapes bone is also connected to the rear side of the malleus via the incudomalleolar joint.
The Function of the Auditory Ossicles
Anatomical Variations
Approximately one in 10,000 people are born with malformations or variations in ossicle structure.There are many different types of abnormalities, and they can affect one side (unilaterally) or both (bilaterally).
The stapes bone has the most variations of the three, while the incus has the least.These structural variations can have very serious, debilitating effects on hearing function.
Here are some of the variants:
The specialized structure of the ossicles allows soundwaves to be converted to electrical signals for your brain to process. How does this work? Here’s a quick breakdown:
Health conditions that involve the ossicles can seriously affect hearing.
The most common problem affecting the ossicles is ossicular chain discontinuity, in which the bones are either fused together with limited mobility or set too far apart.This inhibits vibrations of the eardrum from being translated to the oval window. This can lead to impaired hearing,tinnitus(a persistent ringing in the ears), or total deafness.
A number of conditions can lead to ossicular chain discontinuity or other issues of the ossicles, including:
Hearing loss, deafness, or other auditory problems can be debilitating. A number of treatments can correct or help manage these issues, including:
7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Rasuli B, Gaillard F.Middle ear ossicles. Radiopaedia.Osika A.Auditory ossicles. Kenhub.Hacking C, Gaillard F.Malleus. Radiopedia.Luijkx T, Gaillard F.Stapes. Radiopaedia.Luers J, Hüttenbrink K.Surgical anatomy and pathology of the middle ear.J Anat. 2015;228(2):338-353. doi:10.1111/joa.12389Saha R, Srimani P, Mazumdar A, Mazumdar S.Morphological variations of middle ear ossicles and its clinical implications.J Clin Diagn Res. 2017;11(1):1-4. doi:10.7860/jcdr/2017/23906.9147Kanona H, Virk J, Kumar G, Chawda S, Khalil S.A rare stapes abnormality.Case Rep Otolaryngol. 2015;2015:1-4. doi:10.1155/2015/387642
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Rasuli B, Gaillard F.Middle ear ossicles. Radiopaedia.Osika A.Auditory ossicles. Kenhub.Hacking C, Gaillard F.Malleus. Radiopedia.Luijkx T, Gaillard F.Stapes. Radiopaedia.Luers J, Hüttenbrink K.Surgical anatomy and pathology of the middle ear.J Anat. 2015;228(2):338-353. doi:10.1111/joa.12389Saha R, Srimani P, Mazumdar A, Mazumdar S.Morphological variations of middle ear ossicles and its clinical implications.J Clin Diagn Res. 2017;11(1):1-4. doi:10.7860/jcdr/2017/23906.9147Kanona H, Virk J, Kumar G, Chawda S, Khalil S.A rare stapes abnormality.Case Rep Otolaryngol. 2015;2015:1-4. doi:10.1155/2015/387642
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Rasuli B, Gaillard F.Middle ear ossicles. Radiopaedia.Osika A.Auditory ossicles. Kenhub.Hacking C, Gaillard F.Malleus. Radiopedia.Luijkx T, Gaillard F.Stapes. Radiopaedia.Luers J, Hüttenbrink K.Surgical anatomy and pathology of the middle ear.J Anat. 2015;228(2):338-353. doi:10.1111/joa.12389Saha R, Srimani P, Mazumdar A, Mazumdar S.Morphological variations of middle ear ossicles and its clinical implications.J Clin Diagn Res. 2017;11(1):1-4. doi:10.7860/jcdr/2017/23906.9147Kanona H, Virk J, Kumar G, Chawda S, Khalil S.A rare stapes abnormality.Case Rep Otolaryngol. 2015;2015:1-4. doi:10.1155/2015/387642
Rasuli B, Gaillard F.Middle ear ossicles. Radiopaedia.
Osika A.Auditory ossicles. Kenhub.
Hacking C, Gaillard F.Malleus. Radiopedia.
Luijkx T, Gaillard F.Stapes. Radiopaedia.
Luers J, Hüttenbrink K.Surgical anatomy and pathology of the middle ear.J Anat. 2015;228(2):338-353. doi:10.1111/joa.12389
Saha R, Srimani P, Mazumdar A, Mazumdar S.Morphological variations of middle ear ossicles and its clinical implications.J Clin Diagn Res. 2017;11(1):1-4. doi:10.7860/jcdr/2017/23906.9147
Kanona H, Virk J, Kumar G, Chawda S, Khalil S.A rare stapes abnormality.Case Rep Otolaryngol. 2015;2015:1-4. doi:10.1155/2015/387642
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