stapes

Bone: Stapes
A. Left stapes. B. Base of stapes, medial surface.
Chain of ossicles and their ligaments, seen from the front in a vertical, transverse section of the tympanum.
Malleus Tensor Tympani Incus Stapedius Labyrinth Stapes Auditory Canal Tympanic Membrane (Ear Drum) Eustachian Tube Tympanic cavity
Bones and muscles in the tympanic cavity in the middle ear
Gray's	subject #231 1045
Precursor	2nd branchial arch[1]
MeSH	Stapes

The stapes or stirrup is the stirrup-shaped small bone or ossicle in the middle ear which is attached to the incus laterally and to the fenestra ovalis, the "oval window" medially. The oval window is adjacent to the vestibule of the inner ear. The stapes 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.^[2]

In non-mammalian vertebrates, the bone homologous to the stapes is usually called the columella; however, in reptiles, either term may be used.

As the stapes first develops embryologically from the 6th to 8th week of life, it surrounds the stapedial artery, which supplies the majority of the vasculature of the embryonic head. After that period, the external carotid artery is generated and takes over for the stapedial artery, which subsequently involutes, leaving the stapes with a windowframe-like structure.

See also

• Bone terminology
• Terms for anatomical location
• Evolution_of_mammalian_auditory_ossicles

References

1. ^ hednk-023 — Embryology at UNC
2. ^ http://anatomy.med.umich.edu/nervous_system/ear_ans.html Stapedius muscle

• Vallejo-Valdezate LA, Martín-Gil J, José-Yacamán M, Martín-Gil FJ, Gil-Carcedo LM. "Scanning electron microscopy images and energy-dispersive X-ray microanalysis of the stapes in otosclerosis and van der Hoeve syndrome". Laryngoscope. 2000 Sep;110(9):1505-10.

External links

• http://web.archive.org/web/20061111030032/http://webpages.marshall.edu/~hurlburt/310lec13.html
• http://faculty.juniata.edu/yohn/reptilialab.htm
• http://research.meei.harvard.edu/otopathology/3dmodels/