The aditus to mastoid antrum (otomastoid foramen or entrance or aperture to the mastoid antrum) is a large irregular cavity that leads backward from the
epitympanic recess
The epitympanic recess is a hollow located on the superior/roof aspect of the middle ear.
Clinical significance
This recess is a possible route of spread of infection to the mastoid air cells located in the mastoid process of the temporal bone ...
into a considerable air space named the tympanic or
mastoid antrum
The mastoid antrum (tympanic antrum, antrum mastoideum, Valsalva's antrum) is an air space in the petrous portion of the temporal bone, communicating posteriorly with the mastoid cells and anteriorly with the epitympanic recess of the middle ear vi ...
.
The antrum communicates behind and below with the
mastoid air cells
The mastoid cells (also called air cells of Lenoir or mastoid cells of Lenoir) are air-filled cavities within the mastoid process of the temporal bone of the cranium. The mastoid cells are a form of skeletal pneumaticity. Infection in these cells ...
, which vary considerably in number, size, and form; the antrum and mastoid air cells are lined by
mucous membrane
A mucous membrane or mucosa is a membrane that lines various cavities in the body of an organism and covers the surface of internal organs. It consists of one or more layers of epithelial cells overlying a layer of loose connective tissue. It is ...
, continuous with that lining the
tympanic cavity
The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound.
Structure
On its lateral surface, it abuts the external auditory ...
.
On the medial wall of the entrance to the antrum is a rounded eminence, situated above and behind the prominence of the
facial canal
The facial canal (''canalis nervi facialis''), also known as the Fallopian canal, is a Z-shaped canal running through the temporal bone of the skull. It runs from the internal acoustic meatus to the stylomastoid foramen. It contains the facial n ...
; it corresponds with the position of the ampullated ends of the superior and
lateral semicircular canal
The semicircular canals or semicircular ducts are three semicircular, interconnected tubes located in the innermost part of each ear, the inner ear. The three canals are the horizontal, superior and posterior semicircular canals.
Structure
The ...
s.
See also
*
Aditus
*
Mastoid antrum
The mastoid antrum (tympanic antrum, antrum mastoideum, Valsalva's antrum) is an air space in the petrous portion of the temporal bone, communicating posteriorly with the mastoid cells and anteriorly with the epitympanic recess of the middle ear vi ...
*
Epitympanic recess
The epitympanic recess is a hollow located on the superior/roof aspect of the middle ear.
Clinical significance
This recess is a possible route of spread of infection to the mastoid air cells located in the mastoid process of the temporal bone ...
References
External links
Description at umich.edu* http://www.dartmouth.edu/~humananatomy/figures/chapter_44/44-5.HTM
Bones of the head and neck
Ear
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