Entrance to the antrum
Encyclopedia
The aditus to mastoid antrum (entrance or aperture to the mastoid antrum), also known as the otomastoid foramen, is a large irregular aperture, which leads backward from the epitympanic recess
into a considerable air space, named the tympanic or mastoid antrum
.
The antrum communicates behind and below with the mastoid air cells, which vary considerably in number, size, and form; the antrum and mastoid air cells are lined by mucous membrane
, continuous with that lining the tympanic cavity
.
On the medial wall of the entrance to the antrum is a rounded eminence, situated above and behind the prominence of the facial canal
; it corresponds with the position of the ampullated ends of the superior and lateral semicircular canals.
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 of the skull. Inflammation which has spread to the...
into a considerable air space, named the tympanic or mastoid antrum
Mastoid antrum
The mastoid antrum is a cavity in the petrous portion of the temporal bone, communicating posteriorly with the mastoid cells and anteriorly with the epitympanic recess of the middle ear via the aditus to mastoid antrum .-External links: - "Illustration of the continuity of the...
.
The antrum communicates behind and below with the mastoid air cells, which vary considerably in number, size, and form; the antrum and mastoid air cells are lined by mucous membrane
Mucous membrane
The mucous membranes are linings of mostly endodermal origin, covered in epithelium, which are involved in absorption and secretion. They line cavities that are exposed to the external environment and internal organs...
, continuous with that lining the tympanic cavity
Tympanic cavity
The tympanic cavity is a small cavity surrounding the bones of the middle ear.It is formed from the tubotympanic recess, an expansion of the first pharyngeal pouch....
.
On the medial wall of the entrance to the antrum is a rounded eminence, situated above and behind the prominence of the facial canal
Facial canal
The facial canal is a Z-shaped canal running through the temporal bone from the internal acoustic meatus to the stylomastoid foramen. In humans it is approximately 3 centimeters long, which makes it the longest human osseous canal of a nerve...
; it corresponds with the position of the ampullated ends of the superior and lateral semicircular canals.
External links
- Description at umich.edu
- http://www.dartmouth.edu/~humananatomy/figures/chapter_44/44-5.HTM