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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 via the aditus to mastoid antrum (entrance to the mastoid antrum). These air spaces function as ...
The tympanic antrum is bounded above by a thin plate of bone, the tegmen tympani, which separates it from the middle fossa of the base of the skull, below by the mastoid process, laterally by the squama just below the temporal line, and medially by the lateral semicircular canal of the internal ear, which projects into its cavity.
Mastoid cells. The mastoid air cells vary greatly in number, shape, and size; they may be extensive or minimal or even absent. [1]: 746 The cells are typically interconnected and their walls lined by mucosa that is continuous with that of the mastoid antrum and tympanic cavity.
The mastoid process is the portion of the temporal bone of the skull that is behind the ear. The mastoid process contains open, air-containing spaces . [ 2 ] [ 3 ] Mastoiditis is usually caused by untreated acute otitis media (middle ear infection) and used to be a leading cause of child mortality.
The petrous part of the temporal bone is pyramid-shaped and is wedged in at the base of the skull between the sphenoid and occipital bones.Directed medially, forward, and a little upward, it presents a base, an apex, three surfaces, and three angles, and houses in its interior the components of the inner ear.
A third (pterotic) roofs in the tympanic cavity and antrum; while the fourth (epiotic) appears near the posterior semicircular canal and extends to form the mastoid process (Vrolik). The tympanic ring is an incomplete circle, in the concavity of which is a groove, the tympanic sulcus, for the attachment of the circumference of the eardrum ...
Koerner's septum is an anatomic boundary in the temporal bone formed by the petrosquamous suture between the petrous and squamosal portions of the mastoid air cells, at the anatomic level of the mastoid antrum. [1] Along with the middle ear ossicles, it is usually eroded in middle ear cholesteatomas. [2]
The aditus to mastoid antrum (otomastoid foramen) is a large, irregular opening [1] upon the posterior wall of the tympanic cavity by which the mastoid antrum (situated posteriorly) communicates with the epitympanic recess of the tympanic cavity (situated anteriorly). [2]