Tympanic cavity

As the tympanic cavity ( cavum tympani ) is called the cavity of the middle ear, which contains the ossicles. It begins directly behind the eardrum and is ventilated by the Eustachian tube, which allows pressure equalization.

The tympanic cavity is about 12-15 mm long and 3-7 mm wide. My internal volume is low, only about 1 cm3. It consists of three sections:

  • Timpani dome ( epitympanum )
  • Timpani central space ( Mesotympanon )
  • Timpani Keller ( Hypotympanon )

Topographical Anatomy

Epitympanum ( Atticus / Atticus / epitympanic recess )

The epitympanum (other names are Atticus, Atticus and epitympanic recess ) is the uppermost portion of the tympanic cavity above the upper edge of the eardrum. Here the tympanic cavity is delimited at the top by a thin bone plate of the middle cranial fossa, which is referred to as tympanic roof ( tegmen tympani ). The epitympanum also contains the hammer head and the body of the incus and access to the mastoid ( aditus ad antrum ( mastoid ) ) - see also section mastoid temporal bone in the article.

The vascular supply of the epitympanum via the tympanic artery superior from the middle meningeal artery.

Mesotympanon

The Mesotympanon represents the central portion of the tympanic cavity. Its anatomic relationship to the adjacent structures describes one by his idealized limit to four walls:

  • Front Wall ( paries carotid tympani ): Behind her runs the internal carotid artery. In the caudal part of the wall, the eustachian tube opens into the tympanic cavity. About the tubal opening ( ostium tympanic tubae auditivae ) is the origin of the tympanic membrane tension muscle ( tensor tympani ).
  • Lateral wall ( paries membranaceus tympani ): it is almost exclusively formed by the eardrum.
  • Rear wall ( paries mastoid tympani ): It is bordered by the tympanic cavity to the mastoid bone ( mastoid process ) from back. In the superior - posterior region there is a connection to the pneumatic spaces of the mastoid ( aditus ad antrum ). At the level of the oval window ( fenestra ovalis ) you can make a pyramid -shaped projection, the pyramidalis eminence from which the stapedius muscle takes its output.
  • Mean wall ( paries labyrinthicus tympani ): It separates the worm ( cochlea) of the tympanic cavity. Between the oval window and the round window is called the sacral promontory. This small bump is caused by the lower turn of the cochlea.

The vascular supply to the area of the tube mouth is done via the posterior tympanic artery from the anterior maxillary artery and from the tympanic artery from the artery stylomastoidea for the rear portions of the tympanic cavity.

Hypotympanon

The Hypotympanon forms the lower part of the tympanic cavity. The lower wall ( paries jugularis tympani ) of the Hypotympanon borders the tympanic cavity to the internal jugular vein from back. The bone at this point is partially pneumatized and very thin.

The inferior tympanic artery from the ascending pharyngeal artery supplies the Hypotympanon.

Tympanic bladder

The tympanic bubble ( bulla ) is an enlarged bottom pocket of the tympanic cavity, which bulges the floor of the middle ear down. It usually occurs in people living in desert areas mammals and favors listening deeper tones. The size of the Sky, the vibrations of the eardrum condense these less and thus particularly deep tones are attenuated less. As low tones carry far, this adaptation is advantageous by listening over long distance for life in an open area.

152708
de