Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
6 Cards in this Set
- Front
- Back
MIDDLE EAR
TYMPANIC MEMBRANE -fxn -"gaseous compression & rarefaction" -vibration of malleus |
6. Function
a. Sound consists of alternating waves of gaseous compression and rar- efaction; since compressed gas has a higher pressure than rarefied gas, alternating changes in air pressure cause the tympanic mem- brane to vibrate b. Vibration of the tympanic membrane vibrates the malleus, which, in turn, vibrates the incus and then the stapes; through the movements of the auditory ossicles, sound vibrations are transmitted from the tympanic membrane across the tympanic cavity to the fluid of the inner ear |
|
TYMPANIC CAVITY
-describe -roof |
B. Tympanic cavity
1. Slitlike, air-filled, mucosal-lined space medial to the tympanic membrane; contains the auditory ossicles 2. Roof: separates the tympanic cavity from the middle cranial fossa; com- posed of the tegmen tympani, a thin plate of the petrous part of the tem- poral bone |
|
TYMPANIC CAVITY
-floor |
B. Tympanic cavity
3. Floor: formed by the jugular fossa, a smooth depression roofing the jugu- lar foramen; the tympanic branch of the glossopharyngeal nerve arises below the jugular foramen, enters the external opening of the tympanic canaliculus between the carotid canal and jugular foramen, traverses the tympanic canaliculus, and emerges through the internal opening of the- tympanic canaliculus on the floor of the tympanic cavity |
|
TYMPANIC CAVITY
-anterior wall -"carotico-tympanic nerves" |
B. Tympanic cavity
4. Anterior wall a. Separates the tympanic cavity from the carotid canal; the carotico- tympanic nerves, postganglionic sympathetic fibers from the inter- nal carotid plexus, enter the tympanic cavity through its anterior wall |
|
TYMPANIC CAVITY
-anterior wall -"musculotubal canal" |
B. Tympanic cavity
4. Anterior wall b. Superiorly, the anterior wall presents the musculotubal canal, which is divided into two parallel semicanals by a thin, bony septum; the inferior semicanal represents the auditory tube, which connects the tympanic cavity to the nasopharynx, and the superior semicanal houses the tensor tympani muscle |
|
TYMPANIC CAVITY
ANTERIOR WALL -"cochleariform process" |
B. Tympanic cavity
4. Anterior wall c. The cochleariform process is formed by the pulleylike posterior end of the thin, bony septum separating the semicanals; over this process, the tendon of the tensor tympani bends laterally at a right angle to reach its insertion on the superior part of the manubrium of the malleus |