Special Sense Organs Part 4 Flashcards
T/F: The external acoustic meatus is about one inch in length and āSā shaped.
True
What bone contains the medial 2/3 of the external acoustic meatus?
temporal bone
T/F: the external acoustic meatus is covered by skin for its entire length and terminates at the chorda tympani.
False; terminates at the tympanic membrane
What is cerumen and what produces it?
earwax produced by modified sweat glands (not sebaceous glands)
How is otoscopic examination of the external acoustic canal made possible?
Because the canal is not straight, examination is possible by pulling out, down, and forward on the lobule (toward the chin)
What arteries supply the external ear?
posterior auricular branch of the external carotid artery, anterior auricular branch of the superficial temporal artery, and auricular branch from the occipital artery
What nerves supply sensory info to the external ear?
auriculotemporal nerve of the ophthalmic division of the trigeminal, auricular branch of the vagus, and great auricular nerve (C2 and C3)
What branches supply motor info to the external ear?
temporal and posterior auricular branches of the facial nerve
What ganglion provides sympathetics to the external ear?
superior cervical ganglion
What is the small space between the tympanic membrane and the inner ear?
middle ear
What two parts are recognized in the middle ear?
tympanic cavity and epitympanic recess
What are the 3 small bones found in the middle ear?
incus, malleus, and stapes
What 2 muscles are found in the tympanic cavity?
stapedius and tensor tympani
What forms the roof or tegmental wall of the middle ear?
petrous part of the temporal bone
A thin layer of bone separating the cavity of the middle ear from the internal jugular vein forms what boundary of the middle ear?
floor or jugular wall
A small opening in the jugular wall allows the entrance of what nerve?
tympanic branch of the glossopharyngeal nerve
T/F: the lateral or membranous wall of the middle ear is formed entirely by the tympanic membrane.
False; there is also a bony part of the lateral wall adjacent to the epitympanic recess.
T/F: the posterior or mastoid wall of the middle ear is incomplete.
True
What is the opening between the tympanic cavity and the mastoid air cells associated with the posterior (mastoid) wall?
the aditus of the mastoid antrum
What is the opening that the tendon of the stapedius muscle passes through in the posterior wall of the middle ear?
pyramidal eminence
T/F: there is an opening for the chorda tympani associated with the lateral wall of the middle ear?
False; posterior wall
What wall separates the middle ear cavity from the internal carotid artery?
carotid wall
What 3 openings exist in the carotid wall of the middle ear cavity?
a large opening for the pharyngotympanic tube, an opening for the tensor tympani to pass through, and a small opening for the chorda tympani to exit the cavity
What is the boundary between the middle ear and the inner ear?
labyrinthine or medial wall
What 5 landmarks are associated with the labyrinthine wall?
the promontory made by the cochlea, stapes attaches to the oval window, round window, prominence of the facial canal, and the lateral semicircular canal
What landmark of the labyrinthine wall is covered by a plexus formed by the tympanic branch of CN IX and branches from the internal carotid plexus? What is this plexus called?
the promontory, an impression made by the cochlea;
tympanic plexus
Mucous membranes of the middle ear, mastoid area, and pharyngotympanic tube are all supplied by what plexus?
tympanic plexus
What nerve leaves the tympanic plexus and travels to the otic ganglion?
lesser petrosal nerve
What landmark of the labyrinthine wall is an impression of bone formed by a canal conducting a major cranial nerve?
prominence of the facial canal (facial nerve)
What 3 very small bones are located in the tympanic cavity?
malleus, incus, and stapes
What is the largest of the middle ear bones which is in contact with the tympanic membrane?
malleus
What bone transmits vibrations from the 1st and 3rd bones of the middle ear?
incus
What bone of the middle ear is the 3rd bone? Its base sits against the oval window.
stapes
