Nasal Cavity, Sinuses, and Ear Flashcards
What are the three parts of the ear?
external, middle and internal
What bone is most of the ear located within?
temporal bone (except most of the external ear)
What can the external ear be subdivided into?
the auricle (pinna) and the external acoustic meatus (EAM)
What is the function of the external ear?
gathers and modifies sounds, and then transmits sounds to the tympanic membrane (eardrum) via the external acoustic meatus.
Describe the external ear’s structure and capabilities.
a cartilaginous sound receptacle, capable of modifying sound by means of its shape, which can be altered by a series of extrinsic and intrinsic muscles controlled by the facial n.
Where does the EAM extend to and from?
approximately 2.5 cm from the concha of the auricle to the tympanic membrane
Which portion of the EAM is cartilaginous? What is the rest?
the proximal third is cartilaginous, the other 2/3 is osseous
What does the tympanic membrane separate?
external meatus from the tympanic cavity
What is the fibrous portion of the tympanic membrane associated with? What is it covered with medially and laterally?
tympanic plate of the temporal bone and is covered laterally by epidermis and medially by the mucous membrane of the middle ear
What is the larger portion of the tympanic membrane referred to as?
the tense part
What is the “flaccid” part of the tympanic membrane?
the anterosupeior corner
What is the flaccid part of the tympanic membrane bound by?
anterior and posterior mallear folds
How can you examine the tympanic membrane?
in vivo with an otoscope speculum
What is the middle ear?
The middle ear is mucosa-lined space within the petrous part of the temporal bone
What is the middle ear’s function?
The middle ear conducts sound energy from the tympanic membrane to the cochlea of the inner ear.
What three ossicles aid the middle ear in conducting sound from the tympanic membrane to the cochlea of the inner ear?
malleus, incus, & stapes
What are the surfaces of the tympanic cavity?
roof & floor, medial & lateral walls, and anterior & posterior walls
What structures is the roof of the tympanic cavity associated with?
canal for tensor tympani m. and
atticus - part of the tegmen tympani that attaches to incus & stapes
What is the roof of the tympanic cavity also referred as?
tegmen tympani
What is the floor of the tympanic cavity referred to as?
jugular wall
What structures is the floor of the tympanic cavity associated with?
tympanic canaliculus and accessory mastoid air cells
What structures is the medial wall of the tympanic cavity associated with?
from superior to inferior:
prominence of lateral semicircular canal (shared with posterior wall) =
facial prominence (shared with posterior wall) - bone outer border for facial canal =
oval window (fenestra vestibuli) - communication to vestibule of inner ear; receives footplate of stapes =
promontory & tympanic plexus =
round window (fenestra rotundum) - communication to cochlea; covered by a secondary tympanic membrane, which allows for cochlear fluid expansion
What structures is the posterior was of the tympanic cavity associated with?
entrance (aditus) to mastoid antrum - communication with the mastoid air cells =
prominence of lateral semicircular canal (shared with medial wall) =
facial prominence (shared with medial wall) - bone outer border for facial canal =
pyramidal eminence - contains the stapedius m. & transmits the tendon of stapedius m. anteriorly to the neck of the stapes =
opening for chorda tympani - from facial canal
What structures is the lateral wall of the tympanic cavity associated with?
tympanic membrane with manubrium of malleus attached - tensor tympani m. attached to manubrium of malleus
chorda tympani - surrounded by malleus (superolaterally), incus (superomedially), and tensor tympani m. (inferiorly)
What does the inner ear consist of, and what is it responsible for?
a bony apparatus lined by a series of membrane-lined bony passages which facilitate hearing and balance
How does the osseous tissue of the boney apparatus of the inner ear compare to that of the petrous of the temporal bone?
it is more dense
What is the central part of the bony apparatus referred to as?
the vestibule
What communications does the vestibule share with the inner ear?
the oval and round windows (fenestra vestibuli, and fenestra rotundum)
What is contained in the vestibule? What do they do?
vestibular sacs. They detect linear acceleration of the head to promote balance
What is the anteromedial portion of the bony apparatus referred to as? What is it shaped like? What does it do?
the cochlea : a snail shell : facilitates hearing
The parts of the bony apparatus include the vestibule, cochlea, and the ________________.
anterior, medial, and lateral semicircular canals
What are the semicircular canals responsible for?
the detect angular acceleration of the head to promote balance
Where are the external/internal ears in relation to the TMJ and oropharynx?
they are posterior to the TMJ and oropharynx
What two openings transfer nerves from the middle ear and TMJ?
the petrotympanic fissure, and the tympanic canaliculus
What does the petrotympanic fissure transmit?
the chorda tympani (preganglionic parasympathetic fibers from the facial n. bound for the submandibular ganglion)
What does the tympanic canaliculus transmit?
the tympanic n. (preganglionic parasympathetic fibers from the glossopharyngeal bound for the otic ganglion)
How does the middle ear communicate with the nasopharynx?
the pharyngotympanic tube
Where are the connections of the pharyngotympanic tube?
from the chamber of the middle ear, to the nasopharynx
What do the communications of the pharyngotympanic tube allow for?
equalization of pressure between the middle ear and nasopharynx and draining of materials from the middle ear
How can an inner ear infection occur? What is it called?
otitis media can be caused by pathogens ascending the pharyngotympanic tube and beyond.
Although the middle ear is an air-filled cavity, unlike the external auditory canal _____________________________.
it is not in direct contact with the external atmosphere
What do the ossicles of the middle ear form?
a chain of bones that transmit sound via vibration from the tympanic membrane to the oval window (receives footplate of stapes). Each connected by its own synovial joint to the next
What is the shape of the malleus
Hammer shaped (head, neck, and manubrium)
What is the manubrium of the malleus attached to?
the tympanic membrane
What muscle has an attachment on the malleus? Where?
the tensor tympani : the neck
What does the malleus articulate with? What part of the malleus does?
the incus : the head