Anatomy - Ear Flashcards
which bone is most important with regards to the ear
temporal bone
two parts of the temporal bone
squamous and petrous
name and articulations of thinnest part of the skull
pterion
- frontal, parietal, temporal and sphenoid bones
which nerves run within the temporal bone
CN VII/VIII
what prevents dislocation of TMJ
zygomatic process
which artery runs behind the pterion
middle meningeal
what is a feature of both the temporal and occipital bones
jugular foramen
what passes through the jugular foramen
CN IX, X, XI and internal jugular vein
bones of the anterior cranial fossa
frontal
ethmoid
sphenoid
bones of the middle cranial fossa
sphenoid
temporal (mainly this)
bones of the posterior cranial fossa
temporal
occipital (mainly this)
cranial nerves leaving in anterior fossa
CN 1
cranial nerves leaving in middle fossa
CN II, III, IV, Va, Vb, Vc, VI
cranial nerves leaving in posterior fossa
CN VII, VIII, IX, X, XI, XII
another name for auricle
pinna
contents of external ear
auricle to tympanic membrane via EAM
contents of middle ear
tympanic membrane to oval window and eustachian tube
contents of internal ear
oval window to internal acoustic meatus
function of external ear
collects and conveys sound waves to tympanic membrane
function of middle ear
amplifies and conducts sound waves to internal ear
function of internal ear
converts special sensory information to fluid waves then APs which are then conducted to the brain
type of cartilage at ear
elastic
contents of ear canal
EAM, 1/3 cartilage, 2/3 bony, lined with skin,
what produces earwax
ceruminous glands
name for folded over bit of external ear
helix
sensory supply to most of external ear, including lobe
anterior rami of C2/3 spinal nerves
sensory supply to inferior parts of EAM and tympanic membrane
vagus
sensory supply to superior parts of EAM and most of tympanic membrane
CN V3 (mandibular)
lymphatic drainage of lateral surface of superior half of ear
parotid nodes
lymphatic drainage of cranial surface of superior half of ear
mastoid nodes and deep cervical
lymphatic drainage of rest of auricle including lobe
superficial cervical lymph nodes
where does all lymph of ear eventually drain to
deep cervical lymph nodes in carotid sheath
thoracic duct/right lymphatic duct
venous angle
thin part of tympanic membrane seen superiorly on otoscope
pars flaccida
most inwardly depressed part of tympanic membrane
umbo
thick part of tympanic membrane seen posteroinferiorly
pars tensa
way to pull ear in child
posteroinferiorly
way to pull ear in adult
posteriosuperiorly
nerve supply to external surface of tympanic membrane
CN V3 (auriculotemporal branch)
nerve supply to internal surface of tympanic membrane
CN IX
sensory innervation of CN IX
middle ear cavity eustachian tube nasopharynx oropharynx tonsils
what does the eustachian tube connect
tympanic cavity to lateral wall of nasopharynx
sensory supply to laryngopharynx
CN X
close relation of opening of eustachain tube
adenoid tonsil
what pulls on the umbo to make the indentation of the tympanic membrane
handle of the malleus
what fits into the oval window
footplate of the stapes
what is the tympanic cavity proper
posterior to the tympanic membrane
what is the aditus
doorway into the antrum from the epitympanic recess
features of the facial nerve
special sensory, sensory, motor and parasympathetic
what is the chorda tympani
branch of the facial nerve which courses over the internal tympanic membrane and supplies the taste buds of the anteriror 2/3 of the tongue
also gives parasympathetic supply to the submandibular and sublingual salivary glands
base of skull foramen which facial nerve courses through
IAM and stylomastoid foramen
function of tensor tympani
dampens noise from chewing
function of stapedius
protects internal ear against excessive noise
nerve that chorda tympani courses with to supply taste
lingual nerve (branch of V3)
how to clinically test muscles of facial expression
frown, close eyes tightly, smile and puff out cheeks
what is the bony labyrinth
perilymph filled spaces inside otic capsule
features of perilymph
similar to extracellular fluid
features of endolymph
similar to intracellular fluid
fluid in semi-circular canal
endolymph
steps of sound transmission in the internal ear
- sound waves make tympanic membrane vibrate
- vibrations transmitted through ossicles
- base of stapes vibrates in oval window
- vibration of stapes creates pressure waves in perilymph
- hair cells in cochlea move, neurotransmitter released, AP stimulated and conveyed to brain via cochlear nerve
- pressure waves descend and become vibrations again
- pressure waves are dampened at round window
where do CN VII and VIII connect to the brainstem
junction between pons and medulla oblongata