Case 4 anatomy Flashcards
petrous and what part of temporal bone?
squamous
what makes up the auricle?
made of elastic cartilage and covered by a layer or perichondrium and skin
external auditory meatus - bone or cartilage?
- The outer third is cartilaginous which, like the auricle, is covered by perichondrium and skin
- The inner two thirds are formed by bone covered by periosteum and skin
what produces ear wax?
ceruminous glands
which part of the tympanic membrane is pulled inwards by the tensor tympani muscle?
pars tensa
what are the different parts of the tympanic membrane?
- Umbo = the depression which marks the site of the handle of the malleus
- Pars flaccida = the thin part of membrane which is located superior to the lateral process of the malleus between the mallear folds
- Pars tensa = forms the majority of the membrane, it is pulled inwards by the tensor tympani muscle
- Anterior & posterior mallear folds = fibrous thickenings that extend from the lateral process of the malleus to the tympanic bone
what proivdes sensory innervation to the outer surface of the tympanic membrane? inner surface?
auricotemporal nerve (a branch of V3) with supplementation from the auricular branch of the vagus MANDIBULAR
Glossopharyngeal nerve provides sensory innervation to the internal surface of the tympanic membrane
what does the tympanic cavity consist of?
two parts; the tympanic cavity proper which lies medial to the tympanic membrane and the epitympanic recess that lies superior to the membrane
what connects the tympanic cavity and the mastoid air cells?
mastoid antrum
what forms the roof of the tympanic cavity?
tegmen tympani
(plate of thin bone (part of temporal bone)), separates the middle ear from the meninges & temporal lobe
what is the promontory?
formed by the basal turn of cochlear
where’s the carotid canal?
just anterior to the jugular foramen
what is the opening to the mastoid atrum called?
aditus
what’s in the anterior and posterior walls of the tympanic cavity?
anterior wall:
- opening of pharyngotympanic tube
- hole for tensor tympanic muscle
posterior wall:
- aditus for mastoid antrum
- pyramid for tendon of stapedius
where does the tensor tympani originate and insert?
originates from the auditory tube and attaches to the handle of malleus, pulling it medially when contracting
what innervates the tensor tympani muscle?
tensor tympani nerve, a branch of the mandibular nerve
what are the tensor tympani and chorda tympani branches of?
chorda tympani - facial nerve
tensor tympani - mandibular - trigeminal
where does the stapedius muscle originate and insert?
arises from the posterior wall of tympanic cavity and attaches on the stapes
what innervates the stapedius muscle?
facial nerve
what type of joints between the ossicles?
synovial
what is the purpose of the ear muscles?
damped down high frequency vibrations
what forms the eustachian tube?
posterolaterally the skeleton of the tube is formed by bone but the anterior two-thirds are cartilaginous
which muscles attach to the cartilaginous portion of the auditory tube? what do they do?
- levator veli palatini
- tensor veli palatini
they are actively involved in opening it
where are tubal tonsils found and what is there purpose?
under the mucosa that surrounds the opening of the auditory tube in the nasopharynx
to prevent infection spreading from the nasopharynx to the middle ear