sievert H&N infratemporal fossa Flashcards
what is the only trigeminal branch that has both motor and sensory?
V3
types of movements in the TMJ
gliding and hinge movements
list the GVEs
3 7 9 10
superior border of the infratemporal fossa
two ways to demarcate it
zygomatic arch in one sense.
in another sense,the infratemporal fossa is continuous to the temporal fossa, but it demarcated by the infratemporal ridge
what’s the inferior border of the infratemporal fossa?
infratemporal fossa is open to the neck….. but bounded somewhat by the inferior pterygoid muscle
so i guess you could say it’s the inferior pterygoid m.
anterior border of the infratemporal fossa
maxillary bone
medial border border of the infratemporal fossa
lateral pterygoid plate
lateral border of the infratemporal fossa
ramus of mandible
lateral border of the infratemporal fossa
parts of the temporal bone
body and ramus of mandible
and the angle too
body: the c-shaped part of the mandible that supports the teeth
ramus: the vertical extension of the mandible that is continuous w/ the body
angle: the area of the mandible between the body and the ramus. think of the body and ramus as little rectangles
coronoid process and condyle of mandible
coronoid process: anterior superior process of mandible
condyle: posterior superior process of mandible
landmark external acoustic meatus: name all the other temporal structures
anterior: zygomatic arch (condyle in between z-arch and ext. acoustic canal… but condyle is part of mandible)
inferior: styloid process
posterior: mastoid process
stylomastoid foramen
opening between styloid and mastoid…. facial nerve, CN7 passes through here to give off five terminal branches to muscles of facial expression…
not part of infratemporal fossa
location of medial ptyerygoid plate
just medial and deep to the lateral pterygoid plate
where do muscles of mastication attach?
medial or lateral side of pterygoid plate
body landmarks between the maxilla and the lateral pterygoid plate
pterygomaxillary fissure and pterygopalatine fossa
mandibular fossa
bony fossa just posterior to the zygomatic arch… serves as a fossa for the condyles of the madible
using styloid as a landmark (even tho it’s temporal), where is the position of the sphenoid bone landmarks of the infratemporal fossa?
all sphenoid:
closest to styloid, foramen spinosum, and then foramen ovale is a little bit more anterior and medial to the spinosum.
then you get the medial and lateral pterygoid plates
where does V3 exit the cranial cavity to enter the infratemporal fossa?
foramen ovale
middle meningeal artery enters through what foramen?
spinosum!
mandibular notch vs foramen
notch: the big space between the condyles and the coronoid process
foramen: where the vessels and nerves to the teeth go
TMJ joint cavities
superior and inferior joint cavities, separated by a mobile articular disc
TMJ surrounded by what?
strong capsule
bony part of the TMJ joint
mandibular fossa + articular tubercle (the most posterior protrusion of the zygomatic arch… most anterior bony part of TMJ)
and condyles of course
lateral pterygoid fxn in TMJ
attach to condyle and disc.
pull condyle and disc anteriorly
if you open your jaw really wide,
it rolls off anteriorly to the articular tubercle
hinge movements of TMJ
ELEVATION AND DEPRESSION
happens mainly in lower joint cavity
gliding movements of TMJ
protraction and retraction… happens in upper joint cavity
this makes sense coz the disc and the lower joint cavity are being pulled on forward by the lateral pterygoid m.
supporting structures of TMJ
- joint capsule: surrounds whole joint
- sphenomadibular lig
- stylomandibular lig
these last two ligs become taught during protraction
TMJ hyaline cartilage
surrounds the articular surfaces
synovial membrane of TMJ joint
lines the non weightbearing surfaces
what is inside the infratermporal fossa?
muscles of mastication
branches of mandibular n.
branches of maxillary art.
all muscles of masticaiton are innervated by?
CN 5
they come from the first arch
masseter
fxn
origin
insertion
powerful supericial muscle
helps w/ closure… teeny bit w/ protraction
o: maxillary bone and zygomatic arch
i: mandibular ramus
temporalis fxn
anterior fibers: closure only
posterior fibers: good retractors. do some closure too
masseteric n and art go thru?
what supplies the temporalis tho?
mandibular notch
ant. and post. deep temporal nerves
lateral pterygoid m.
fxn
o
i
fxn: powerful protraction
o: from lateral surface of pterygoid plate
i: condyle and articular disk of TMJ
medial pterygoid m.
fxn
o
i
Medial pterygoid muscle is similar to the masseter but on the inside of the jaw
o: it arises from the medial surface of the lateral pterygoid plate and part of the fossa between medial and lateral pterygoid plates
inserts on medial border of ramus and angle of mandible
sphenomandibular lig relative to muscles
runs straight down, in between lateral pterygoid m and medial pterygoid m
both pterygoid muscles arise from?
lateral pterygoid palte
parotid opens through?
buccinator
buccal branch of CN 5 vs CN 7 in terms of buccinator
buccal branch of 5 passes through to give sensory innervation to oral cavity
buccal of 7 innervates the buccinator, as it is a branchiomotor to facial expression
three nerves around lateral pterygoid
deep: lingual and infeiror alveolar
super
superficial: buccal branch of 5.
two immediate branches of the external carotid
superficial temporal and the maxillary artery
terminal branch of maxillary artery enters through?
pterygomaxilalary fissure and heads up to paterygopalatine fossa
branches of maxillary artery from origin to terminal part
- -Middle meningeal goes through foramen spinosum
- -Inferior alveolar artery travels with inferior alveolar nerve through the mandibular foramen to supply the teeth
- -2 deep temporal arteries travel superiorly and deep to the temporalis muscle (anterior and posterior branches to temporalis muscle)
- terminal brach that entered the pterygopalatine fossa
middle meningeal:
how did it get into skull?
fxn?
got in through foramen spinosum!!, which is slightly more lateral than foramen ovale
Middle meningeal artery supplies the dura
can be easily
torn following head trauma to the region of the temporal bone
structures near or in fossa that need somatosenosry innervation
teeth (we only are about lower law coz maxillary div nerve will go to upper jaw)
tongue
oral cavity
skin anterior to ear
tongue innervation
general sense: anterior by 5. posterior of tongue by CN 9.
special sense: taste by branhch of seven that jumps on five
in the undivided trunk of V3, three branches are motor but one is sensory
sensory=meningeal
motor=medial pterygoid, tensor veli palatini, tensor tympani
MMTT
in anterior branch of V3, four are motor, but one is sensory
sensory=buccal
motor = lateral pterygoid; masseteric n; anterior and deep terporal
BL MAP. big lickin map
mostly sensory, but one mixed
ALI
auriculotemporal = sensory
lingual = sensory
inferior alveolar = sensory but its branch to the mylohyoid is motor
tensory tympani fxn
dampen effect of sound on tympanic membrane and inner ear
tensory veli palatini fxn
open middle ear
lingual n fxn
carries sensory to 2/3 of tongue from CN 5, but also carries taste from CN7
inferior alveolar n fxn
Inferior alveolar is gonna supply teeth, but there is a single moddle branch called the mylohyoid nerve that comes off the alveolar—the myohyloid muscle.
structural etiology of motor fxn of cn 5
motor stuff: motor nucleus of CN 5—> motor root of CN 5 —> short distance —> trigeminal ganglion of CN 5
sensory
structural etiology of senosry info of trigeminal nuclues
- discriminative touch, two point discrimination, goes to chief sensory nucleus
- proprioception goes to mesencephalic nucleus (actually a ganglion)
- pain and temperature goes to spinal V nucleus
location of chief sensory 5 and motor V
mid pons
mesenphalic (up on midbrain… proprioception!) and spinal part (on medulla… pain and temp)
what’s weird about unconcious proprioception to the CN 5?
no true ganglia… remember these enter the mesencephalic nucleus… lots of times this nuclues will communicate w/ motor 5 to do reflexes
inferior alveolar n exits the mental foramen to to become?
mental nerve!
rule of one exception regarding glands
all the glands in the head are innervated by CN SEVEN—except for the parotid which is by nine.
two types of parasymp that enter ITF?
7 for the submandibular + sublingual glands
and 9 for the parotid
parasympathetics to the head leave brainstem w/ what cranial nerves?
3 7 and 9… ten too but not for head
shortly after exiting w/ cranial nerve, they’ll hitchhike to their targets on a branch of 5
brainstem locations of cn 3 7 and 9
3 midbrain
7pons
9medulla
chorda tympani kinds of fibers
-comes from CN 7 and has two kinds of fibers–SVA taste and parasympathetics to submandibular and sublingual glands
chorda tympani parasymp course
-cn 7 —> travel out of petrotympanic fissure —> jump on back of lingual nerve —> only the parasymp fibers will detour on the SUBMANDIBULAR ganglia to give to the submandibular gland —> then they’ll come back onto the lingual after their little loop around the submandibular ganglion—> then they’ll travel down onto lingual till they reach the sublingual gland —> FIN for the parasymps
chorda tympani taste SVA fibers course
cn 7 —> travel out of petrotympanic fissure —> jump on back of lingual nerve —> travel straight down to innervate the posterior two thirds of the tongue
petrotympanic fissure location
crack just posterior to the mandibular fossa
so close to it coz it looks like the condyle of the mandible will crush it.
course of chorda tympani through the middle ear
under the long limb of incus, over the handle of the malleus, and behind the tympanic membrane
where do the taste fibers of CN 7 dump in?
not pons….
they go down to the tractus solitarius to the NUCLEUS solitarius in the medulla
also all special visceral will go this way
where does cn 7 enter the brainstem?
near the pontomedullary junction. remember that pyramids end where pons begin
all the GVA or SVA info will travel down the tractus solitarius to enter the nucleus solitarius
CN 7 doesn’t do any GSA
why does branchiomotor nucleus of seven travel strangely?
It doesn’t just go into the pons normally.
it hooks over the top of CN 7 and then it does a big ol loop around back to where you’d think it be. branchiomotor nuclues hooking over probably is the cause for the branchiomotor migration
course of the CN 7 back to the brain
enter temporal bone through internal acoustic meatus
what innervates the parotid gland?
preganglionic parasymp from the lesser petrosal n (branch of glossopharyngeal, CN 9) will jump onto the V3 part of the trigeminal ganglion and travel down.
the only thing carried by lesser petrosal is preganglionic parasymp.
at otic ganglia, the postganglionic fibers will hitchhike w/ the auriculotemporal n from V3.
SECRETOMOTOR to parotid
where does CN IX enter or leave the brainstem?
nucleus ambiguus, which is the branchiomotor nucleus for 9 and 10 and 11 if we count it as branchiomotor
inferior salivatory nuclues
right next to nuclues anbigius. it’s visceromotor and gives rise to the presympathetic preganglionics that eventually will innervate the parotid
remember these come from CN 9
superior salivatory nucleus
adjacent to the branchiomotor nucleus, and it does the parasympathetics to CN 7
what exits over thru the jugular foramen?
9 10 and 11
course of tympanic n
cn 9 —-> exit skull thru jugular foramen —-> enter back into skull thru TYMPANIC CANALICULUS OPENING —> innervate tympanic plexus, providing GSA to middle ear, rests on tympanic promontory
route of lesser petrosal in relation to tympanic plexus
from tympanic plexus, preganglionic parasympathetic fibers will be given off —-> these will travel on the petrous portion of the temporal bone and then exit through the foramen ovale w/ the V3 and then go to parotid
course of auriculotemporal n
off posterior div of V3, wraps around middle meningeal artery, and then goes up toward carotid region and then just goes up over temporal n
