Head and neck anatomy- Trigeminal Nerve, exam 3 Flashcards
What is the V3 nerve?
mandibular
the mandibular nerve (V3) has 2 modalities which are
- somatic sensory: touch, temp, pain
- somatic motor: skeletal muscle movement
what are the 3 large branches of the trigeminal nerve?
- ophthalmic
- maxillary
- mandibular
the ophthalmic and maxillary are purely…
sensory
which branch of the trigeminal nerve is both sensory and motor
mandibular nerve
what is the front wall of the infratemporal fossa?
the maxilla
what is the ceiling of the infratemporal fossa?
the greater wing of the sphenoid
what is the ball for the modified ball and socket joint?
the condyle of the mandible
what is the socket for the modified ball and socket joint?
the glenoid fossa
where does the infratemporal fossa stop?
where the glenoid fossa of the socket for the TMJ starts
what is the medial boundary of the infratemporal fossa?
the lateral pterygoid plate
what is the space thats inside the the vertical part of the mandible?
the ramus between the maxilla and the lateral pterygoid plate
where does the infratemporal fossa stop?
the glenoid fossa
what is the largest hole that we’ll see in the sphenoid?
the foramen ovale
what is the foramen ovale?
- oval shape
- where V3 is going to exit
- largest hole in sphenoid
how does V3 exit the skull?
it comes out of the cranial cavity where the brain is and where the trigeminal ganglion is. V3 will then come down that opening and as soon as it gets to the Infratemporal fossa it will come out and immediately divide into all its branches.
where are all of the somatic sensory cell bodies for the trigeminal nerve
Trigeminal ganglion
where do the dural branches go?
goes to the meninges or connective tissue around the brain
what does the trigeminal ganglion supply?
dura that’s inside your parietal bone and temporal bone on the side of your skull
where does V3 exit?
the foramen ovale where all of its branches will be in the infratemporal fossa
Auriculotemporal n.
- goes posteriorly
- purely sensory
- goes right in front of the ear
what branch goes posteriorly and exits the infratemporal fossa?
the auriculotemporal n.
what kind of nerve is the auriculotemporal n.?
purely sensory
what does the auriculotemporal n. supply?
skin of the external ear, side of the head into the scalp, and skin above the external ear
what is the most important thing about the auriculotemporal n.?
it’s really important for people with TMJ problems
why is the auriculotemporal n. so important for people with TMJ problems?
because this nerve is the primary sensory innervation of the TMJ
what is the little branch that turns downward off the auriculotemporal n.?
it goes into the parotid salivary glands
- has NOTHING to do with the secretion of the glands
- carries sensory information from the gland
what cranial nerve makes the glands secrete?
glossopharyngeal
if somebody has a prodded gland tumor, or a little kid with mumps and their glands are swollen and painful, what nerve would case that?
the auriculotemporal nerve because it also carries sensory innervation to the prodded salivary gland
the auriculotemporal n. also has nerves that go into the…
the skin that lines your ear canal all the way to your eardrum( tympanic membrane)
Nn. to mm. of mastication
tend to be named to the muscle they go to
- 3 of them
what will you see immediately after coming through the foramen ovale
a lot of small nerves that are going to come out and be motor nerves that go to muscles of mastication
which nerve of mastication is a mixed nerve?
the inferior alveolar n.
Buccal n. (sometimes called the long buccal n.)
- purely sensory
- sensory nerve supply to buccal mucosa (cheek)
- has little branches that will cross the boundaries of vestibule to supply gingiva along molars and premolars
where is this gingival branch located?
important for anesthesia when working on mandibular teeth
- most anterior
Lingual n.
somatic sensation to the tongue, NOT taste
- temp
- pain
- touch
what else does the lingual n. supply?
- mucosa on the floor of the mouth underneath the tongue
- sublingual mucosa
- lingual gingiva for lower teeth
what part of the tongue is supplied through the lingual n.?
the anterior 2/3
is the buccal or lingual n. larger?
the lingual n.
inferior alveolar n.
most concerned about for anesthesia of the lower teeth due to this nerve being sensory to ALL of them
- mixed nerve
the inferior alveolar n. is going to tunnel through…
the mandibular foramen
the lingual nerve is always in the— of the inferior alveolar n.
front
N. to mylohyoid
- takes all of the motor fibers with it and everything that’s left is purely sensory that enters the mandible
all of the motor that is in the inferior alveolar n. comes off into the…
N. to mylohyoid
whatever goes into the mandible and runs through the mandibular foramen in the mandibular canal to reach the lower teeth is
purely sensory
what happens when the nerve to mylohyoid comes off of the back edge of the inferior alveolar nerve?
it takes all of the inferior alveolar nerves motor axons with it
the nerve to mylohyoid is the motor nerve supply to
our anterior set of super hyoid muscles
how is our suprahyoid muscles divided into?
an anterior set and a posterior set
where does the N. to mylohyoid go through?
the mandibular canal and sends apical branches that go up into the tip of the tooth roots to supply the teeth for sensation
anterior set of suprahyoid
- mylohyoid
- anterior digastric muscle
both supplied by the N. to mylohyoid
supplied by V3
what else does the N. to mylohyoid supply
supplies the buccal and lingual gingiva of lower teeth
Mental N.
doesn’t supply any teeth but supplies the lower lip/skin and crosses over to also supply some labial gingiva underneath the incisors
- full thickness of the lower lip
what part of the dermatome does the mental N. supply?
sensory innervation of the chin as a whole
the mental nerve doesn’t supply any teeth, just the skin and mucosa? T/F
true
the buccal nerve supplies the full thickness of the…
cheek along with sensation inside the mucosa ( touching cheek with your tongue )and outside the cheek( touching your cheek with your finger)
the muscles innervated by the mandibular nerve are all…
skeletal muscle
voluntary activated (use somatic sensation)
the mental nerve supplies the full thickness of the…
lower lip with sensation
what muscles of mastication are going to move the mandible with respect to the cranium so that you apply forces to food between the teeth?
- temporalis muscle
- masseter (superficial and deep)
- medial pterygoid
- lateral pterygoid( superior and inferior heads)
what type of nerve is the masseter nerve?
a mixed nerve because it has a little somatic sensory to i
what is the somatic sensory territory for the masseter going to be part of?
the TMJ
the auriculotemporal n. is the major nerve supply to the TMJ, whereas the n. to masseter is a — contributor
minor
other muscles that are supplied
- tensor tympani
- tensor veli palatini
- mylohyoid (suprahyoid muscle)
- anterior digastric (suprahyoid)
tensor tympani
muscle in the middle ear
Tensor Veli Palatini
muscle of the soft palate that is needed for swallowing
the nerve to mylohyoid does both the..
mylohyoid and the anterior digastric muscle
medial pterygoid (lateral picture)
floor of the space and all the V3 branches are in the infratemporal fossa, so all of these branches are above the medial pterygoid plate
auriculotemporal n.
- exits out the back of the infratemporal fossa
- purely sensory
- comes off of V3 and squeezes out behind the TMJ and then comes up onto the front of the ear and side of the head
Buccinator muscle
muscular wall of the cheek
buccal N. (lateral view)
the buccal nerve is coming down through the infratemporal fossa and comes through the muscles really high ( between the 2 heads of lateral pterygoid)
lingual N. (lateral view)
the floor of the infratemporal fossa and sits right on the medial pterygoid muscle
- purely sensory
the medial pterygoid is the — of
the infratemporal fossa
floor
chorda tymapni
- a branch of the facial nerve
- hearing things taste for the anterior 2/3 of tongue
how do we get taste into the anterior 2/3 of the tongue through chorda tympani?
it joins the back of the lingual nerve
an easy way for the facial nerve to send its taste fibers to the same part of the tongue is to hitchhike with a nerve that is already going there. T/F
true
the n. to mylohyoid always comes off of the
inferior alveolar nerve
the chorda tympani is always joining the
lingual nerve
pterygoid plexus of veins
a big venous plexus that is also occupying that space
pterygoid muscles and things like that, all the V3 branches in and around all that stuff is going to have a..
mesh or network of veins that are organized into a plexus
what is a plexus?
interconnecting lots of connections that are like a net rather than just a singular linear vessel
anytime you stick a needle into the infratemporal fossa, you are at risk of what
damaging the venous plexus
what happens when the venous plexus gets “damaged”
it bleeds and you’ll generally see a pt complain of :
- discomfort and swelling
- stiffness with opening and closing
this is from a hematoma (mass of blood) in their infratemporal fossa
light touch impulses go back and are interpreted in one part of the brain but pain and temperature go to a…
different nucleus in the brain
if you want to test the trigeminal nerve function completely you can’t just do touch. You have to do touch separately from pain and temperature. T/F
true
V1 testing
test skin above eyebrow
v2 testing
come down to the cheek under the lower eyelid
V3 test
- test skin or lower lip
- stay away from midline
what does the dural branch do
sensory to meninges (stays inside of head)
elevation
jaw closing
depression
opening
retrusion
position of the mandible posterior from the centric position as related to the maxilla
protrusion
sticking mandible out
Right lateral excursion
shifting mandible to the right
Left lateral excursion
shifting mandible to the left
temporalis insertion
coronoid process of mandible
temporalis origin
inferior temporal line
the brain uses parts of the temporalis muscle______
independently
independently
what is the function of the superior temporal line
attachment for connective tissue that covers the temporalis muscle
masseter origin
zygomatic arch
masseter insertion
lateral surface and angle of mandibular ramus
masseter muscle function
elevates mandible
temporalis muscle function
elevates mandible
what is the purpose of the temporalis fascia
it allows for greater strength of the temporalis muscle because muscle fibers of the temporalis muscle can attach here
which muscle is most complicating
masseter
which muscle is the most powerful closer
masseter
medial pterygoid muscle insertion
deep surface of the angle
medial pterygoid muscle origin
deep head: lateral pterygoid plate of sphenoid bone
superficial head: part of maxilla
parts of the medial pterygoid muscle
deep head and superficial head
medial pterygoid muscle function
elevates mandible
which muscle is the 2nd most powerful closer
medial pterygoid
Lateral pterygoid superior head origin
greater wing of sphenoid bone
lateral pterygoid superior head function
positions the articular disk in opening AND closing; helps avoid pinching of the joint capsule
lateral pterygoid superior head insertion
articular disc of TMJ
lateral pterygoid inferior head origin
lateral surface of lateral pterygoid plate
lateral pterygoid inferior head insertion
neck of mandible
lateral pterygoid inferior head function
pulls condyle forward and causes OPENING
which pterygoid muscle is more anterior
lateral
what is the one muscle that is an important opener
inferior head of lateral pterygoid
muscles ______ the mandible bone
sandwich
what are the 3 layers of cartilage in the TMJ
cartilage coating the depth of the glenoid fossa, cartilage coating the head of the mandible, and the articular disk
what kind of joint is the TMJ
synovial joint (ball and socket)
what is the function of the articular disk of the TMJ
shock absorber
what does the capsular ligament do
it is wrapped like a cone around the condyle and neck of mandible and it holds the joint together
what is the articular eminence
thick strong bone that is well adapted in handling forces
the ceiling of the fossa is ____
very thin
the TMJ joint is divided in to
upper and lower compartments by the articular disk
TMJ ligament
located on the lateral side of the joint and maintains the joint’s integrity. It also prevents backwards dislocation
sphenomandibular and stylomandibular ligament
Guiding ligaments to keep condyle, disc and temporal bone firmly opposed
what kind of forces are experienced by the TMJ
compressive
compressive force means
two surfaces are pressing together; for every action there is an equal and opposite reaction
what are the steps to opening the mouth
1) anterior posterior movement (translation) in the upper compartment
2) hinge movement (rotation) in the lower compartment
what are the sensory innervations for the TMJ
ariculotemporal: primary on the back and sides
masseterice nerve: secondary on the front
other nerves: deep temporal nerves and mandibular nerve
anterior jaw dislocation
Someone opens excessively wide which can happen after a long dental appointment. Condyle hops over the articular eminence. Most common!!
What could you palpate extra-orally after an anterior jaw dislocation
coronoid process
why is lateral excursion important
it helps create the normal lateral component of the chewing cycle
other types of jaw dislocations
superior: punch in chin with the mouth open
posterior: punch in chin
lateral: usually only with jaw fractures
if you activate the right inferior lateral pterygoid then…
the jaw moves left
if you activate the left inferior lateral pterygoid then…
then the jaw moves right
if a patient has a paralyzed lateral pterygoid then….
the chin will deviate to the same side of the paralyzed muscle when the mouth is opened
