oral cavity Flashcards
oral fissure
between lips - entry to the mouth
oral cavity
bounded laterally by cheeks and extends posteriorly to oropharyngeal isthmus
vestibule
space between lips/cheeks and upper and lower alveolar ridges/teeth
region of oral cavity
oral cavity proper
area medial to alveolar ridge
region of oral cavity
cutaneous innervation to cheeks
zygomaticofacial and infraorbital nerves (V2) buccal nerve (V3)
vascular supply to cheeks
branch of maxillary artery
vascular supply to lips
superior and inferior labial branches of facial artery
cutaneous innervation to lips
infraorbital nerve (V2) mental nerve (V3)
orbicularis oris
sphincteric-functioning muscle surrounding oral fissure
muscle of facial expression
CN VII
buccinator
muscle of the cheek
origin: pterygomandibular raphe
insertion: outer alveolar surfaces of maxilla and mandible
interdigitates with obicularis oris
prevents food from accumulating in vestibule
with tongue, keeps food between teeth during mastication
muscle of facial expression - CN VII
floor of mouth contents
lingual fenulum
sublingual papilla
sublingual folds
upper and lower labial frenulae
floor of mouth
horse-shoe shaped region between muscular diaphram and mobile portion of tongue
lingual frenulum
midline fold of mucosa going from the floor of the mouth to the interior surface of the tongue near its base
part of floor of mouth
sublingual papilla (caruncle)
opening of the submandibular salivary duct on each side of the lingual fernulum
part of floor of mouth
sublingual folds
mucosa overlying sublingual glands and submandibular ducts
extends posterolaterally from sublingual papilla
part of floor of mouth
upper and lower frenulae
part of floor of mouth
located in the vestibule
folds of mucosa attaching the lips to the gingiva in the median plane
muscles of floor of mouth
mylohyoid
geniohyoid
mylohyoid muscle
origin: mylohyoid lines of mandible
insertion: medially downwards on body of hyoid
interdigitate in midline raphe that extends from hyoid to symphysis menti
innervated by mylohyoid branch of inferior alveolar nerve
action: elevates floor of mouth at initiation of deglutination
depending on which bone if fixed, depresses mandible to open oral fissure or elevates hyoid during swallowing
geniohyoid muscles
deep to mylohyoid
medial and narrow
origin: inferior mental spines of mandible
insertion: body of hyoid
innervation: branch of C1 via hypoglossal nerve (XII)
action:
elevates and pulls hyoid bone anteriorly during swallowing
inferior mental spines
on mandible
insertion of geniohyoid muscle
midline raphe
where mylohyoid muscles intergiditate
extends from hyoid bone to symphysis menti
submandibular gland
located in digastric triangle superfuical to mylohyoid muscle
submandibular duct
loops around posterior free margin of mylohyoid muscle
continues anteriorly beneath mucosa of oral cavity proper
empties into sublingual papilla
sublingual papilla
small submucosal caruncle where submandibular duct empties into
drains into oral cavity proper
sublingual gland
on mylohyoid muscle
has numerous small excretory ducts that drain onto summit of sublingual fold
drain into oral cavity proper
autonomic innervation of head
all postganglionic parasympathetic fibers hitch a ride with one of the three branches of the trigeminal nerve
all postganglionic sympathetic fibers that go to specific targets hitch a ride on one of three branches of trigeminal nerve too
autonomic innervation to oral cavity
two preganglionic parasympathetic pathways
two preganglionic sympathetic pathways
parasympathetic innervation of head
III –> ciliary ganglion —> V1
VII —-> pterygopalatine ganglion —-> V2 (salivary glands sup to oral fissure)
VII —-> submandibular ganglion —-> V3 (salivary glands inf to oral fissure)
IX —–> otic ganglion —–> V3
autonomic innervation of major salivary glands
(not parotid)
parasympathetic:
1: superior to oral fissure via pterygopalatine ganglion
2: inferior to fissure via submandibular gland
sympathetic innervation:
1: superior to oral fissure via internal carotid vessels
2: inferior via external carotid vessels
autonomic innervation of minor salivary glands
superior to oral fissure via pterygopalatine ganglion
inferior to oral fissure via submandibular ganglion
parasympathetic innervation through pterygopalatine ganglion
VII (greater petrosal and deep petrosal; nerve of pterygoid canal) —–> pterygopalatine ganglion ——> V2 (glands: lacrimal, nose, palate and pharynx; zygomatic: communicating, lacrimal nerve; greater and lesser palatine nerves; nasopalatine and medial and lateral posterior nasal branches; pharyngeal nerve)
parasympathetic innervation through the submandibular ganglion
VII (chodra tympani; lingual (V3)) —-> submandibular ganglion —–> V3 (submandibular gland; sublingual gland; minor salivary glands of mouth (labial, lingual, buccal))
postganglionic sympathetic vasomotor innervation through pterygopalatine ganglion
internal carotid nerve, internal carotid plexus, superior cervical ganglion —-> deep petrosal nerve, nerve of pterygoid canal —-> pterygopalatine ganglion —-> distributed with branches of V2
postganglionic sympathetic vasomotor innervation through submandibular gland
superior cervical ganglion —-> plexus on external carotid and facial arteries —-> through submandibular gland —-> distributed with lingual branch of V3
functions of tongue
1: taste
2: speech
3: mastication
4: deglutition
5: absorption of medications
deep lingual veins
visible near the tip of the tongue just beneath the mucous membrane
absorb certain sublingual medications directly into the venous system
median sulcus
line on dorsum of tongue that divides it into lateral halves
terminates in foramen cecum
foramen cecum
pit at back/posterior of tongue where median sulcus terminates
embryologic origin of thryoglossal duct
sulcus terminalis radiates from here
sulcus terminalis
radiates obliquely anterior from foramen cecum
v-shaped groove that separates anterior 2/3 of tongue from posterior 1/3
oral portion of tongue
anterior 2/3
anterior to sulcus terminalis
pharyngeal portion of tongue
posterior 1/3 of tongue posterior to sulcus terminalis forms anterior wall of oropharynx devoid of papillae has submucosal lymphoid follicles = lingual tonsil
lingual tonsil
submucosal lymphoid follicles on pharyngeal portion of tongue
glossoepiglottic folds
mucosa of tongue is reflected onto epiglottis
lingual papillae
mucosal projections on dorsal surface of oral portion of tongue increase surface area 4 types: those that have taste buds: 1: fungiform 2: foliate 3: vallate those that don't 4: filiform
mucosal of inferior surface of tongue
stratified squamous epithelium without papillae or taste buds
muscles of tongue
all innervated by hypoglossal (XII) except palatoglossus (X) intrinsic: inferior longitudinal superior longitudinal transverse vertical extrinsic: genioglossus hyoglossus styloglossus palatoglossus
intrinsic muscles of the tongue
complex interlacing fasciculi allowing great mobility and alteration of shape important in deglutition and speech inferior longitudinal superior longitudinal transverse vertical
extrinsic muscles of tongue
originate from mandible, hyoid bone, styloid process and soft palate genioglossus hyoglossus styloglossus palatoglossus
genioglossus
extrinsic muscle of tongue
origin: superior mental tubercules of mandible: fans out superiorly and posteriorly
action: protrudes apex of the tongue
depresses central part of tongue - pulling mandible forward
prevents the tongue from sinking backwards and obstructing respiraton
hyoglossus
extrinsic muscle of the tongue
origin: greater horn of hyoid
insertion: ascends vertically to lateral portion of tongue
action: depresses tongue
styloglossus
extrinsic muscle of tongue
origin: styloid process
passes forward and downward
action: draws the tongue upward and backward
palatoglossus
extrinsic muscle of tongue
origin: palatine aponeurosis of the soft palate
descends in forward and lateral direction
action: elevates root of tongue
approxiamtes patatoglossal arches => shutting off oral cavity from orophayrnx during deglutination
embryological origin of tongue (arches)
1 (CN V)
3 (CN IX)
4 (CN X)
swellings that develop in development of tongue
1: paired lateral lingual swellings occur in ventral regions of 1st arch
2: 2 median unpaired swellings also occur - separated from each other by foramen cecum = tuberculum impar and hypobranchial eminence
tuberculum impar
swelling between 1st and 2nd arch
separated from hypotranchial eminence by foramen cecum
hypobranchial eminence
swelling in development of tongue
merges with the ventral parts of the 3rd and 4th arches
steps in development of tongue
4 weeks:
1: lateral lingual swellings develop from arch 1
tuberculum impar develops from arch 1 ust posterior to the lingual swellings
foramen cecum part of arch 2
hypobranchial eminence develops from arch iii
week 5:
2: lateral lingual swellings grow
copula = swelling in foramen cecum
merges with hypobranchial eminence
3: lingual swellings and tuberculum impar expand to form the anterior 2/3 of tongue
foramen cecum becomes really small and at cecum
sulcus terminalis = division between 1st and 3rd arch
3rd arch forms posterior 1/3 of tongue - overgrows 2nd arch and merges with 1st arch
embryological origin of anterior 2/3 of tongue
formed by expansion of lateral swellings (arch 1) with a minor contribution by tuberculum impar
embryological origin of posterior 1/3/root of tongue
formed by hypobranchial eminence with contributions from 3rd and 4th arches
embryological origin of musculature of tongue
migrates from occiptial myotomes and brings hypoglossal never (CN XII) with it
embryological origin of innervation of anterior tongue
general sensation: lingual nerve (branch of CN V3)
taste: chorda tympani (CN VII) is pretrematic - joins nerve of 1st arch (CN V3 - lingual branch)
embryological origin of innervation of posterior tongue
general sensation: glossopharyngeal nerves (CN IX)
taste: glossopharyngeal nerve (CN IX)
innervation of tongue (summary)
general sensation:
- anterior = lingual branch of mandibular (V3) - posterior = lingual branch of glossopharyngeal (IX)
special sensation (taste buds)
- anterior = VII - taste fibers travel back within lingual branch of mandibular nerve (V3) to chorda tympani to facial nerve (nervus intermedius - posterior = IX - lingual branch of glossopharyngeal
motor
- hypoglossal (XII) innervates all intrinsic and extrinsic muscles except palatoglossus (CN X)
path of nerves into tongue
lingual and hypoglossal (CN XII) enter from posterior aspect
pass between mylohyoid and hyoglossus
glossopharyngeal travels with lingual artery
enters oral cavity between constrictor muscle and hyoglossus muscle
path of lingual artery into tongue
enters oral cavity between deeper situated middle constrictor muscle and more superficial hyoglossus muscle
accompanied by glossopharyngeal nerve (CN IX)
lingual artery
branch of external carotid
main blood supply to floor of tongue
deep lingual veins
can absorb sublingual medication directlly into venous system
visible near tip of tongue just beneath mucous membrane
teeth
crown of tooth projects above gingiva
crown separated from root by neck
alveolus
bony socket into which the root of teeth are inserted
forms immovable gomphosis joint
gomphosis joint
joint between alveolus and teeth
immovable
labial/buccal surface
surface of teeth facing lip or cheek
lingual surface
surface of teeth facing tongue
periodontal ligaments
support teeth in alveolar socket
provide sensory info about tooth position and forces acting on teeth
sets of teeth
deciduous - 20: 2-1-2
- 2 incisors
- 1 canine
- 2 molars
permanent - 32: 2-1-2-3
- 2 incisors
- 1 canine
- 2 premolars
- 3 molarsnerve supply to teeth
braches of trigeminal nerve (CN V)
- trigeminal
- maxillary (V2)
- posterior superior alveolar nerve
- infraorbital nerve
- middle superior alveolar nerve
- anterior superior alveolar nerve
- mandibular nerve (V3)
- inferior alveolar nerve
arterial supply to teeth
maxillary artery
- posterior superior alveolar artery (upper jaw)
- infraorbital artery
- anterior superior alveolar artery (upper jaw)
- inferior alveolar arter (lower jaw)
superior alveolar nerves
posterior, middle and anterior
nerve supply to superior teeth
posterior is direct branch of maxillary (V2)
middle and anterior are branch of infraorbital, which is branch of V2
inferior alveolar nerve
nerve supply to lower teeth
branch of mandibular nerve (CN V3)
posterior superior alveolar artery
blood supply to upper jaw
direct branch of maxillary artery
anterior superior alveolar artery
blood supply to upper jaw
branch of infraorbital artery, which is branch of maxillary artery
inferior alveolar artery
blood supply to lower mandible
branch of maxillary artery
palate
partition between oral and nasal cavities
hard palate
anterior 2/3 of palate
palatine process of maxillary bones and horizontal plates of palatine bones
has incisive foramen and greater and lesser palatine foramen
thick oral mucosa with abundance of minor salivary glands
palatine process of maxillary bones
form anterior portions of hard palate
have incisive foramen and canal between the two lateral sides
incisive foramen and canal
between two palatine processes of maxillary bone
passageway between nasal cavities and oral cavity
behind the incisor teeth
horizontal plates of palatine bone
forms posterior portion of hard palate
contains greater and lesser palatine foramen
greater and lesser palatine canals and foramina
passageway between pterygopalatine fossa and hard and soft palates
in horizontal plate of palatine bone/hard palate
travel though perpendicular plate of palatine bone
pathway for pterygopalatine fossa to posterior portion of oral cavity proper and orophayrnx
perpendicular plate of palatine bone
makes up portion of posterior wall of lateral nasal cavity
greater and lesser palatine canals travel though
greater palatine canal
transmits descending palatine artery (origin of greater and lesser palatine arteries) and greater palatine nerve
descending palatine artery
origin of greater and lesser palatine arteries
travels through greater palatine canal to oral cavity proper and oropharynx
path of greater palatine nerve
travels through greater palatine canal
lesser palatine canal
transmits lesser palatine artery and lesser palatine nerve to soft palate
sphenopalatine foramen
medial exit from pterygopalatine fossa
transmits nerves and vessels from pterygopalatine fossa going to nasal cavity
greater palatine artery
branch of descending palatine artery
from greater palatine canal, travels anterior toward incisive canal
enters nasal cavity via incisive canal
anastamoses with branches of sphenopalatine artery
suplies blood to hard palate gums, mucosa, and glands
A dentist needs to extract an impacted third molar tooth in the right lower jaw. Where will he inject local anesthetic and which nerve will he hope to anesthetize?
In the area of the mandibular foramen and lingula on the medial side of the mandibular ramus.
The inferior alveolar nerve innervates the mandibular teeth.
If the anesthetic to the 3rd molar is effective, which muscle(s) may be paralyzed?
The mylohyoid and anterior belly of the digastric are both innervated by the nerve to the mylohyoid which branches off the inferior alveolar nerve just proximal to the mandibular foramen and creates the mylohyoid groove.
The patient notices that his right lower lip and chin have become numb after numbing of his third molar. How do you explain this?
These areas are innervated by the mental nerve, a terminal branch of the inferior alveolar nerve.
The patient also notices that the floor of his mouth has become numb after numbing of his third molar. His tongue feels “funny” and when he gently bit it to test it, it was also numb. Why?
The lingual nerve travels just slightly anteromedial to the inferior alveolar nerve in this area and is often also anesthetized by the diffusion of the anesthetic agent.
A patient had sensation to his 3rd molar numbed for a dental operation. Would his taste sensation on the right side of his tongue be affected? if so, where and why?
Yes, because special sense taste fibers from the taste buds on the anterior 2/3 of the tongue travel with the lingual nerve before transitioning to the chorda tympani on their way back to the facial nerve. Their cell bodies are located in the geniculate ganglion of the facial nerve. (Both taste and general sensation in the posterior 1/3 of the tongue travel in the glossopharyngeal nerve.)
The chorda tympani is not a branch of V3 but its fibers travel with the lingual nerve for the distal part of their course.
The patient has a tumor growing in his middle ear just anterior to the malleus. A CT scan shows it involving bone in that area. The floor of his mouth feels a little “gritty” on that side. What do you think is going on?
This is the area of the petrotympanic fissure where the chorda tympani exits the middle ear and enters the infratemporal fossa. This nerve carries preganglionic parasympathetic nerve fibers to the submandibular ganglion. The resulting decrease in saliva from submandibular, sublingual and microscopic salivary glands in the mucosa of the lower mouth might cause the “gritty” feeling.
he patient has a tumor growing in his middle ear just anterior to the malleus.
If you gave him a delicious lemon flavored hard candy to enjoy, where in his mouth would he suck on it?
On the left side where the taste fibers would not be affected.
To drain an abscess (a closed collection of pus) in the cheek area, an emergency room physician used local anesthesia for the surgery. Cutaneous branches of which nerve must be anesthetized to block pain sensation from the cheek area? buccal (V3) buccal (VII) inferior alveolar lingual mental
1
The buccal branch of CN V3 is sensory to the mucosa and skin in the area of the cheek.
The buccal branch of CN VII is motor to the buccinator muscle and other muscles of facial expression in that area.
A patient who experienced bilateral dislocation of the jaw (temporomandibular joints) could not swallow nor talk since the jaw would not elevate. Where are the condyles of the mandible located as a result of the dislocation?
1. against the external acoustic meatus2. against the anterior slope of the articular tubercle3. against the posterior slope of the articular tubercle4. in the mandibular fossa5. in the pterygoid fossa
2
To reduce the dislocation one needs to press the mandible posteroinferiorly so that the condyles can relocate posterior to the articular tubercles and move into the mandibular fossae.
Your patient has developed painful arthritis in her left TMJ. She is addicted to peanut M&M’s. Where in her mouth do you think she would chew them and why?
Right
Center
Left
I’ll stick with milkshakes
3
When chewing on the left side, the mandibular condyle would not be in the mandibular fossa. There would be less pressure in the joint and therefore less pain. Most of the pressure would be on the right TMJ, so she would choose the left side for chewing. In other words, if she chewed on the right side, there would be more pressure and pain on the left, so she would avoid that.
Inability to protrude the mandible indicates a dysfunction of which muscle?
Masseter
Lateral pterygoid
Medial pterygoid
Mylohyoid
2
Parasympathetic preganglionic nerve
fibers to the parotid gland travel in:
CN X
lesser petrosal nerve
CN VII
chorda tympani nerve
auriculotemporal nerve
2
Preganglionic parasympathetic efferent fibers branch from CN IX via the tympanic and then the lesser petrosal nerves to synapse in the otic ganglion. The postganglionic fibers then “hitch-hike a ride” on the auriculotemporal nerve to reach the parotid gland where they control glandular secretion.
The medial pterygoid muscle originates from: Parietal bone Occipital bone Sphenoid bone - lateral pterygoid plate Sphenoid bone - medial pterygoid plate Temporal bone
3
One of the functions of the medial and lateral pterygoid muscles is to produce the grinding action of the teeth when chewing. The muscles originate mainly from medial and lateral sides of the lateral pterygoid plate of the sphenoid bone respectively. From this picture you can appreciate that the medial pterygoids, acting independently can move the mandible from side-to-side laterally.
The sphenoid is bilaterally symmetrical and is a midline structure of the cranium. The anterior surface of the greater wing is in the orbit; the posterior surface is in the middle cranial fossa. The surface colored in yellow is essentially the posterior wall of the pterygopalatine fossa.
