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Scribe: Laura Adams
Thursday, March 19, 2009
Proof: Brittney Wise
Dr. Tubbs
The Oral Cavity
Page 1 of 6
I. The Oral Cavity [S1]:
a. Let’s start with a simple definition. People call it the mouth, which is a very simplistic way to think about it.
II. Vestibule vs Oral Cavity Proper [S2]:
a. The oral cavity can be divided into the oral cavity proper, which is everything that is internal to your teeth, and a
vestibule which is every thing between the teeth and the lips/gums.
III. [S3]
a. This is an axial cut. As we progress we will learn the borders of the oral cavity. You’ll see that naturally the
tongue takes up most of the contents of the oral cavity. Without the tongue it would be a much more captious
region.
IV. Teeth [S4]
a. The teeth are 32 in the adult, less in the non-adult. Before the permanent teeth, there are 20 milk
teeth/deciduous/baby teeth.
b. In the adult, however if you look at the maxillary (top) and mandibular teeth, you will find that you have Medial
and lateral incisors. These are copied from top to bottom. You have a canine, a sharp pointed tooth. And you
have 2 premolars and 3 molars.
V. Picture of deciduous teeth [S5]
a. This shows you a section illustrating some of your deciduous teeth. The permanent teeth are below and haven’t
erupted yet.
VI. Tooth Innervation [S6]
a. For the mandibular teeth all of them receive innervations via the inferior alveolar and a little literature states
after anesthetizing the inferior alveolar some sensation remains in the mandibular teeth. It is thought in these
cases that some sensation may come from the nerve to the mylohyoid.
b. For the superior teeth, (the teeth in the upper jaw bone or the maxillary teeth), are innervated by the superior
alveolar nerves (anterior, middle, posterior). The anterior and middle come off the infraorbital and the posterior
arises before the nerve becomes the infraorbital so it comes from V2 or the maxillary nerve.
VII. [S7]
a. Quick clinical picture: this shows that anesthesia of all the lower teeth, on one side anyway, can be
accomplished by knocking out the nerve supply at the inferior alveolar nerve. This is done by palpating the
lingula and just beside that you will find the entrance into the mandibular canal and the inferior alveolar nerve.
VIII. The gingiva [S8]
a. The soft mucosa lining that is continuous with the mucosal lining of the cheek this is a coronal section. So you
should see buccinator muscle and the tongue in cross section. The gingiva helps solidify the connection
between the tooth and the bone that it is associated with, mandible in this case. It runs around the tooth and
done the lingual surface.
b. There is a difference in the innervations of the so called buccal side of the gingival verses the lingual side for top
and bottom teeth.
IX. Gingival innervations [S9]
a. Maxillary buccal (in the vestibule) = superior alveolars / infraorbital
b. Maxillary lingual surface that is internal to the teeth is greater palatine and nasopalatine especially anteriorly.
c. Mandibular buccal (external to the teeth) is from buccal branch of V3 (the long buccal nerve) and the mental
nerve which is one of the terminal branches of the inferior alveolar nerve.
d. Mandibular lingual surface (internal to the teeth) is all from the lingual nerve of V3.
X. Oral Cavity Roof: Hard/Soft Palate [S10]
a. Now we will look at some of the boundaries of the oral cavity. The roof, which if we remove the
mucoperiosteum, we see the boney structures. This picture shows the maxillary teeth.
b. We have the hard palate, which is know is composed mostly maxillary bone and the horizontal segment of the
palatine bone. You will see various sutures such as the intermaxillary suture, and it is along this suture that you
have palatoscesis or split palate that you will have disjunction or disarticulation between those 2 palatal shelves.
c. In the palatine bone you’ll see the greater and lesser palatine foramens, for the respective neurovascular
structures (greater and lesser palatine nerves, veins, and arteries). You also have incisive foramen.
d. Posterior nasal spine, remember from Salter’s lecture, that is the main attachment for the muscle inside the
uvula, the midline structure from the soft palate posteriorly.
XI. Diagram of the muscles [S11]
a. If we look at the junction between the soft and the hard palate, we have removed the mucoperiosteum. The soft
palate attaches along the posterior edge of the palatine bone.
b. The 2 prominent muscles of the soft palate are the tensor veli palatine (coming around the hamulus) and the
levator veli palatine. Other muscles associated with the soft palate are the uvularis (musculi uvuli). Notice the
relationship of the tensor veli palatine and the levator veli palatine to the eustachian tube.
Gross: 8:00 - 9:00
Scribe: Laura Adams
Thursday, March 19, 2009
Proof: Brittney Wise
Dr. Tubbs
The Oral Cavity
Page 2 of 6
XII. Gag Reflex [S5]
a. Here is a picture of the uvula in vivo.
b. The posterior portion of the oral cavity or the oropharynx. In any routine exam you look for the position of the
uvula. You want the uvula to keep a midline position, when you ask the patient to phonate (speak). You can
see some associations of that uvula with the soft palate for example if we follow the soft palate over we see the
palatopharyngeal arch and palatoglossal arch, which is more anteriorly located. And in between these 2 arches
is the palatine tonsil. In this person, most likely older, is is somewhat atrophied. To see this you really have to
depress the tongue.
c. The gag reflex is an important reflex in keeping things out of the oropharynx that don’t belong there. For
example, the uvula and associated soft tissues of the soft palate are extremely sensitive to touch, some people
more than others. If you put a finger or tongue depressor back there it illicits a gag reflex.
d. This reflex simply has a sensory limb from the glosspharyngeal nerve and a motor limb that contracts those
pharyngeal muscles from the vagus nerve and specifically its pharyngeal branches. So when you test
someone’s gag reflex you are testing both their IX and X cranial nerves.
XIII. [S13]
a. Now if somebody has a problem with their X cranial nerve or especially its source from the brainstem (nucleus
ambiguous) you will see something of this sort. So if the right vagus nerve of pharyngeal plexus is disrupted,
you’ll see that the right side of the soft palate is a little more inferiorly located and the tip of the uvula with such a
gag reflex will point to the contralateral side (away from the side of the lesion).
XIV.
Hard/soft palate Sensory/Motor Innervation [S14]
a. The muscles of the soft palate are innervated form the pharyngeal branch of X. With the exception of the tensor
veli palatine which gets its innervations from V3. Sensory and autonomic are carried in the greater and lesser
palatine nerves. Remember the greater travels anteriorly and the lesser travel posteriorly covering the soft
palate. If you burn the roof of your mouth, you’re stimulating the greater palatine nerve most likely.
XV. Oral Cavity Floor [S15]
a. If you press on the submandibular region and push up, you actually pressing the mylohyoid muscle (thin
muscle) and just beyond that is the tongue. So there is not a lot of tissue between the external surface and the
mylohyoid. So if the mylohyoid is deinnervated from an injury and you depress the tongue, you can see a bulge
coming out of the submandibular region which is just the tongue coming down.
XVI.
Oral Cavity Floor [S16]
a. So there’s the mylohyoid reflected and we have another smaller, closer to the midline muscle called the
geniohyoid. It attaches to the mandible from the genial spines (superior and inferior) and it specifically arises
from the inferior genial spine.
b. Genial refers to the mental region.
XVII. [S17]
a. Now this is a beautiful internal view of that same floor. Most of the tongue has been removed. We are looking
from the inside out toward the mandibular teeth (or what’s left of them.) We see the geniohyoid muscle.
b. This is the genioglossus, which is an extrinsic tongue muscle. The tongue is basically a grouping of several
skeletal muscles. They have several different attachments one coming from the mandible, the genioglossus.
c. We have cut the tongue out and we see the mylohyoid that extends from molars to the molars on the other side
(that is what “mylo” is referring to.) The geniohyoid is more in the midline. This muscle was mentioned when
we learned the suprahyoid muscles, and the geniohyoid receives its innervations from C1 fibers which
hitchhiked along with XII to get there.
d. If you can get this slide in your mind it really helps you with orientation in the lab. The following are other
features he said to study on your own: Glossoepiglottic folds, Lingual artery, Facial artery, Digastrics,
Stylohyoid, and Middle constrictor
XVIII. [S18]
a. This shows the floor again. This is sometimes referred to as the oral diaphragm. So we have thoraco-abdomial
diagram, a peritoneal diagram, and oral diagram to name a few.
b. Geniohyoid in the midline, and the mylohyoid.
c. We also see our smaller salivary glands, the sublingual gland and our submandibular gland (which remember
has a superficial and deep component.)
XIX.
[S19]
a. Here is a Germanic view of the geniohyoid muscle. “Germanic” because it was copied from an older German
atlas.
b. SQ: what has been cut off at the top near the incisors?
c. Answer: the genioglossus, the genio-tubercles in the front (superior and inferior) give rise to the genioglossus,
the superiors and inferiors, and the geniohyoid. So if you cut the tongue out by necessity you cut through the
genioglossus.
Gross: 8:00 - 9:00
Scribe: Laura Adams
Thursday, March 19, 2009
Proof: Brittney Wise
Dr. Tubbs
The Oral Cavity
Page 3 of 6
XX. Oral Cavity Lateral Wall [S20]
a. If we exclude the mucosa, and any fascia that may be lateral to this muscle – the buccinator. We have seen this
in the face, but you may be able to see it from the internal perspective. Posteriorly, the buccinator has an
attachment into the pterygomandibular raphe, a connective tissue line, and the muscle that is continuous with
that posteriorly is the superior pharyngeal constrictor.
XXI.
[S21]
a. Buccinator muscle is a muscle of facial expression, although it doesn’t give you much expression. Some people
include it as an accessory masticating muscle although it is not innervated by the trigeminal nerve. The
accessory masticatory component is that when this muscle becomes tense, it aligns food so that it maintains the
food between the molars. It you lose this tensity in the buccinator you might complain that you food ends up in
the vestibule when you are trying to chew.
XXII. Posterior Border: Fauces [S22]
a. We see the opening into the oropharynx and what is called the fauces, which literally means throat. From this
perspective as I showed you earlier, we see the uvula, the 2 tonsilar pillars (palatoglossal and the
palatopharyngeal folds and their associated muscles.)
b. So as you go from the oral cavity and start to move posteriorly you’ll move into the oropharynx.
XXIII. Anterior border: Lips [S23]
a. Anteriorly, we have the lips. This is a sagittal section. We see the mandible, tongue and lip. It is comes of the
mucosal lining (the skin) and the skeletal muscle. They function in grasping, sucking, speech, and osculation
(kissing).
b. Sensory innervations are from the superior labial from infraorbital nerve to the upper lip, and the inferior labial
from mental nerve to the lower lip. Inferior alveolar nerve block causes the skin of the lower lip to be numb.
XXIV. Philtrum [S24]
a. The midline furrow below the nose above the lip. It means “to love”. The Greeks thought this was a very
erogenous part of the body.
b. In more modern times, so in 15/16th century Europe where people didn’t bath, people began to smell other
people or themselves. They would place perfume on the philtrum to block out the bad smell.
XXV. Salivary Glands [S25]
a. We talked about the parotid gland. We saw that it has to take the saliva they make and drain it into the oral
cavity via a duct. So each gland has a duct associated with it. The parotid gland is in the paraotic region. The
sublingual and submandibular glands we see in the oral cavity, the sublingual gland entirely and submandibular
partially (the superficial, larger portion resides at the edge of the mandible. If you stimulate it you will feel saliva
pooling in your mouth.)
XXVI. [S26]
a. These glands may seem small but they can produce up to a 1 pint/day. Some people have trouble with their
lower lips because of a injury from a stroke or cerebral palsy. If you don’t have the lower lip then you tend to
droll saliva from the oral cavity.
b. One treatment for these patients is to remove some of the salivary glands. Now the parotid gland is difficult
because of the facial nerve, the lingual gland is hard to get to, but the submandibular gland is easy to get to (the
majority of it is superficial). You will often see an incision below the mandible on stroke and CP patients, where
a large part of the submandibular gland has been removed.
c. Innervation is fairly straight forward. The glosspharyngeal nerve innervates the parotid gland via the otic
ganglia. The submandibular and sublingual glands are innervated by the facial nerve to the submandibular
ganglia.
d. 7th nerve palsy, or bell’s palsy, would cause dry mouth.
XXVII. [S27]
a. Remember that the termination of these ducts are into the oral cavity.
b. Stenson’s duct, or parotid duct, was by the 2nd upper molar. That site is also a common location for a stone that
develops in the salivary tubes. Patients may present with swelling around the ear and you may find that they
simply have a little stone that is lodged in the opening of the parotid duct. This causes the saliva to build up into
the parotid gland. Remove the stone and the swelling goes away.
XXVIII. [S28]
a. The opening of the submandibular duct and the sublingual ducts are right below the front of the tongue.
b. Submandibular duct openings are on the sides of the frenulum, which is the midline tether.
c. So people are born with frenulum that is too taut, this is causes tongue-tied or ankyloglossus. So simply cut this
frenum to allow proper movement.
Gross: 8:00 - 9:00
Scribe: Laura Adams
Thursday, March 19, 2009
Proof: Brittney Wise
Dr. Tubbs
The Oral Cavity
Page 4 of 6
XXIX. [S29]
a. We will go on and look at a very nice view of the sublingual and submandibular glands. We notice this Cshaped submandibular gland. The superficial part we saw earlier when we did the suprahyoid region and then
the “tail” region that courses superior and on top of the mylohyoid muscle.
b. The submandibular duct proceeds anteriorly to open on either side of the frenulum.
c. The sublingual glands sit entirely superficial, or superior to the mylohyoid. Some of its drainage may be into the
submandibular duct and it has little individual ductlets that may drain directly into the oral cavity.
d. Another name for the submandibular duct is the duct of Wharton and another name for the accessory ducts from
the sublingual is _____? [Inaudible]
e. Look at the relationship between the lingual nerve and the submandibular duct which proceeds from a posterior
to anterior direction. Lingual nerve will come down into the oral cavity from V3 and will cross that submandibular
duct on its lateral service and also on its medial surface. As it enters the oral cavity just at the edge of the
mylohyoid, look at the relationship between the nerve and the third molar.
f. A third molar extraction can cause injury to the lingual nerve because of an intimate relationship between the
roots and the nerve. This can cause lose of touch and taste in the anterior 2/3 of the tongue because the corda
tympani has already become involved with this nerve.
XXX. [S30]
a. This is a older picture but it shows you the little accessory sublingual ducts stringing directly into the oral cavity.
b. It shows you a nice relationships between the lingual nerve, how it crosses the submandibular duct (on the
lateral and medial surface) and look at the opening of Stenson’s duct (parotid duct) just adjacent to the 2 nd
maxillary molar.
XXXI. Accessory Salivary Glands [S31]
a. In addition to the 3 major glands, you have a lot of accessory glands, located in the palate, lips, cheeks, around
the tonsils, and around the tongue. If we de-glove the face, take off the muscles of facial expression, you would
see a smattering of accessory salivary glands.
XXXII. [S32]
a. This shows you a nice collection of palatal salivary glands, in the hard and soft palate.
XXXIII. Submandibular ganglion [S33]
a. You can find this in your cadaver. It is suspended from the lingual nerve. It is not functionally associated with
the lingual gland, just structurally located with it. So preganglionic fibers of the corda tympani that are traveling
with it will come off and synapse into this ganglion and then their postganglionics are destined for the
submandibular and sublingual glands.
b. Look for it, suspended on the inferior surface of the lingual nerve and just superficial to the hyoglossus muscles,
one of the extrinsic tongue muscles.
XXXIV. Extrinsic tongue (L. Lingua; G. glossa) Muscles [S34]
a. These muscles basically move the tongue in and out of the mouth. Sticking your tongue out and pulling it back
in (retracting it.)
b. Intrinsic muscles are small and are within the tongue, origin and insertion in the tongue. They curl the tongue,
help with syllables. If you have the ability to curl your tongue, not everyone can, then you are using your
intrinsic muscles.
c. The latin word for tongue is lingua, the greek word is glossa. So those two terms automatically mean something
to do with the tongue.
d. We have 3 bones that are associated with this tongue. The hyoid bone, the styloid process of the temporal
bone, and the mandible. They each give rise to a muscle that is going to become an extrinsic muscle of the
tongue.
i. From the styloid process we have a styloglossus, this retracts a protruded tongue also pulls the tongue
toward the roof of the mouth.
ii. From the hyoid bone we have the hyoglossus, aids in retraction and depresses the tongue
iii. From the mandible we have the large genioglossus, which is probably the most important of the extrinsic
muscles. It depresses the tongue, and it protrudes the tongue.
e. A 4th tongue muscle is the palatoglossus, but this is more associated with the soft palate, and doesn’t really
move the tongue. So we are going to exclude it as an extrinsic tongue muscle. It is also not innervated by the
hypoglossal nerve like the other 3; it is innervated by the vagus nerve. So it is named as a tongue muscle but
really has little to do with the tongue.
XXXV. [S35]
a. Here is the older image that shows some of the same muscles. Look for the hyoglossus, styloglossus,
genioglossus, and the geniohyoid.
Gross: 8:00 - 9:00
Scribe: Laura Adams
Thursday, March 19, 2009
Proof: Brittney Wise
Dr. Tubbs
The Oral Cavity
Page 5 of 6
XXXVI. [S36]
a. This is a midline sagittal cut and we see that large genioglossus muscle that comes from the superior geniotubercle runs up and fans out into the substance of the tongue. When this contracts it propels the tongue out of
the oral cavity. When you test XII on a patient during an exam you want to make sure the tip of the tongue is in
the midline. If there is injury to XII then the tongue will deviate toward the side of the lesion.
XXXVII. [S37]
a. This is a nice technique to use in lab when looking for the hyoglossus. Use the hypoglossal nerve, as it travels
anteriorly it will travel just deep to the posterior edge of the mylohyoid and at that point it is between mylohyoid
and hyoglossus.
XXXVIII.
[S38]
a. Paralysis of genioglossus: obstruction of airway therefore pull mandible anteriorly
b. When swallowing you want to elevation/retraction the tongue to propel the bolus of food posteriorly.
Additionally, the genioglossus, because it’s attached to the mandible, because the tongue is the main
component of the oral cavity, some people who are unconscious the tongue will recede and retract into the back
of the oropharynx and potentially occlude part of their airway. The physician knows this and knows that the
genioglossus is attached to the mandible. So you can pull the mandible forward and therefore pulls the
genioglossus forward and off of the oropharynx.
c. Remember: with a XII lesion the tongue deviates to ipsilateral side
XXXIX. [S39]
a. Lingual nerve crosses the submandibular duct twice. So the green is the duct and we see the nerve crossing on
its lateral and medial side.
XL. Lymphatic drainage [S40]
a. Important because the number of carcinomas and tumors in the oral cavity and the spread of those tumor cells.
b. The gingiva and all teeth less the mandibular incisors drain into the Submandibular lymph nodes. If you have a
swelling in these nodes just under the edge of the mandible it could imply an infection of one of the teeth.
XLI.
[S41]
a. The tongue is a little more complicated. Look at the schematic on the slide. Let’s divide the tongue into anterior
2/3 and posterior 1/3.
b. Posterior 1/3 (basal) are drained by the jugulodigastric (bilaterally- so there is crisscross). These nodes are
located between the common facial vein and the internal jugular vein. It is named for the muscle and the vein in
that area.
c. Medial (central- the median strip) anterior 2/3 drains bilaterally to the deep cervical nodes along the internal
jugular vein, so the spread of tumors in that area will go to this region.
d. Lateral (marginal) anterior 2/3 drain to the Submandibular lymph nodes (the pink area in the diagram)
e. Apex or the tip of the tongue drains to the submental lymph nodes, just in the middling, underneath the
mandible.
XLII.
[S42]
a. This is a very nice slide from netters which shows you the lymphatic channels which are very difficult to see
without injecting the bodies. See the deep cervical chain, the jugulodigastric, submandibular, and the
submental.
XLIII. Tongue Arteries/Veins [S43]
a. Fairly vascular structure. The majority of that blood arises from the lingual artery, which is a branch of the
external carotid and will travel to the tongue. It gives off vessels which you will probably not fond in the lab,
these are the Dorsal lingual, Deep lingual, and the Sublingual. These arteries have veins running with them
called Vena comitantes. You always will see these running with the arteries.
b. We also notice that relationship that as the lingual artery approaches the inferior aspect of the tongue it travels
deep to the hyoglossus muscles, whereas the hypoglossal nerve travels superficial to the hyoglossus muscle.
So if you find the hyoglossus muscle look deep to it through the hyoglossus to find the lingual artery.
c. You also see the veins traveling with the hypoglossal nerve.
XLIV. Tongue Veins [S44]
a. Now some of these veins (the sublingual veins) come very close to the surface of the mucosa of the oral cavity.
So you can see these if you stick the tip of your tongue to the roof of your mouth.
b. Return to IJ directly or indirectly. Because the mucosa is so thin you can put a tablet here are it absorbs into the
sublingual vessels, fairly quickly. So if you are having chest pains you can out a nitroglycerin tablet under the
tongue and that is faster than getting the IV at the ER.
XLV. Tongue Topography [S45]
a. Remember we already divided the tongue into the posterior and anterior portions. And we do so via the sulcus
terminalis which is an upside down V shape. The posterior 1/3 of the tongue is known as the pharyngeal part of
Gross: 8:00 - 9:00
Scribe: Laura Adams
Thursday, March 19, 2009
Proof: Brittney Wise
Dr. Tubbs
The Oral Cavity
Page 6 of 6
tongue (or the root of the tongue) and everything anterior to this sulcus is the oral part of the tongue. You will
see a medial sulcus possibly on your cadaver.
b. So at the apex of the sulcus terminalis there is a little pit, that you usually have trouble finding in the lab, called
the foramen cecum, it is a blind pouch. This is the site of development of the thyroid gland. So the thyroid
develops on the back of the tongue and then descends to its adult location. In some people that doesn’t happen
or it only partially occurs so that thyroid gland remands here in the foramen cecum. So if you look in a patient’s
mouth and see a mass that lies right at the junction of the posterior third and the anterior 2/3s that could be the
so called lingual thyroid gland – (he showed a picture in class that is no longer in the PowerPoint).
XLVI. Papillae [S46]
a. Most people erroneously say that the little bumps on their tongue are called taste buds. Taste buds are
microscopic. These instead are the papilla and on the papilla you find taste buds.
b. The papilla of the human are the vallate (or circumvallate) which are just anterior to the sulcus terminalis and
you can pick those out easily.
c. We also have a lateral collection which is not developed as well in humans which are called the foliate.
d. We see fungiform, which are little islands of papilla mostly on the anterior surface if the tongue.
e. And then the filliform. The interesting thing about these is that there are no taste buds on these papilla.
XLVII. Taste [S47]
a. So taste travels through different cranial nerves.
b. For the tongue the anterior 2/3s is conveyed by corda tympani (VII) and the posterior third is more or less IX.
(vallate, foliate, and fungiform)
c. Soft palate and Oropharynx are innervated by IX.
d. The epiglottis has taste buds which are conveyed by fibers from X.
XLVIII. Taste (SVA) [S48]
a. A small portion of taste for the posterior third of the tongue is actually conveyed through X.
b. Remember that the sensory ganglia for these taste fibers reside in three ganglia, the geniculate ganglion for VII,
the inferior ganglion for IX, and the inferior ganglion for X.
XLIX. [S49]
a. You can follow back these fibers. For example the corda tympani fibers, if you trace then back through the
corda tympani you’d end for taste for the anterior 2/3s of the tongue in the geniculate ganglia.
b. If we follow those fibers back for IX then you’d end in one of these inferior ganglia.
L. General Sensation of the Tongue [S50]
a. We can say that general sensation for the posterior 2/3s of the tongue is via the glossopharyngeal, the same
nerve that does taste in that area.
b. Then the anterior 2/3 of the tongue is via the lingual nerve. So if you bite the tip you your tongue you feel that
through lingual nerve or V3.
LI. [S51]
a. You have very important spaces of the neck that are continuous with different areas and the whole reason for
learning this is that if you have infections or tumors those tumors tend to go through these discreet spaces.
b. One that I am showing you here is the lateral pharyngeal space. Sol if you pull the constrictor muscles medially
we see between the constrictors and the carotid sheath on the other side a parapharyngeal or lateral pharyngeal
space that infection or tumors can reside in.
LII. [S52]
a. Look in the syllabus at table 15.1 Tissue Spaces of the Head and Neck
[end 46 min]