ORAL CAVITY & CONTENThhhhssjdhddhdhS.pdf

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1. MR. SSEMPIJJA FRED
January05, 2023 (BMS 2.1A)
January06, 2023 (BMS 2.1B)

4. The oral region includes the oral
cavity, teeth, gingivae, tongue,
palate, and the region of the palatine
tonsils.
The oral cavity is where food is
ingested and prepared for digestion in
the stomach and small intestine.
Food is chewed by the teeth, and
saliva from the salivary glands
facilitates the formation of a
manageable food bolus
Deglutition (swallowing) is voluntarily
initiated in the oral cavity.
The voluntary phase of the process
pushes the bolus from the oral cavity
into the pharynx, the expanded part
of the alimentary (digestive) system,
where the automatic phase of
swallowing occurs.

5. The mouth cavity extends from the lips (oral orifice) to the
pharynx (oropharyngeal isthmus)
Thelips:
➢Are the 2 fleshy folds that surround the oral orifice:
➢On the outsidethey are covered by the skin
➢On the inside they are lined by the mucous membrane
➢The substance of the lips is made up by orbicularis oris
muscle &themuscles that radiate from the lips into the
face
➢Alsoincludedare the labial blood vessels & nerves,
connective tissue, & many small salivary glands
➢Philtrum is the shallow vertical groove seen in the midline
on the outer surface of the upper lip, extending from the
nasal septum to the tubercle of the upper lip
➢Labial frenulae-are the median folds of mucous
membrane that connect the inner surface of the lips to the
gums
Boundaries of the oral cavity:
Laterally: the cheeks and lips.
Roof of oral cavity: formed by the palate.
Posteriorly: the oral cavity communicates with the
oropharynx
Anteriorly: lips
Floor of mouth: mostly occupied by dorsum of the
tongue

6. •Theoropharyngeal
isthmus:
Is the junction of mouth
and pharynx &
The entrance into
pharynx is bounded:
Aboveby the soft palate
andthepalatoglossal folds
Belowby the dorsum of the
tongue
On each sideby the
palatoglossal folds &
palatopharyngeal folds
Oral cavity is subdivided into
2 parts: Oral Vestibule & Oral
cavity proper

9. Slit-like space between cheeks &
lips externally and gingivae & teeth
internally
Communicates with the exterior
through the oral fissure (oral
opening or rimaoris)between the
lips
Size of oral fissure is controlled by
the circumoral muscles: orbicularis
oris(the sphincter of the oral
fissure); buccinator, risorius, &
depressors and elevators of lips
(dilators of the fissure)
When jaws are closed, it
communicates with the oral cavity
proper behind the 3
rd
molar tooth
on each side
Superiorlyand inferiorlylimited by
the reflection of mucous membrane
from lips and cheek onto the gums

10. The lateral wall of the vestibule
is formed by the cheek
•The cheek is composed of
Buccinatormuscle, covered
laterallyby the skin &
mediallyby the mucous
membrane
•The tone of the buccinator
muscle & that of muscles of
lips keeps the walls of the
vestibule in contact with each
other
A small papillaon the mucosa
opposite the upper 2
nd
molar
tooth marks the opening of the
duct of the parotid salivary
gland(Stensen’sduct)

11. Is the space between the upper &the
lower dental arches(alveolar margins of
maxillae & mandible or maxillary &
mandibular alveolar arches) and the
teeth they bear.
When the mouth is closed and at rest,
the oral cavity proper is fully occupied by
the tongue.
It is limited laterally &anteriorlyby the
maxillary & mandibular alveolar arches
housing the teeth.
Posteriorly, the oral cavity communicates
with the oropharynx(oral part of the
pharynx)
Oral cavity proper has a Roof& a Floor
Roof of oral cavity proper is formed by
the hard palate anteriorly and the soft
palate posteriorly
hard
soft palate
mylohyoid

12. Floor of oral cavity properis formed largely
by the anterior two thirds of the tongue &
by the reflection of the mucous membrane
from the sides of tongue to the gum of
mandible
Mylohyoid muscle-paired muscle running
from mandible to hyoid bone, forming the
floor of the oral cavity: 1) the mylohyoid
elevates the hyoid and the tongue e.g.
during swallowing & speaking; 2) It also
functions in reinforcing the floor of mouth;
3) mylohyoid separates the submandibular
space below from the sublingual space
above & around the posterior border of
mylohyoid, these spaces communicate.
Floor of oral cavity is covered with mucous
membrane (oral mucosa)
In the midline, a fold of mucous membrane,
the frenulum of the tongue (lingual
frenulum), connects undersurface of tongue
in midline to the floor of the mouth
hard
soft palate
mylohyoid

13. Submandibular duct of submandibular
gland (Wharton’s duct)opens into the
floor of mouth on the summit of a small
papilla (sublingual papilla or sublingual
caruncle)on either side of the frenulum
of the tongue
Lateral to frenulum, mucous membrane
forms a fringed fold (plica fimbriata)
extending backward & laterally from the
papilla
Sublingual gland lies beneath the oral
mucosa, close to the frenulum of the
tongue
The sublingual gland projects up into the
mouth, producing a low fold of mucous
membrane, the sublingual fold (plicae
sublingualis)
Numerous ducts of sublingual gland (8-
20 sublingual ducts or Ducts of Rivinus)
open directly & separately on the crest or
summit of the sublingual fold, on either
side of the lingual frenulum

14. CAVITY OF MOUTH

15. oMucous membrane of the vestibule
▪In the vestibule, mucous membrane is tethered to buccinator muscle
by elastic fibers in the submucosa that prevent redundant folds of
mucous membrane from being bitten between the teeth when jaws
are closed
oMucous membrane of the gingiva (gum)
▪Mucous membrane of the gingiva is strongly attached to the alveolar
periosteum
oFolds of mucous membrane in the mouth
▪Frenulum of the tongue (lingual frenulum)-a fold of mucous
membrane that connects the undersurface of tongue in midline to the
floor of the mouth
▪Labial frenulae-are the median folds of mucous membrane that
connect the inner surface of the lips to the gums
▪Plica fimbriata-a fringed fold of mucous membrane lateral to the
lingual frenulum extending backward & laterally from the sublingual
papilla
▪Sublingual fold (plicae sublingualis)-a low fold of mucous membrane
formed close to & on either side of the lingual frenulum whenthe
sublingual gland projects up into the mouth

16. Mostly by the
maxillarynerve
through its
branches:
•Greater palatine
nerve
•Lesser palatine nerves
•Nasopalatine nerve
Glossopharyngeal
nervesupplies the
region of the soft
palate

17. oSensory innervation of the mouth
▪Roof: by greater palatine, nasopalatineand lesser
palatinenerves-all sensations (branches of maxillary
division of trigeminal nerve, CN V2)
▪Floor: by the lingualnerve-common sensation (branch
of mandibular division of trigeminal nerve, CN V3);the
taste fibers travel in the chorda tympani(branch of
facial nerve, CN VII)
▪Cheek: by buccalnerve (branch of mandibular division
of trigeminal nerve, CN V3)
oMotor
▪Muscle in the cheek (buccinator) and the lip
(orbicularis oris) are supplied by branches of facial
nerve, CN VII
-Buccinator-buccal branch of facial nerve
-Orbicularis oris-buccal & mandibular branches of facial
nerve

19. oClinical significance of oral examination
▪Mouth is among the important body areas of examination by
medical practitioners
▪Structures visible in the mouth,color of mucous membrane,
sensory nerve supply &lymphatic drainage of the mouth should
be known
▪The close relationship of the lingual nerve to lower 3
rd
molar tooth
should be remembered, e.g. during tooth extraction of molar teeth
▪The close relation of duct of submandibular gland (Wharton’s duct)
to the floor of the mouthmay enable one to palpate a calculus in
cases of periodic swelling of submandibular salivary gland
▪Parotid Sialogram. Locationofduct of parotid salivary gland
(Stensen’sduct)in vestibule of mouth opposite upper 2
nd
molar
tooth mayenable the duct of parotid gland to be demonstrated by
injecting a radio-opaque contrast through a cannula placed in
mouth of the duct (Parotid Sialogram). Sialography-radiographic
examination of salivary glands usually by injection of a small
amount of contrast medium into the salivary duct of a single
gland, followed by routine X-ray projections

22. is a mobile muscular organ-a mass of striated muscles
covered with the mucous membrane
partly in the oral cavity & partly in the oropharynx.
involved with mastication, taste, deglutition(swallowing),
articulation, and oral cleansing; however, its main functions
are forming words during speaking and squeezing food into
the oropharynx when swallowing.
Striated muscles of the tongue attach it to styloid process &
soft palate above and to mandible & hyoid bone below.
The 4 intrinsic & 4 extrinsic muscles in each half of the
tongue are separated by a median fibrous lingual septum,
which merges posteriorly with the lingual aponeurosis
Tongue is divided into right and left halves by a vertical
section of fibrous tissue, the median orlingual septum
Results in a shallow midline/median groove (sulcus) of the
tongue on tongue’s upper surface that divides the tongue
into right and left halves
Two surfaces:
•Dorsal (superior) surface
•Ventral (inferior) surface
Two parts:
•Thebody or oral partor anterior part (anterior two
thirds of the tongue). Body has an apex/tip of the
tongue(rests on incisor teeth)
•Theroot orpharyngeal partor posterior part (posterior
third of the tongue). Root has a base of the tongue
(attached portion)

23. The parts of the tongue are the bodyand root
The tongue has a root, a body, an apex
The root of the tongue is the part of the tongue
that rests on the floor of the mouth. It is usually
defined as the posterior third of the tongue.
The body of the tongue is the anterior two
thirds of the tongue
The body and root are separated by the
terminal sulcus (groove) and foramen cecum.
The arms of the V-shaped terminal sulcus
diverge from the foramen, demarcating the
posterior third of the tongue from the anterior
two thirds.
The apex (tip)of the tongue is the anterior end
of the body, which rests against the incisor
teeth.
The body and apex of the tongue are extremely
mobile.
The tongue has two surfaces: curved dorsum
(superior surface), and aninferior surface

25. Dorsum of tongue is the posterosuperior surface, located partly in the oral cavity & partly in the
oropharynx
Mucous membrane of upper (dorsal) surface of tongue is divided into anterior two third (anterior
part ororal part) and posterior one third (posterior part or pharyngeal part)by a V-shaped
groove/sulcus, the sulcus terminalis (terminal sulcus).
The apex/angle of the sulcus projects/points posteriorly to (is marked by) a small blind
pit/foramen, the foramen cecum
Foramen cecum, a non-functional embryological remnant, marks the site of the upper/proximal
end of the thyroglossal duct from which the thyroid gland developed
The anterior part (oralpart)is the visible part situated at the front in the oral cavity proper &
makes up roughly two-thirds the length of the tongue.
The posterior part (pharyngealpart)is the part closest to the throat, located in the oropharynx,
roughly one-third of the length of tongue
These parts differ in terms of their embryological development and nerve supply
Mucous membrane of anterior 2/3 of tongue: derived from 1
st
pharyngeal arches on each side;
here the mucous membrane on each side is innervated by the lingual nerve (branch of the
mandibular division of trigeminal nerve, CN V3 (common or general sensations-touch &
temperature)-CN V is the nerve of the 1
st
pharyngeal arch; & chorda tympani branch of CN VII
(special sensation-taste) also supplies this area (CN VII is the nerve of the 2
nd
pharyngeal arch)
Mucous membrane of posterior 1/3 of tongue is formed from the 3rd pharyngeal arches & is
innervated by glossopharyngeal nerve, CN IX (common sensations and taste)…CN IX
(glossopharyngeal nerve) is the nerve of the 3
rd
pharyngeal arch
NOTE: Muscles of tongue are derived from occipital myotomes, which are closely related to
developing hind-brain & later migrate inferiorly & anteriorly around pharynx & enter tongue.
The migrating myotomes carry with them their innervation, the 12
th
cranial nerve, and this
explains why all the tongue muscles (EXCEPT the palatoglossus) receive their motor nerve
supply from CN XII (hypoglossal nerve). Thepalatoglossusis derived from the 4
th
pharyngeal
arch & is innervated by the pharyngeal plexus with branches from vagusnerve (vagusnerve is
the nerve of the 4
th
pharyngeal arch) & glossopharyngeal nerve (nerve of 3
rd
pharyngeal arch)

26. Thyroglossal duct
Thyroglossal duct isan embryological anatomical
structure forming an open connection between
the initial area of development of the thyroid
gland and its final position. It is located exactly
mid-line, between the anterior 2/3 & posterior
1/3 of the tongue.
The thyroid gland starts developing in the
oropharynx in the fetus and descends to its final
position taking a path through the tongue, hyoid
bone and neck muscles.
The connection between its original position and
its final position is the thyroglossal duct.
This duct normally atrophies and closes off as
the foramen cecum before birth but can remain
open in some people.
Foramen cecum is an embryologic remnant &
marks the site of the upper end of the
thyroglossal duct
Clinical significance: A thyroglossal duct that
fails to atrophy is called a persistent thyroglossal
duct, a condition that may lead to the formation
of a thyroglossal duct cyst.

27. The margin of the tongue is related on each side to the lingual gingivae & lateral teeth.
The mucosa over the anterior part of dorsum of the tongue is thin & closely attached to underlying
muscle.
A shallow midline groove of the tongue divides tongue into right and left halves. The groove also
indicates the site of fusion of the embryonic distal tongue buds
Upper surface ofanterior two thirds of the tongue: mucosa is rough due to small lingual papillae:
▪Filiform papillae
-Numerous elongated conical keratinized projections on dorsum of tongue
-Contain afferent nerve endings that are sensitive to touch.
-These scaly, conical projections are pinkish gray & are arranged in V-shaped rows that are parallel
to the terminal sulcus, except at the apex, where they tend to be arranged transversely.
▪Fungiform (clavate) papillae
-Numerous minute elevations on dorsum of tongue
-Pink or red spots
-Mushroom-shaped, the tip being broader than the base (i.e. clavate…increasingly wider from base
to distal end)
-are scattered among the filiform papillae but are most numerous at the apex and margins of the
tongue
-The epithelium of many of these papillae has taste buds
➢Vallate (circumvallate) papillae
-Large & flat topped
-1 of 8 or 10 projections from the dorsum of tongue forming a row anterior to & parallel with the
sulcus terminalis (lie directly anterior to terminal sulcus & are arranged in a V-shaped row)
-Each papilla is surrounded by a circular trench (fossa) having a slightly raised wall (vallum)
-On the sides of the vallate papilla & the opposed margin of the vallum are numerous taste buds
-I.e. They are surrounded by deep moat-like trenches, the walls of which are studded with taste
buds. The ducts of the serous glands of the tongue open into the trenches.
➢Foliate papillae: Small lateral folds of the lingual mucosa. They are poorly developed in humans.
NOTE: The vallate, foliate, and most of the fungiform papillae contain taste receptors in the taste
buds.

28. •Filiform papillae: rough surface
•Fungiform papillae: house taste buds
•Circumvallate papillae: house taste buds,
•Foliate papillae: posterolateral; taste buds

29. Mucosa of posterior part of the
tongue is thick & freely movable
Upper surface ofPosterior one
third of the tongue: mucosa is
devoid of lingual papillae& taste
buds but shows an irregular
(nodular) appearance caused by
presence underlying lymphoid
nodules, the lingual tonsil
The pharyngeal part of the
tongue constitutes the anterior
wall of the oropharynx and can
be inspected only with a mirror
or downward pressure on the
tongue with a tongue depressor.

30. The inferior surface of the tongue is covered with a
thin, transparent mucous membrane through which
one can see the underlying veins.
Mucous membrane on inferior surface of tongue is
smooth (no papillae)
Mucosa is reflected from tongue to floor of mouth
In the midline anteriorly, a mucosal fold, the
frenulum of the tongue (lingual frenulum)connects
the inferior surface of tongue to the floor of the
mouth
The frenulum allows the anterior part of the tongue
to move freely
On each (lateral) side of the frenulum, a deep
lingual veinis visible through the thin mucosa
A sublingual caruncle (papilla) is present on each
side of the base of the lingual frenulum that includes
the opening of the submandibular duct from the
submandibular salivary gland.
Lateral to the lingual vein, the mucous membrane
forms a fringed (fimbriated) fold, the plica fimbriata
(fimbriated fold of the tongue)
The plica fimbriata is a slight fold of the mucous
membrane on the underside of the tongue which
runs laterally & backwards from the sublingual
papillaon either side of the lingual frenulum

32. DORSUM OF TONGUE VENTRAL SURFACE OF TONGUE

34. Tongue is a mass of muscles covered by mucous membrane
Muscles of the tongue are derived from the occipital
myotomes, which at 1
st
are closely related to the developing
hind-brain & later migrate inferiorly & anteriorly around
pharynx & enter tongue.
Migrating myotomes carry with them their innervation, the
12
th
cranial nerve, and this explains the long curving course
taken by the 12
th
cranial nerve as it passes downward &
forward in the carotid triangle of neck & eventually passes up
again over the tongue muscles it supplies into the tongue
Therefore all the tongue muscles (EXCEPT the palatoglossus)
receive their motor nerve supply from CN XII (hypoglossal
nerve).
The palatoglossusis derived from the 4
th
pharyngeal arch &
is innervated by the pharyngeal plexus with branches from
vagusnerve (vagusnerve is the nerve of the 4
th
pharyngeal
arch) & glossopharyngeal nerve (glossopharyngeal nerve is
the nerve of the 3
rd
pharyngeal arch)

35. The tongue is
composed of two types
of muscles:
•Intrinsic
•Extrinsic
There are 4 intrinsic &
4 extrinsic muscles in
each half of the
tongue, these are
separated by a median
fibrous lingual septum,
thereby dividing the
tongue into right & left
halves

36. Confined to tongue
They have their attachments
entirely within the tongue & are
not attached to bone (no bony
attachment)
Consist of:
•Longitudinal fibers: the superior
& inferior longitudinal muscles
•Transverse fibers/muscles
•Vertical fibers/muscles
Main Function: Alter the shape of
the tongue
But they can alter the position of
tongue as well

37. Originate outside the tongue & attach to
it. Attached to bones & soft palate
These muscles attach tongue to styloid
process & soft palate above & to
mandible & hyoid bone below.
Connect the tongue to the surrounding
structures: the soft palate and the
bones(mandible, hyoid bone, styloid
process)
Include:
•Palatoglossus
•Genioglossus
•Hyoglossus
•Styloglossus
Main Function: Help in movements of
the tongue (alter the position of tongue)
But they can alter shape of tongue as
well

41. It is not true that a single action or movement of
the tongue is provided by a single muscle
It is true that muscles of the tongue do not act in
isolation & some muscles perform multiple actions
It is true that parts of a single muscle are capable
of acting independently, producing different, even
antagonistic actions
In general, however, extrinsicmuscles alter the
positionof the tongue while intrinsicmuscles alter
its shape.

42. Protrusion & Depression of tongue:
▪Genioglossus on both sides acting together
Retraction & Depression of tongue:
▪Hyoglossus on both sides acting together
Retraction & Elevation (especially of posterior
1/3):
▪Styloglossus and palatoglossus on both sides
acting together
NOTE: All the extrinsic muscles of the tongue
retract and elevate (hyoglossus depresses) the
tongue EXCEPT the genioglossus which
protrudes & depresses the tongue

43. A. Right & left muscles
contract equally together &
as a result
(B) tip of tongue is
protruded in midline.
C. Right hypoglossal nerve
(innervates
genioglossus muscle & intrinsic
tongue muscles on the same
side), is cut & as a result
rightside of the tongue is
atrophied and wrinkled.
D. When the patient is asked
to protrude tongue, the tip
points to the side of nerve
lesion.
E. The origin & insertion &
direction of pull of the
genioglossus muscle.

44. The superior & inferior longitudinal
muscles act together to make the tongue
short and thick and to retract the
protruded tongue.
The transverse& vertical muscles act
simultaneously to make the tongue long
and narrow, which may push the tongue
against the incisor teeth or protrude the
tongue from the open mouth(especially
when acting with the posterior inferior
part of the genioglossus).

46. The tongue is highly
sensitive, with 4 cranial
nerves contributing sensory
fibers to it
There are 4 basic taste
sensations: sweet, salty,
sour, bitter
Sweetness is detected at
the apex, saltiness at the
lateral margins, & sourness
& bitterness at the
posterior part of the
tongue.
All other tastes expressed
by gourmets are olfactory
(smell and aroma)

47. 1. Sensory nerve to mucosa of anterior two thirds
of tongue:
➢General sensations (touch & temperature):
Lingual nerve (branch of mandibular division of
trigeminal nerve, CN V3)
➢Special sensation (taste): chorda tympani
(branch of facial nerve, CN VII), EXCEPTfor
the circumvallate papillae which are
suppliedby the glossopharyngeal nerve, CN IX
➢NOTE:
A. Taste fibers of chorda tympani are carried to the
anterior 2/3 of the tongue by the lingual nerve
(chorda tympani joins the lingual nerve in the
infratemporal fossa &runs anteriorly in its sheath):
Facial nerve emerges on anterior surface of
hindbrain between pons & medulla oblongata→
internal acoustic meatus →facial canal →
geniculate ganglion (within facial canal)→chorda
tympani (branch of CN VII) →submandibular
ganglion →lingual nerve (branch of CN V3)

48. B. Therefore, injury to the facial nerve at the
stylomastoid foramen neither leads to loss of taste on
the anterior 2/3 of the tongue nor altered secretion of
salivary glands because chorda tympani (carries taste
fiberson anterior 2/3 of tongue & PS secretomotor
fibersfor submandibular & sublingual salivary glands)
has already branched off from facial nerve (chorda
tympani arises from facial nerve within the facial
canal) BUT affects muscles of facial expression
C. Also injury to the facial nerve at the stylomastoid
foramen does not cause altered secretion of lacrimal
glands (tearing) because the greater petrosal nerve
carrying PS secretomotor fibersfrom the facial nerve
to lacrimal gland has already branched off from the
facial nerve (greater petrosal nerve arises from facial
nerve at the geniculate ganglion in facial canal), BUT
affects muscles of facial expression
Hence, injury to the facial nerve at the
stylomastoid foramen causes paralysis of facial
muscles without loss of taste on the anterior
2/3 of the tongue or altered secretion of the
lacrimal & salivary glands.

50. Relationship of lingual nerve withsubmandibular & sublingual
salivary glands & submandibular ganglion
The body and parts of the ramus of the mandible have been removed.

51. Dissection of temporal & infratemporal region
In this deep dissection of the infratemporal region, more of the ramus of the mandible, the lateral
pterygoid muscle, and most branches of the maxillary artery have been removed. Branches of the
mandibular nerve (CN V
3), including the auriculotemporal nerve, and the second part of the
maxillary artery pass between the sphenomandibularligament and the neck of the mandible.

53. •RECALL: Branches of Facial Nerve (CN
VII): Motor and sensory branches
➢1. Motor: muscles of facial expression (5
terminal branches)
➢2. Motor: nerve to stapedius-supplies the
stapedius muscle in the middle ear
➢3. A. Taste buds of the anterior 2/3 of the tongue
(fromchorda tympani via lingual nerve)
➢3. B. PS secretomotor fibersfor submandibular &
sublingual salivary glands (chorda tympani via
lingual nerve). PS fibers from chorda tympani
nerve travel with lingual nerve to submandibular
and sublingual salivary glands. These nerve
fibers synapse in the submandibular ganglion,
which hangs from the lingual nerve
➢4 A. PS secretomotor fibersfrom the facial nerve
to lacrimal gland & glands of nose & palate (via
the greater petrosal nerve)
➢4. B. The greater petrosal nerve also contains
taste fibersfrom the palate

54. 2. Sensory nerve supply to mucosa of the
posteriorthirdof tongue & vallate papillae
•General sensation & special sensation
(taste): lingual branch of glossopharyngeal
nerve (CN IX)
•Circumvallate papillae are also supplied by
the glossopharyngeal nerve
3. Sensory nerve supply to mucosa of base of
tongue (small area of the tongue just anterior
or adjacent to the epiglottis)
➢Mostly general but also some special
sensations: internal laryngeal nerve
(branch of superior laryngeal nerve,
branch of the vagusnerve-CN X)
➢These mostly sensory nerves also carry
parasympathetic secretomotor fibers to
serous glands in the tongue.

55. All muscles of the tongue, except the
palatoglossus (actually a palatine muscle
supplied by the pharyngeal plexus),
receive motor innervation from CN XII,
the hypoglossal nerve
Intrinsic muscles:
▪Hypoglossal nerve
Extrinsic muscles:
▪All supplied by thehypoglossal nerve,
except the palatoglossus
The palatoglossus is supplied by the
pharyngeal plexus of vagusnerve
NOTE: Pharyngeal plexus-network of
nerve fibers innervating most of the palate
& pharynx. It is located on the surface of
the middle pharyngeal constrictor muscle;
Larynx, which is innervated by superior
and recurrent laryngeal nerve from vagus
nerve (CN X), is not included

57. Arteries:
▪Arteries of tongue are derived from lingual
artery(branch of external carotid)-
▪On entering tongue, lingual artery passes deep
to hyoglossus muscle.
-Dorsal lingual arteries supply the posterior part
(root) of tongue
-Deep lingual arteries supply the anterior part
(body) of tongue
-Deep lingual arteries communicate with each
other near apex of tongue while dorsal lingual
arteries are prevented from communicating by
the lingual septum
-Sublingual arteries–provide blood supply to
floor of mouth including sublingual salivary
glands
▪Tonsillar branch of facial artery
▪Ascending pharyngeal artery (branch of
external carotid)
Veins:
▪Deep lingual veins, begin at the apex of the
tongue, run posteriorly beside the lingual
frenulum to join the sublingual vein.
▪and then receives the dorsal lingual veins.
▪They all drain into the lingual vein
▪All these lingual veins terminate, directly or
indirectly, in the IJV via the lingual vein
▪The sublingual veins in elderly people are often
varicose (enlarged and tortuous).
Hypoglossal
nerve
Lingual
artery & vein
Facial vein
Deep lingual
artery & vein
Dorsal lingual
artery & vein
Sublingual
vein
Common trunk of facial
vein & lingual vein

60. Lymphatic drainage of tongue is
exceptional.
Most of the lymphatic drainage
converges toward & follows the venous
drainage; however, lymph from tip of
tongue, frenulum, & central lower lip
runs an independent course. Lymph
from the tongue takes four routes:
•Lymph from posterior third drains into
the superior deep cervical lymph
nodes.
•Lymph from the medial part of the
anterior two thirdsdrains directly to the
inferior deep cervical lymph nodes.
•Lymph from the lateral parts of the
anterior two thirdsdrains to the
submandibular lymph nodes.
•The apex and frenulum drain to the
submental lymph nodes.
The posterior third and the medial part
of the anterior two thirds drain
bilaterally.

61. Tip:
•Submental lymph
nodes bilaterally &
then to deep cervical
lymphatic nodes
Anterior two third:
•Submandibular
unilaterally & then
deep cervical nodes
Posterior third:
•Deep cervical nodes
(jugulodigastric
mainly, but also
jugulo-omohyoid
nodes)

64. Mastication, taste, deglutition(swallowing),
articulation, & oral cleansing
Main functions are: forming words during
speaking &squeezing food into the oropharynx
when swallowing
➢The tongue is the most important articulator for
speech production. During speech, the tongue
can make amazing range of movements
Primary function of tongue is to provide a
mechanism for taste.
➢Taste buds are located on different areas of
tongue, but are generally found around the
edges.
Sweetness is detected at apex, saltiness at
lateral margins, & sourness & bitterness at
posterior part of tongue.
➢Taste buds are sensitive to four basic tastes:
Bitter, Sour, Salty & Sweet

65. The tongue is needed for
sucking, chewing,
swallowing, eating,
drinking, kissing, sweeping
the mouthfor food debris
and other particles and for
making funny faces
(poking the tongue out,
waggling it)
Trumpeters and horn &
flute players have very well
developed tongue muscles,
and are able to perform
rapid, controlled
movements or articulations

66. Sublingual Absorption of Drugs. For quick absorption of a drug,
e.g., when nitroglycerin is used as a vasodilator in angina
pectoris, pill or spray is put under tongue where it dissolves &
enters the deep lingual veins in <1 min
Lacerations of tongue-woundof tongue caused by teeth after a
blow to chin; accidental bite of tongue during chewing, recovery
from anesthesia, or epileptic attack. Stop bleeding by grasping
tongue between fingers & thumb posterior to the laceration-
occludes the branch of lingual artery
Cleft (bifid tongue)
Tongue-tie (ankyloglossia)-partial/complete fusion of tongue to
floor of mouth due to a large lingual frenulum or abnormal
shortness of the frenulum linguae.
Frenectomy(cutting frenulum). An overly large lingual frenulum
(tongue-tie) interferes with tongue movements and may affect
speech & suckling in infants. In such cases it may be necessary
to free the tongue for normal movement and speech.
Tongue-swallowing-a slipping back of the tongue against the
pharynx causing choking
Paralysis of the Genioglossus. When genioglossus is paralyzed,
the tongue has a tendency to fall posteriorly, obstructing the
airway & presenting the risk of suffocation. Total relaxation of
genioglossus occurs during general anesthesia; therefore, an
airway is inserted in an anesthetized person to prevent the
tongue from relapsing.

67. Lesion of the hypoglossal nerve
•Injury to hypoglossal nerve, tongue deviates to the
affected side
•The protruded tongue deviates toward the side of the
lesion
•Tongue is atrophied & wrinkled
Gag Reflex.when posterior part of tongue is touched, the
individual gags. CN IX & CN X are responsible for muscular
contraction of each side of pharynx. Glossopharyngeal
branches provide the afferent limb of the gag reflex.
Lingual Carcinoma A lingual carcinoma in posterior part of
tongue metastasizes to superior deep cervical lymph nodes on
both sides, whereas a tumor in anterior part usually does not
metastasize to inferior deep cervical lymph nodes until late in
the disease. Because these nodes are closely related to IJV,
metastases from tongue may be widely distributed through
the submental & submandibular regions & along the IJVs in
the neck.
Thyroglossal Duct Cyst. A cystic remnant of the thyroglossal
duct, associated with development of the thyroid gland, may
be found in the root of the tongue & be connected to a sinus
that opens at the foramen cecum. Surgical excision of the
cyst may be necessary. Most thyroglossal duct cysts are in
the neck, close or just inferior to the body of the hyoid bone

69. Forms the roofof
the oral cavity &
floor of the nasal
cavity
Has two parts:
•Hard(bony)
palate
anteriorly
•Soft(muscular)
palate
posteriorly
hard
soft palate

70. Composed of submucosa, mucosa & ciliated columnar
epitheliumon its surface
The mucosa of the hard palate includes abundant palatine
glands
Mucosa of hard palate is tightly bound to underlying bone;
consequently, submucous injections here are extremely
painful.
The lingual gingiva, the part of the gingiva covering the
lingual surface of the teeth and the alveolar process, is
continuous with the mucosa of the palate; therefore,
injection of an anesthetic agent into the gingiva of a tooth
anesthetizes the adjacent palatal mucosa.
Deep to the mucosa are mucus-secreting palatine glands.
The orifices of the ducts of these glands give the palatine
mucosa a pitted (orange-peel) appearance.
In the midline, posterior to the maxillary incisor teeth, is the
incisive papilla. This elevation of the mucosa lies directly
anterior to the underlying incisive fossa or incisive foramen
Radiating laterally from the incisive papilla are several
parallel transverse palatine folds or rugae. These folds assist
with manipulation of food during mastication.
Passing posteriorly in the midline of the palate from the
incisive papilla is a narrow whitish streak, the palatine raphe.
It may present as a ridge anteriorly and a groove posteriorly.
The palatine raphe marks the site of fusion of the embryonic
palatine processes (palatal shelves)
You can feel the transverse palatine folds and the palatine
raphe with your tongue.

72. Forms the anterior 2/3 of the
palate
Lies in the roof of the oral cavity
Forms the floor of the nasal cavity
Formed by:
•Palatine processes of maxillae
in front
•Horizontal plates of palatine
bonesbehind
Bounded by alveolar arches
The medial end of the posterior
border of the horizontal plate of
palatine bone is sharp & pointed,
&, when united with that of the
opposite bone, forms a projecting
process, the posterior nasal
spinefor the attachment of the
musculus uvulæ. It serves as a
cephalometric landmark.

73. Posteriorly, continuous with soft palate
Its undersurface covered by
mucoperiosteum
Shows transverse ridges in the anterior
parts-radiating laterally from incisive
papilla are several parallel transverse
palatine folds or rugae
Incisive fossa/foramen, depression in
midline of hard palate posterior to central
incisor teeth into which the two lateral
incisive canals open (orifices of two lateral
canals are visible)
Nasopalatine nerves pass from nose
through a variable number of incisive canals
that open into the incisive fossa
Medial to 3rd molar tooth, the greater
palatine foramenpierces the lateral border
of hard palate
Greater palatine vessel and nerve emerge
from this foramen & run anteriorly on the
palate.
Lesser palatine foramina posterior to the
greater palatine foramen pierce the
pyramidal process of the palatine bone.
These foramina transmit the lesser palatine
nerves & vessels to the soft palate and
adjacent structures

74. Is a mobile posterior 1/3 of palate
Attached to the posterior border of the hard palate
Suspended from horizontal plates of palatine bone
Extends posteroinferiorly as a curved free margin from which
hangs a conical process in the midline of the free posterior
border, the uvula
Is continuous at the sides with the lateral wall of the pharynx
Covered on its upper and lower surfaces by mucous membrane
The two parts of the soft palate:
-1. Anterior aponeurotic part (palatine aponeurosis) which
attaches to the posterior edge of the hard palate
-2. Posterior muscular part
The soft palate is composed of:
•Muscle fibers
•Anaponeurosis (palatine aponeurosis)
•Lymphoid tissue
•Glands-Deep to mucosa are mucus-secreting palatine
glands
•Taste buds
•Blood vessels
•Nerves
When a person swallows, soft palate initially is tensed to allow
tongue to press against it, squeezing bolus of food to back of
mouth. The soft palate is then elevated posteriorly & superiorly
against wall of pharynx, thereby preventing passage of food
into nasal cavity

75. A few taste buds are located in epithelium covering
the oral surface of the soft palate, the posterior
wall of the oropharynx, and the epiglottis.
Laterally, the soft palate is continuous with the
wall of the pharynx & is joined to the tongue &
pharynx by the palatoglossal& palatopharyngeal
arches, respectively
Fauces(L. the throat) is the space between cavity
of the mouth & the pharynx.
The faucesis bounded superiorly by soft palate,
inferiorly by root of tongue, & laterallyby the
pillars of the fauces, the palatoglossal &
palatopharyngeal arches
Isthmus of the fauces(oropharyngeal isthmus)is
the short constricted space that establishes the
connection between oral cavity proper & the
oropharynx.
The isthmus is bounded anteriorly by the
palatoglossal folds and posteriorly by the
palatopharyngeal folds.
Palatine tonsils, are masses of lymphoid tissue,
one on each side of the oropharynx. Each tonsil is
in a tonsillar sinus (fossa), bounded by (located
between) the palatoglossal and palatopharyngeal
arches and the tongue.

76. Palatoglossal arch-fold of
mucous membrane containing
the palatoglossus muscle, which
extends from soft palate to side
of tongue. Palatoglossal arch
marks where the mouth
becomes the pharynx
Palatopharyngeal arch-fold of
mucous membrane behind the
palatoglossal arch that runs
downward & laterally to join the
pharyngeal wall; the muscle
contained within this fold is the
palatopharyngeusmuscle

79. Fibrous sheath/sheet
Attached to posterior
border of hard palate
Is thick anteriorly & thin
posteriorly.
Formed by the expanded
tendon of tensor veli
palatini muscle
Splits to enclose
musculusuvulae
Gives origin & insertion
to other palatine muscles
The soft palate is
strengthened by the
palatine aponeurosis

80. The five muscles of the soft palate arise from
the base of the cranium & descend to the
palate
The soft palate may be elevated so that it is in
contact with the posterior wall of the pharynx.
This closes the pharyngeal isthmus, requiring
that one breathes through the mouth.
The soft palate may also be drawn inferiorly
so that it is in contact with the posterior part
of the tongue. This closes the isthmus of the
fauces, so that expired air passes through the
nose (even when the mouth is open) and
prevents substances in the oral cavity from
passing to the pharynx.
Tensing the soft palate pulls it tight at an
intermediate level so that the tongue may
push against it, compressing masticated food
and propelling it into the pharynx for
swallowing
Actions: Allthe muscles of the soft palate
elevate (raise) the soft palate EXCEPT tensor
velipalatine

81. Tensor velipalatini
•Origin: spine of sphenoid, auditory tube
•Insertion: with muscle of opposite side,forms
palatine aponeurosis
•Muscle fibers of tensor velipalatini converge as they
descend from their origin to form a narrow tendon,
which turns medially around the pterygoid hamulus.
The tendon together with that of the opposite side
expands to form the palatine aponeurosis. When
muscles of the 2 sides contract, the soft palate is
tightened so that the soft palate is moved upward or
downward as a tense sheet
•Nerve: Nerve to medial pterygoid (a branch of
mandibular nerve, CN V3)
•Action:Tenses soft palate & opens mouth of auditory
tube during swallowing & yawning
Levatorvelipalatini
•Origin: petrous part of temporal bone, auditory tube
•Insertion:palatine aponeurosis
•Nerve: Pharyngeal plexus (pharyngeal branch of
vagusnerve, CN X, via pharyngeal plexus)
•Action:Raises soft palate during swallowing &
yawning

82. Musculus uvulae
•Origin: posterior border of hard palate (posterior
nasal spine) & palatine aponeurosis
•Insertion: mucosa of uvula
•Nerve: Pharyngeal plexus
•Action: Elevates (raises) uvula (palatine uvula)
Palatoglossus
•Origin:palatine aponeurosis
•Insertion:side of tongue
•Nerve: Pharyngeal plexus
•Action:pulls root/posterior part of tongue
upward, draws soft palate onto tongue,
narrowing/closing oropharyngeal isthmus
Palatopharyngeus
•Origin: Hard palate & palatine aponeurosis
•Insertion: posterior border of thyroid cartilage,
lateral wall of pharynx
•Nerve: Pharyngeal plexus
•Action:Tenses soft palate, Elevates wall of
pharynx (pulls walls of pharynx superiorly,
anteriorly, & medially) &
pulls palatopharyngeal folds medially during
swallowing

83. Muscles

85. Pharyngeal isthmus (communicating channel between
nasal & oral parts of the pharynx) is closed by raising of
soft palate. Closure occurs during production of explosive
consonants in speech or during swallowing.
Soft palate is raised by contraction of levatorvelipalatini
on each side, at the same time, the upper fibers of the
superior pharyngeal constrictor muscle contract & pull the
posterior pharyngeal wall forward; the palatopharyngeus
muscles on both sides also contract so that the
palatopharyngeal arches are pulled medially like side
curtains. By these means, the nasal part of the pharynx
is closed off from the oral part.
What is the role of a) palatoglossus muscleb)
stylopharyngeusmuscleduring movement of the soft
palate in the process of swallowing?

86. The sensory nerves of the palate are
branches of the maxillarynerve (CN V
2)
that branch from the pterygopalatine
ganglion
Palatine nerves which are branches of the
maxillary division of the trigeminal nerve:
•Greater palatine nerve-enters palate
through greater palatine foramen; &
supplies hard palate (gingivae, mucosa
& glands of most of hard palate).
•Lesser palatine nerves-enter palate
through lesser palatine foramina; supply
soft palate.
•Nasopalatine nerve-enters the front of
hard palate through incisive canal in
incisive fossa/foramen; supplies mucosa
of anterior part of hard palate.
•The palatine nerves accompany the
arteries through the greater & lesser
palatine foramina, & incisive canals in
incisive fossa, respectively.
Glossopharyngealnervealso supplies the
region of the soft palate

87. All the muscles of soft palate, except tensor
velipalatini, are supplied by the:
•Pharyngeal plexus of nerves (pharyngeal
branch of vagusnerve, CN X)
Tensor velipalatini supplied by the:
•Nerve to medial pterygoid, a branch of the
mandibular division of the trigeminal
nerve (CN V3)

88. The palate has a rich blood supply, chiefly from 1) greater palatine
artery on each side, but also 2) the lesser palatine arteries, 3) the
terminalbranch of sphenopalatine artery, & 4) theascending palatine
artery
Branches of maxillaryartery
•Greater palatine artery-branch ofdescending palatine artery
(branch of maxillary artery). The greater palatine artery passes
through greater palatine foramen & runs anteromedially; supplies
hard palate.
•Lesser palatine arteries-Lesser palatine artery is a smaller branch
of the descending palatine artery, enters the palate through the
lesser palatine foramen and anastomoses with the ascending
palatine artery (branch of the facial artery), & supply the soft
palate. It gives off tonsillar branches to the palatine tonsils.
•Sphenopalatine(nasopalatine)artery-branch of maxillary artery
which passes through sphenopalatine foramen into the cavity of
nose, at the back part of the superior meatus. Here it gives off its
posterior lateral nasal branches. Crossing the under surface of the
sphenoid, the sphenopalatine artery ends on the nasal septum as
the posterior septal branches. Here it will anastomose with the
branches of the greater palatine artery in incisive canal. Posterior
septal branch of sphenopalatine artery terminates as the
nasopalatine artery, enters the palate through the incisive canal in
incisive fossa anastomosing with terminal branch of greater
palatine artery; supplies hard palate
Ascending palatine artery, branch of facial artery that runs up the
superior pharyngeal constrictor muscle; supplies wall of pharynx & soft
palate
Ascending pharyngeal artery, branch of external carotid artery;
supplies wall of pharynx & soft palate

89. Veins of the palate are tributaries of the
pterygoid venous plexus
-Pterygoid plexus receives tributaries
corresponding with the branches of the
maxillary artery
-The pterygoid plexus of veins becomes
maxillary vein.
-Maxillary vein & superficial temporal vein
join to become retromandibular vein.
-Posterior branch of retromandibular vein &
posterior auricular vein then form the
external jugular vein, which empties into
the subclavian vein.
-Anterior branch of retromandibular vein &
facial vein form the common facial vein,
which empties into the internal jugular vein
Lymphatic drainage of the palate: to deep
cervical nodes

92. Cleft palate, cleft/bifid uvula, with or
without cleft lip:
•Unilateral
•Bilateral
•Median
-Diastrophic dwarfism
Paralysis of the soft palate
•pharyngeal isthmus can’t be closed
during swallowing & speech
•Causes food to enter the nasal cavity on
swallowing
•Causes difficult in producing explosive
consonants in speech
Angioedema of uvula (Quincke’s uvula):
•Surrounding the musculus uvula is the
loose CT of submucosa that is
responsible for great swelling of the
uvula secondary to angioedema
Pharyngeal
isthmus

93. Nasopalatine Block. Nasopalatine nerves can
be anesthetized by injecting anesthetic into
incisive fossa or foramen in hard palate. The
needle is inserted immediately posterior to
incisive papilla. Both nerves are anesthetized
by the same injection where they emerge
through the incisive fossa. The affected
tissues are the palatal mucosa, the lingual
gingivae and alveolar bone of the six anterior
maxillary teeth, and the hard palate.
Greater Palatine Block. Greater palatine
nerve can be anesthetized by injecting
anesthetic into greater palatine foramen. The
nerve emerges between the 2nd & 3rd molar
teeth. This nerve block anesthetizes all the
palatal mucosa & lingual gingivae posterior
to the maxillary canine teeth & the
underlying bone of the palate. Branches of
the greater palatine arteries should be
avoided. The anesthetic should be injected
slowly to prevent stripping of the mucosa
from the hard palate.

95. Chief functions of teeth:
•Incise, reduce, and mix food material with saliva during mastication (chewing).
•Help sustain themselves in the tooth sockets by assisting the development and
protection of the tissues that support them.
•Participate in articulation (distinct connected speech).
Major parts of a tooth:
a. The crown-the portion that protrudes above the gum line and is covered by
enamel.
b. The root-the portion that extends into the alveolus, surrounded by the gum, &
is covered by cementum.
Some terms used in dental/clinical practice
➢The vestibular surface (labial or buccal surface) of each tooth is directed
outwardly, and the lingual surface is directed inwardly
➢The mesial(proximal) surface of a tooth is directed toward the median plane
of the facial part of the cranium e.g. mesio-buccal root of the maxillary first
molar, mesio-lingual side of roots of 2
nd
& 3
rd
lower molars
➢The distal surface is directed away from the median plane
➢Both mesial and distal surfaces are contact surfaces, that is, surfaces that
contact adjacent teeth.
➢The masticatory surface is the occlusal surface.
Gross anatomy of the teeth

96. Classification of teeth:
➢A tooth is identified and described on the basis of its stage of development
whether it is deciduous(primary or temporary) or permanent(secondary),
➢The type of tooth, and its proximity to the midline or front of the mouth (e.g., medial
and lateral incisors; the 1st molar is anterior to the 2nd).
➢The types of teeth are identified by their physical characteristics:
-Incisors-thin cutting edges
-Canines-single prominent cones
-Premolars-bicuspids (two cusps)
-Molars-three or more cusps.
Deciduous (primary or temporary or baby or milk) teeth
•Occur in childhood
•Develop during the embryonic stage of development and erupt—that is, they
become visible in the mouth—during infancy.
•They are usually lost and replaced by permanent teeth
•There are 20 deciduous teeth: 4 incisors, 2 canines, & 4 molars in each jaw (424)
•Before eruption, developing teeth reside in alveolar arches as tooth buds
•They begin to erupt about 6 months after birth & have all erupted by the end of 2
years
•The teeth of the lower jaw (mandibular teeth) usually erupt (appear) before those
of the upper jaw (maxillary teeth)
•First teeth to erupt are the lower central incisor (erupt at 6-10 months after birth)
Gross anatomy of the teeth

97. Mandibular teeth
erupt first

98. Permanent (secondary or adult) teeth
•The second set of teeth formed in mammals
•They occur in adulthood
•There are 32 permanent teeth: 4 incisors, 2 canines, 4 premolars,
& 6 molars in each jaw (4246)
•They begin to erupt at 6 years of age
•The last tooth to erupt is the 3
rd
molar, which may happen
between the ages of 17 & 30 years
•Teeth of the lower jaw appear before those of the upper jaw
•Lower central incisors erupt first
Gross Anatomy of the Teeth cont’d

99. ➢A tooth has a crown,neck,&root
a.The crownprojects from the gingiva.
b.The neck is between the crown and the root.
c.The rootis fixed in the tooth socket by the
periodontium; number of roots varies.
➢Most of the tooth is composed of dentin, which is
covered by enamelover the crown and cement(L.
cementum) over the root.
➢The pulp cavity contains connective tissue, blood
vessels, and nerves.
➢The root canal (pulp canal) transmits the nerves and
vessels to and from the pulp cavity through the apical
foramen.
➢The tooth sockets are in the alveolar processes of the
maxillae and mandible and are the skeletal features
that display the greatest change during a lifetime.
➢Adjacent sockets are separated by interalveolar septa;
➢Within the socket, the roots of teeth with more than one
root are separated by interradicular septa.
Parts and Structure of the Teeth

100. ➢The bone of the socket has a thin cortex
separated from the adjacent labial and lingual
cortices by a variable amount of trabeculated
bone.
➢The labial wall of the socket is particularly thin
over the incisor teeth; the reverse is true for the
molars, where the lingual wall is thinner.
➢Thus the labial surface commonly is broken to
extract incisors and the lingual surface is broken
to extract molars.
➢The roots of the teeth are connected to the bone
of the alveolus by a springy suspension forming a
special type of fibrous joint called a dento-alveolar
syndesmosis or gomphosis. The periodontium
(periodontal membrane) is composed of
collagenous fibers that extend between the
cement of the root and the periosteum of the
alveolus. It is abundantly supplied with tactile,
pressoreceptivenerve endings, lymph capillaries,
and glomerular blood vessels that act as hydraulic
cushioning to curb axial masticatory pressure.
Pressoreceptivenerve endings are capable of
receiving changes in pressure as stimuli.
Parts and Structure of the Teeth cont’d

103. •The tooth lies in a bony socket, the alveolus, that is covered by
an oral mucosa, thegingiva (gum) that consists of,
a. keratinized stratified squamous epithelium
b. lamina propria of loose connective tissue that lies directly
adjacent to the bone of the alveolus.
•The tooth is made up of 4 major tissues: Tooth enamel, dentin,
cementum, & dental pulp
•The tooth consists of two major parts:
a. The crown-the portion that protrudes above the gum line
and is covered by enamel.
b. The root-the portion that extends into the alveolus & is
covered by cementum.
Histology of the teeth

104. The two major parts of the tooth
a. The crown-portion that protrudes
above the gum line and is covered by
enamel.
b. The root-portion that extends into
alveolus.
Internally, the tooth consists of a layer of
dentinthat surrounds a pulpconsisting
of loose connective tissue, nerves and
blood vessels.
In the dentin, directly adjacent to the pulp
is a layer of specialized cells called
odontoblasts-secrete organic matrix
that mineralizes and forms the dentin.
Histology of the teeth cont’d

105. Tooth and its
parts

106. Crown region
Dentin is covered by a layer of calcified organic matrix -theenamel
a. Hardest substance in body
b. Formed by cells called ameloblastsbefore tooth “erupts”from socket
c. Makes up the normally visible part of the tooth, covering the crown.
d. It is a very hard, white to off-white, highly mineralized substance that acts as a
barrier to protect the tooth but can become susceptible to degradation, especially by
acids from food and drink.
Root region
Dentin is covered by calcified organic matrix -thecementum –
a. Similar to bone, but no haversian system.
b. Excreted by cells called cementoblasts
Between the cementum and the bone of the socket lies the periodontal ligament
a. Consists of fibroblasts and collagen fibers with glycosaminoglycans in between
b. Forms cushion between tooth and bone
c. Attaches tooth to bone -Sharpey’s fibers
Histology of teeth cont’d

107. ➢The Trigeminal Nerve (CN V) has three sensory branches:
➢Ophthalmic branch (CN V1) supplies the orbit and forehead
➢Maxillarybranch (CN V2) supplies the maxillary sinus and
upper jaw teeth, gingiva, upper lip
➢Mandibularbranch (CN V3) supplies the tongue and the
lower jaw teeth, gingiva, periosteum of mandible
➢The named branches of the superior (CN V
2) and inferior(CN
V
3) alveolar nerves give rise to dental plexuses, the superior&
inferior dental plexuses, respectively that supply the maxillary
and mandibular teeth, respectively
➢The lingual nerve is closely related to the medial aspect of the
3
rd
molars, (more so the lower 3
rd
molar teeth); therefore,
caution is taken to avoid injuring this nerve during the
extraction of the 3
rd
molar teeth.

108. ➢Maxillary Teeth: Supplied by superior alveolarbranches of maxillary
branch (CN V2) of trigeminal nerve (CN V):
➢Anterior superior alveolar nerve oranterior superior dental/alveolar
branch (branch of infraorbital nerve from CN V2): supplies upper
incisors and canines
➢Middle superior alveolar nerves (from CN V2): supplies upper premolars
and the mesio-buccal root of the maxillary first molar
➢Posterior superior alveolar nerve orposterior superior alveolar/dental
branch (from CN V2): supplies upper molars except the mesio-buccal
root of the maxillary first molar
➢Mandibular Teeth: Supplied by branches of mandibular branch (CN V3)
of trigeminal nerve (CN V):
➢Inferior alveolar nerve (from CN V3): supplies mandibular teeth, gingiva
and lower lip unilaterally
➢Lingual nerve (from CN V3): anterior 2/3 of tongue and mucosa of the
floor of the mouth, lingual side of roots of 2
nd
& 3
rd
lower molars
➢Buccal nerve (from CN V3): gingiva on the buccal side of posterior teeth

112. The superior & inferior alveolar arteries, branches of the
maxillary artery, supply the maxillary & mandibular teeth,
respectively.
Alveolar veins with the same names & distribution accompany the
arteries.
➢Maxillary teeth: bysuperior alveolar branches of the 3
rd
part of maxillary
artery
➢Superior alveolar arteries:
-anterior superior alveolar artery (from infraorbital artery, branch of
3
rd
part of maxillary artery): supplies upper incisors & canines,
mucous membrane of maxillary sinus
-middle superior alveolar artery (branch of infraorbital artery)
-posterior superior alveolar artery orposterior dental artery (from 3
rd
part of Maxillary Artery): supplies molar & premolar teeth, gingiva,
lining of maxillary sinus
➢Mandibular teeth:
➢Inferior alveolar artery or inferior dental artery (branch of 1
st
part of
Maxillary Artery)

114. In this superficial dissection of the infratemporal region, most of the zygomatic arch and attached masseter, the coronoid process
and adjacent parts of the ramus of the mandible, and the inferior half of the temporal muscle have been removed. The first part
of the maxillary artery, the larger of the two end branches of the external carotid, run anteriorly, deep to the neck of the mandible
and then pass deeply between the lateral and the medial pterygoid muscles

115. Lymphatic vessels from the teeth and gingivae pass mainly to the submandibular
lymph nodes

116. Dental Caries, Pulpitis, and Tooth Abscesses
➢Decay of hard tissues of a tooth results in the formation of dental caries (cavities).
Treatment involves removal of the decayed tissue and restoration of the anatomy of
the tooth with a dental material.
➢Neglected dental caries eventually invade and inflame tissues in the pulp cavity.
Invasion of the pulp by a deep carious lesion results in infection and irritation of the
tissues (pulpitis)
➢Because the pulp cavity is a rigid space, the swollen tissues cause considerable pain
(toothache)
➢If untreated, the small vessels in the root canal may die from the pressure of the
swollen tissue, and the infected material may pass through the apical canal and
foramen into the periodontal tissues. An infective process develops and spreads
through the root canal to the alveolar bone, producing an abscess
➢Pus from an abscess of a maxillary molar tooth may extend into the nasal cavity or
the maxillary sinus. The roots of the maxillary molar teeth are closely related to the
floor of this sinus. As a consequence, infection of the pulp cavity may also cause
sinusitis or sinusitis may stimulate nerves entering the teeth and simulate a
toothache.

117. Extraction of the Teeth
➢Sometimes it is not practical to restore a tooth because of extreme tooth
destruction.
➢The only alternative is tooth extraction such as in following cases:
1. Trauma
➢A tooth may lose its blood supply as a result of trauma.
➢The blow to the tooth disrupts the blood vessels entering and leaving the
apical foramen.
➢It is not always possible to save the tooth.
2. Unerupted 3rd molars
➢are common dental problems
➢these teeth are the last to erupt, usually when people are in their late teens
or early 20s.
➢Often there is not enough room for these molars to erupt, and they become
lodged (impacted) under or against the 2nd molars
➢If impacted 3rd molars become painful, they are usually removed.
➢When doing so, the surgeon takes care not to injure the alveolar nerves.

119. Enamel hypoplasia Enamel hypocalcification

120. Assignment. Read about the following clinical correlates of teeth
What are tooth anomalies?
What systemic factors may be associated with enamel defects?
How do we estimate the age of a person using teeth?
What are the infections of teeth
How can medications affect teeth
What inherited diseases are associated with teeth?
Give examples of metabolic disorders that affect teeth
How can malnutrition affect teeth
What is the relationship between birth-related trauma and teeth
What is dentinogenesisimperfecta & explain how the condition causes
the patient to have translucent gray-yellow/brown teeth?
Define the following disorders related to teeth: a) Enamel hypoplasia
b) Rickets Fluorosis d) Hypercementosise) Enamel hypocalcification
The…………………………………….. nerve is closely related to the medial aspect
of the 3
rd
molar teeth, therefore, caution is taken to avoid injuring this
nerve during the extraction of the 3
rd
molar teeth.