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1. Parotid & Temporal Regions
Parotid and temporal regions, infratemporal fossa and temporomandibular joint;
Innervation of parotid gland and related structures; Muscles of mastication;
Neurovasculature of infratemporal fossa; Oral region, oral cavity; Lips, cheeks and
gingivae; Teeth; Hard and soft palate; Vasculature and innervation of palate; Tongue,
Muscles, innervation and vasculature of tongue; Salivary glands (pages 914-950)
Prep by:
Dr Victor Okika

2. Parotid Region
• The parotid region is the posterolateral part of the facial region, bounded by
the:
• Zygomatic arch superiorly.
• External ear and anterior border of the sternocleidomastoid posteriorly.
• Ramus of the mandible medially.
• Anterior border of the masseter muscle anteriorly.
• Angle and inferior border of the mandible inferiorly.
• The parotid region includes the parotid gland and duct, the parotid plexus
of the facial nerve (CN VII), the retromandibular vein, the external carotid
artery, and the masseter muscle.

3. Parotid Gland & Adjacent Structures
• The parotid gland is the largest of three paired salivary glands
• the parotid gland is usually examined with or immediately subsequent to
the dissection of the face to expose the facial nerve.
• Dissection of the parotid region must be completed before dissection of
the infratemporal region and muscles of mastication or the carotid
triangle of the neck.

4. Parotid Gland
• It is enclosed within a tough, unyielding, fascial capsule, the parotid
sheath (capsule), derived from the investing layer of deep cervical
fascia.
• Fatty tissue between the lobes of the gland confers the flexibility the
gland must have to accommodate the motion of the mandible.
• The apex of the parotid gland is posterior to the angle of the
mandible, and its base is related to the zygomatic arch.

6. Parotid Duct
• The parotid duct passes
horizontally from the
anterior edge of the
gland.
• At the anterior border of
the masseter, the duct
turns medially, pierces
the buccinator, and
enters the oral cavity
through a small orifice
opposite the 2nd
maxillary molar tooth.

7. Innervation of Parotid & Adjacent Structures
• Although the parotid plexus of CN VII is
embedded within the gland, it doesn't provide
innervation to the gland.
• The auriculotemporal nerve, a branch of CN V3,
passes superior to it with the superficial temporal
vessels.
• Along with the great auricular nerve, a branch of
the cervical plexus composed of fibers from C2
and C3 spinal nerves, innervates the parotid
sheath as well as the overlying skin.
• PNS component of the glossopharyngeal nerve
(CN IX) supplies presynpatic secretory fibers to
the otic ganglion.

8. • The postsynaptic parasympathetic fibers
are conveyed from the ganglion to the gland
by the auriculotemporal nerve.
• Stimulation of the parasympathetic fibers
produces a thin, watery saliva.
• Sympathetic fibers are derived from the
cervical ganglia through the external carotid
nerve plexus on the external carotid artery
• The vasomotor activity of these fibers may
reduce secretion from the gland.
• Sensory nerve fibers pass to the gland
through the great auricular and
auriculotemporal nerves.
Innervation of Parotid & Adjacent Structures

9. Temporal Region
• It’s the region of the head that includes the lateral area of the scalp
and the deeper soft tissues overlying the temporal fossa of the
cranium, superior to the zygomatic arch.
• The temporal fossa, occupied primarily by the upper portion of the
temporalis muscle, is bounded :
• Posteriorly and superiorly by the temporal lines.
• Anteriorly by the frontal and zygomatic bones.
• Laterally by the zygomatic arch.
• Inferiorly by the infratemporal crest.
• The floor of the temporal fossa is formed by parts of the four
bones that form the pterion.

10. Temporal Region
• The temporalis muscle arises from the bony floor
and the overlying temporal fascia which forms the
roof of the temporal fossa.
• This fascia covers the temporalis muscle, attaching
superiorly to the superior temporal line.
• Inferiorly, the fascia splits into two layers, which
attach to the lateral and medial surfaces of the
zygomatic arch.
• The temporal fascia also tethers the zygomatic arch
superiorly.
• When masseter muscle, which is attached to the
inferior border of the arch, contracts and exerts a
strong downward pull on the zygomatic arch, the
temporal fascia provides resistance.
Zygomatic arch

12. • It is an irregularly shaped space deep and inferior
to the zygomatic arch, deep to the ramus of the
mandible and posterior to the maxilla.
• It communicates with the temporal fossa through
the interval between (deep to) the zygomatic arch
and (superficial to) the cranial bones.
Infratemporal Fossa
• The boundaries of the infratemporal
fossa are as follows;
• Laterally: the ramus of the mandible.
• Medially: the lateral pterygoid plate.
• Anteriorly: the posterior aspect of the
maxilla.
• Posteriorly: the tympanic plate and the
mastoid and styloid processes of the
temporal bone
• Superiorly: the inferior (infratemporal)
surface of the greater wing of the
sphenoid.
• Inferiorly: where the medial pterygoid
muscle attaches to the mandible near its
angle.

13. Infratemporal Fossa
• The infratemporal fossa contains
• Inferior part of the temporalis muscle.
• Lateral and medial pterygoid muscles.
• Maxillary artery.
• Pterygoid venous plexus.
• Mandibular, inferior alveolar, lingual,
buccal, and chorda tympani nerves
• Otic ganglion.
• The parotid and temporal regions and
the infratemporal fossa collectively
include the temporomandibular joint
and the muscles of mastication that
produce its movements.

15. Temporomandibular Joint
• Is a modified hinge type of synovial joint
• permitting gliding (translation) and a small degree of rotation (pivoting) in addition
to flexion (elevation) and extension (depression) movements typical for hinge joints.
• Articulating bony surfaces are mandibular fossa and articular tubercle of the
temporal bone superiorly, and the head of the mandible inferiorly.
• The loose fibrous layer of the joint capsule attaches to the margins of the
articular cartilage on the temporal bone and around the neck of the mandible.
• The two bony articular surfaces are completely separated by intervening
fibrocartilage, the articular disc of the TMJ, attached at its periphery to the
internal aspect of the fibrous capsule.
• This creates separate superior and inferior articular cavities, or compartments, lined
by separate superior and inferior synovial membranes.

17. • 2 extrinsic ligaments and the lateral
ligament connect the mandible to the
cranium.
• The stylomandibular ligament, a thickening of
the fibrous capsule of the parotid gland, runs
from the styloid process to the angle of the
mandible. It does not contribute significantly to
the strength of the joint.
• The sphenomandibular ligament runs from the
spine of the sphenoid to the lingula of the
mandible.
NB: The sphenomandibular ligament is the
primary passive support of the mandible, although
the tonus of the muscles of mastication usually
bears the mandible’s weight.
Movements on the Temporomandibular Joint
• Gliding movements of protrusion
and retrusion (translation)
• between the temporal bone and the
articular disc (superior cavity)
• Hinge movements of depression
and elevation and the rotational or
pivoting movements
• occur in the inferior compartment.
• A thickened part of the joint
capsule forms the intrinsic lateral
ligament of the TMJ, which
strengthens the joint laterally
• With the postglenoid tubercle acts to
prevent posterior dislocation of the
joint.

18. Demonstrating the articular disc dividing the joint
cavity into superior and inferior compartments.
The sphenomandibular ligament passively bears
the weight of the lower jaw and is the “swinging
hinge” of the mandible, permitting protrusion
and retrusion as well as elevation & depression.

19. • When the mouth is closed and at rest, the heads of the mandible are held in the
retracted position in the mandibular fossae, and the chin is elevated by the tonus
of the retractors and elevators of the mandible
• When sleeping in the supine or sitting position (head upright), as one enters a
state of deep sleep, the tonic contraction relaxes and gravity causes depression of
the mandible (the mouth falls open).

21. Movements of the TMJ
• Translation: opening the mouth wider than just to separate the upper and lower
teeth, involves the head of the mandible and articular disc moving anteriorly on
the articular surface until the head lies inferior to the articular tubercle.
• If this occurs without depression, the chin protrudes.
• Most often, the mandible is depressed (the mouth is opened) as the head of the
mandible and articular disc glide toward the articular tubercle.
• Full depression possible only when the heads and discs are fully protracted.
• If protraction of head and disc occurs unilaterally, the contralateral head rotates
(pivots) on the inferior surface of the articular disc in the retracted position,
permitting simple side-to-side chewing or grinding movements over a small
range.
• During protrusion and retrusion of the mandible, the head and articular disc
slide anteriorly and posteriorly on the articular surface of the temporal bone,
with both sides moving together

22. Muscles of Mastication
• Four muscles: temporal, masseter, medial and lateral pterygoid muscles.
• Develop from the mesoderm of the embryonic first pharyngeal arch;
consequently are,
• Innervated by the nerve of that arch, the (motor root of the) mandibular nerve
(CN V3).

23. Muscles of mastication
• Generally, depression of the mandible is
produced by gravity
• The suprahyoid and infrahyoid muscles
are strap-like muscles on each side of
the neck & are primarily used to raise
and depress the hyoid bone and larynx,
respectively—e.g. during swallowing
• Indirectly they can also help depress the
mandible, especially when opening the
mouth suddenly, against resistance, or
when inverted (e.g., standing on one’s
head).
• The platysma can be similarly used.

26. Neurovasculature of Infratemporal fossa
• Maxillary artery: larger of the two terminal branches
of the external carotid artery.
• Arises posterior to the neck of the mandible and is divided
into three parts based on its relation to the lateral
pterygoid muscle.
• Pterygoid venous plexus: located partly between the
temporalis and the pterygoid muscle.
• Venous equivalent of most of the maxillary
artery—that is, most of the veins that accompany
the branches of the maxillary artery drain into this
plexus.
• Anastomoses anteriorly with the facial vein via the
deep facial vein and superiorly with the cavernous
sinus via emissary veins.

28. Neurovasculature of Infratemporal Fossa
• Mandibular nerve: arises from the
trigeminal ganglion in the middle
cranial fossa.
• It immediately receives the motor root
of the trigeminal nerve and descends
through the foramen ovale into the
infratemporal fossa.
• The branches of CN V3 are the
auriculotemporal, inferior alveolar,
lingual, and buccal nerves. Branches
of CN V3 also supply the four muscles
of mastication but not the buccinator,
which is supplied by the facial nerve.

29. Neurovasculature of Infratemporal Fossa
• Auriculotemporal nerve: encircles the middle
meningeal artery and divides into numerous
branches, the largest of which passes posteriorly,
medial to the neck of the mandible, and supplies
sensory fibers to the auricle and temporal region.
• Sends articular (sensory) fibers to the TMJ and
conveys postsynaptic parasympathetic secretomotor
fibers from the otic ganglion to the parotid gland.
• Inferior alveolar nerve: enters the mandibular
foramen and passes through the mandibular
canal, forming the inferior dental plexus, which
sends branches to all mandibular teeth on its
side. Another branch of the plexus, Mental
nerve: passes through the mental foramen and
supplies the skin and mucous membrane of the
lower lip, the skin of the chin, and the vestibular
gingiva of the mandibular incisor teeth.

30. Neurovasculature of Infratemporal Fossa
• Lingual nerve: lies anterior to the inferior alveolar nerve.
• sensory to the anterior two thirds of the tongue, the floor of the mouth, and the lingual
gingivae.
• It enters the mouth between the medial pterygoid muscle and the ramus of the
mandible and passes anteriorly under cover of the oral mucosa, just inferior to the 3rd
molar tooth.
• Chorda tympani nerve, a branch of CN VII carrying taste fibers from the
anterior two thirds of the tongue, joins the lingual nerve in the infratemporal
fossa.
• Also carries secretomotor fibers for the submandibular and sublingual salivary glands.
• Otic ganglion (PNS): located in the infratemporal fossa, just inferior to the
foramen ovale, medial to CN V3 and posterior to the medial pterygoid muscle.
• Presynaptic parasympathetic fibers, derived mainly from the glossopharyngeal nerve,
synapse in the otic ganglion.
• Postsynaptic parasympathetic fibers, which are secretory to the parotid gland, pass from
the otic ganglion to this gland through the auriculotemporal nerve.

31. Oral Region
• It 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 (L. lump).
• 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
involuntary (automatic) phase of swallowing occurs.

32. Oral Cavity
• The oral cavity (mouth) consists of two parts: the oral vestibule and the oral cavity
proper.
• The oral vestibule is the slit-like space between the teeth and gingivae (gums) and
the lips and cheeks.
• Communicates with the exterior through the oral fissure (opening).
• The size of the oral fissure is controlled by the circumoral muscles, such as the orbicularis oris
(the sphincter of the oral fissure), the buccinator, risorius, and depressors and elevators of the
lips (dilators of the fissure).
• The oral cavity proper is the space between the upper and the lower dental arches
or arcades (maxillary and mandibular alveolar arches and the teeth they bear).
• It is limited laterally and anteriorly by the dental arches.
• The roof of the oral cavity is formed by the palate.
• Posteriorly, the oral cavity communicates with the oropharynx (oral part of the
pharynx).
• When the mouth is closed and at rest, the oral cavity is fully occupied by the tongue.

33. Lips, Cheeks & Gingivae
• Lips: mobile, musculofibrous folds surrounding the
mouth, extending from the nasolabial sulci and
nares laterally and superiorly to the mentolabial
sulcus inferiorly.
• Contain the orbicularis oris and superior and inferior
labial muscles, vessels, and nerves.
• Covered externally by skin and internally by mucous
membrane.
• Function as the valves of the oral fissure, containing
the sphincter that controls entry and exit from the
mouth and upper alimentary and respiratory tracts.
• Used for grasping food, sucking liquids, keeping food
out of the vestibule, forming speech, and osculation
(kissing).
• The labial frenula are free-edged folds of mucous
membrane in the midline, extending from the
vestibular gingiva to the mucosa of the upper and
lower lips.

34. Blood Supply & Innervation
• Superior & inferior labial arteries : branches
of the facial arteries, anastomose with each
other in the lips to form an arterial ring.
• The pulse of these arteries may be palpated by
grasping the upper or lower lip lightly between
the first two digits.
• The upper lip is supplied by superior labial
branches of the facial and infra-orbital arteries (CN
V2)
• The lower lip is supplied by inferior labial
branches of the facial and mental arteries (CN V3).
• Lymph from the upper lip and lateral parts of
the lower lip passes primarily to the
submandibular lymph nodes whereas lymph
from the medial part of the lower lip passes
initially to the submental lymph nodes.

35. Cheeks
• They essentially have the same structure as the lips with which they are continuous.
• Form the movable walls of the oral cavity.
• Anatomically, the external aspect of the cheeks constitutes the buccal region,
bounded anteriorly by the oral and mental regions (lips and chin), superiorly by the
zygomatic region, posteriorly by the parotid region, and inferiorly by the inferior
border of the mandible.
• The prominence of the cheek occurs at the junction of the zygomatic and buccal
regions.
• The zygomatic bone underlying the prominence and the zygomatic arch, which
continues posteriorly, are commonly referred to as the “cheek bone”.
• The principal muscles of the cheeks are the buccinator.
• Superficial to the buccinators are encapsulated collections of fat; larger in infants
presumably to reinforce the cheeks and keep them from collapsing during sucking.
• The cheeks are supplied by buccal branches of the maxillary artery and innervated
by buccal branches of the mandibular nerve.

36. Gingivae
• Composed of fibrous tissue covered with mucous membrane.
• The gingiva proper is firmly attached to the alveolar processes of the mandible and maxilla and the necks of
the teeth.
• The gingiva proper adjacent to the tongue is the superior and inferior lingual gingivae, and that adjacent to
the lips and cheeks is the maxillary and mandibular labial or buccal gingiva, respectively.
• Gingiva proper is normally pink, stippled, and keratinizing.
• The alveolar mucosa (unattached gingiva) is normally shiny red and non-keratinizing.

37. Teeth
• The teeth lie in sockets (alveoli) in the gum-covered margins of
the mandible and maxilla.
• The teeth tear and grind the food, breaking it into smaller
fragments.
Dentition and Dental Formula
• Humans have two sets of teeth in their lifetime.
• By age 21,the primary dentition (deciduous teeth) is replaced
by the permanent dentition.
• From 6 months, the lower central incisors are first to appear.
Additional pairs erupt at varying intervals until all 20 emerge,
by 2 years.
• As the deep-lying permanent teeth enlarge and develop, the
roots of the deciduous teeth are resorbed until these teeth
loosen and fall out, typically between the 6 and 12 years.
• By the end of adolescence, all permanent teeth have erupted
except for the third molars (also called wisdom teeth), which
emerge between the ages of 17 and 25 years. There are 32
permanent teeth in a full set, but in some people the wisdom
teeth are either completely absent or fail to erupt.

38. Accessory Organs of the Digestive Tract - Teeth
• Teeth are classified according to their shape and function as incisors, canines,
premolars, or molars.
• The chisel-shaped incisors are adapted for nipping off pieces of food,
• The cone-shaped canines (cuspids, eyeteeth) tear and pierce.
• The premolars (bicuspids) and molars have broad crowns with rounded cusps
(surface bumps) for grinding food. The molars have four or five cusps and are
the best grinders.
• Upper and lower molars lock repeatedly in chewing, generating crushing forces
• Dental formula – for indicating number of teeth and relative positions, written
as a ratio of half of the uppers over lowers and multiplying by 2.

39. Tooth structure
• Each tooth has two main regions, the exposed crown
and the root(s) in the socket.
• The surface of the crown, is covered by a layer of hard
substance – enamel and is 0.96–1.6 mm thick.
• Enamel lacks cells and vessels and 99% of its mass
consists of densely packed hydroxyapatite crystals
arranged in force-resisting rods or prisms oriented
perpendicular to the tooth’s surface.
• Dentin or dentine is a bone like tissue with mineral
and collagen components, underlies the enamel cap
and forms the bulk of the tooth. Lacks blood vessels
and contains a unique radial striations called dentine
tubules.
• The pulp cavity, in the center of the tooth, is filled
with dental pulp, a loose connective tissue containing
the tooth’s vessels and nerves.
• Pulp supplies nutrients for the tooth’s hard tissues and
provides for tooth sensation. The part of the pulp
cavity in the root is the root canal. The opening into
the root canal at the tip of each root is the apical
foramen

40. Structure Of Teeth
• The tooth sockets are in the alveolar processes of the
maxillae and mandible.
• Adjacent sockets are separated by interalveolar
septa; within the socket, the roots of teeth with more
than one root are separated by interradicular septa.
• 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; in molars, the lingual wall is thinner.
• Roots: connected to the bone of the alveolus by
springy suspension fibrous joint called a dento-
alveolar syndesmosis or gomphosis
• Periodontium (periodontal membrane):contains
collagenous fibers that extend between the cement
of the root and the periosteum of the alveolus.
• supplied with tactile, pressoreceptive nerve endings, lymph
capillaries, and glomerular blood vessels that act as
hydraulic cushioning to curb axial masticatory pressure.

41. Vasculature & Innervation
• Superior and inferior alveolar arteries -
branches of the maxillary artery, supply the
maxillary and mandibular teeth, respectively.
• Alveolar veins with the same names and
distribution accompany the arteries.
• Lymphatic vessels from the teeth and gingivae
pass mainly to the submandibular lymph nodes.
• Branches of the superior (CN V2) and inferior
(CN V3) alveolar nerves give rise to dental
plexuses that supply the maxillary and
mandibular teeth.

42. Palate
• The palate forms the arched roof of the mouth and
the floor of the nasal cavities.
• Separates the oral cavity from the nasal cavities and
the nasopharynx, the part of the pharynx superior to
the soft palate.
• The superior (nasal) surface of the palate is covered
with respiratory mucosa, and the inferior (oral)
surface is covered with oral mucosa, densely packed
with glands.
• The palate consists of two regions: the hard palate
anteriorly and the soft palate posteriorly.

43. Hard Palate
• Anterior two thirds of the palate has a bony
skeleton formed by the palatine processes of the
maxillae and the horizontal plates of the
palatine bones.
• The incisive fossa is a depression in the midline
of the bony palate posterior to the central incisor
teeth into which the incisive canals open.
• The nasopalatine nerves pass from the nose
through a variable number of incisive canals and
foramina that open into the incisive fossa.
• Medial to the 3rd molar tooth, the greater
palatine foramen pierces the lateral border of
the bony palate from which the greater palatine
vessels and nerve emerge.
• The lesser palatine foramina posterior to the
greater palatine foramen pierce the pyramidal
process of the palatine bone and transmit the
lesser palatine nerves and vessels to the soft
palate and adjacent structures

44. Soft Palate
• Is a movable posterior third of the palate and is suspended from the posterior
border of the hard palate.
• Has no bony skeleton; anteriorly strengthened by the palatine aponeurosis, which
attaches to the posterior edge of the hard palate.
• Posteroinferiorly, the soft palate has a curved free margin from which hangs a
conical process, the uvula.
• During swallowing , the soft palate initially is tensed to allow the tongue to press
against it, squeezing the bolus of food to the back of the mouth. The soft palate is
then elevated posteriorly and superiorly against the wall of the pharynx, thereby
preventing passage of food into the nasal cavity.
• Laterally, the soft palate is continuous with the wall of the pharynx and is joined to
the tongue and pharynx by the palatoglossal and palatopharyngeal arches,
respectively.
• Few taste buds are located in the epithelium covering the oral surface of the soft
palate, the posterior wall of the oropharynx, and the epiglottis.

45. • Palatine tonsils : masses of lymphoid
tissue, one on each side of the
oropharynx. Each tonsil is in a tonsillar
fossa (sinus), bounded by the
palatoglossal and palatopharyngeal
arches and the tongue.
Soft Palate
• Fauces: Is the space between the
cavity of the mouth and the pharynx.
• The isthmus of the fauces is the
short constricted space that
establishes the connection between
the oral cavity proper and the
oropharynx.

46. • Palatine raphe: narrowish white streak,
posteriorly in the midline of the palate from
the incisive papilla. It marks the site of fusion
of the embryonic palatal processes (palatal
shelves).
Superficial Features of the Palate
• Mucosa of the hard palate is tightly
bound to the underlying bone.
• Superior lingual gingiva, is continuous
with the mucosa of the palate.
• 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.
• Gives orange-pink color
• Posterior to the maxillary incisor teeth,
is the incisive papilla.
• Tranverse palatine folds: arise laterally
from the incisive papilla.
• Assist with manipulation of food during
mastication.

47. • The sensory nerves - branches of the maxillary
nerve (CNV2), from the pterygopalatine
ganglion.
• The greater palatine nerve supplies the
gingivae, mucous membrane, and glands of
most of the hard palate.
• The nasopalatine nerve supplies the mucous
membrane of the anterior part of the hard
palate.
• The lesser palatine nerves supply supply the
soft palate.
• The palatine nerves accompany the arteries
through the greater and lesser palatine
foramina, respectively.
• Except for the tensor veli palatini supplied by
CN V2, all muscles of the soft palate are
supplied through the pharyngeal plexus of
nerves
Blood Supply of Palate
• Blood supply mainly from the greater
palatine artery on each side, a branch of
the descending palatine artery.
• The greater palatine artery passes through
the greater palatine foramen and runs
anteromedially.
• The lesser palatine artery, a smaller branch
of the descending palatine artery, enters
the palate through the lesser palatine
foramen and anastomoses with the
ascending palatine artery, a branch of the
facial artery.
• The veins of the palate are tributaries of
the pterygoid venous plexus.
Nerve Supply of Palate

51. Tongue
• mobile muscular organ.
• Partly in the oral cavity and partly in the oropharynx.
• Functions in articulation (forming words during
speaking) and squeezing food into the oropharynx
as part of deglutition, mastication, taste and oral
cleansing.
• 3 parts : root, body and apex.
• Root : is the attached posterior portion extending
between the mandible, hyoid, and the nearly
vertical posterior surface of the tongue.
• body: Is the anterior, approximately two thirds of
the tongue between root and apex.
• Apex (tip): Is the anterior end of the body, which
rests against the incisor teeth.
• The body and apex of the tongue are extremely mobile.

52. Tongue
• It has 2 surfaces which are;
1. The more extensive, superior and posterior surface is the dorsum of the
tongue.
2. The inferior surface of the tongue, usually rests against the floor of the
mouth, ”underside”.
• The dorsum of the tongue is characterized by a V-shaped groove, the terminal
sulcus, the angle of which points posteriorly to the foramen cecum.
• The terminal sulcus divides the dorsum of the tongue transversely into a presulcal
anterior part in the oral cavity proper and a postsulcal posterior part in the
oropharynx.
• A midline groove divides the anterior part of the tongue into right and left
parts.
• The mucous membrane on the anterior part of the tongue is relatively thin and
closely attached to the underlying muscle.
• Rough texture because of the presence of numerous small lingual papillae:

53. • Filiform papillae: long and numerous,
contain afferent nerve endings that are
sensitive to touch, are scaly, conical
projections, pinkish gray and are
arranged in V-shaped rows that are
parallel to the terminal sulcus, except at
the apex, where they tend to be
arranged transversely.
Lingual Papillae
• Vallate papillae: large and flat topped,
lie directly anterior to the terminal
sulcus and are arranged in a V-shaped
row, surrounded by deep circular
trenches, walls embedded with taste
buds.
• Foliate papillae: small lateral folds of
the lingual mucosa, poorly developed in
humans.
• Fungiform papillae: mushroom shaped
pink or red spots scattered among the
filiform papillae but are most numerous
at the apex and margins of the tongue.
The vallate, foliate, and most of the fungiform papillae
contain taste receptors in the taste buds.

54. Tongue
• Mucous membrane of the posterior part of the
tongue is thicker and freely movable and has no
lingual papillae, but the underlying lymphoid nodules
(lingual tonsil) give this part of the tongue an
irregular, cobblestone appearance.
• The pharyngeal part of the tongue constitutes the
anterior wall of the oropharynx.
• The inferior surface of the tongue is covered with a
thin, transparent mucous membrane, connected to
the floor of the mouth by a midline fold called the
frenulum of the tongue.
• On each side of the frenulum, a deep lingual vein is
visible through the thin mucous membrane on each
side of frenulum
• 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.

55. Tongue Muscles
• The intrinsic muscles, are confined within the tongue and
are not attached to bone and change the shape of the
tongue but not it’s position e.g. rolling the tongue.
• The extrinsic muscles extend to the tongue from bones of
the skull and the hyoid bone and alter the position of the
tongue; protrude it, retract it, and move it laterally.
• The four intrinsic and four extrinsic muscles in each half of
the tongue are separated by a median fibrous lingual
septum, which merges posteriorly with the lingual
aponeurosis.
• The superior and inferior longitudinal muscles act
together to make the tongue short and thick and to retract
the protruded tongue.
• The transverse and vertical muscles act simultaneously to
make the tongue long and narrow, also to 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.

59. • The chorda tympani joins the lingual
nerve in the infratemporal fossa and
runs anteriorly in its sheath.
Innervation of Tongue
• All muscles of the tongue, except the
palatoglossus receive motor innervation
from CN XII, the hypoglossal nerve.
• Palatoglossus muscle - supplied by the
pharyngeal plexus.
• For general sensation (touch and
temperature), the mucosa of the anterior
two thirds of the tongue is supplied by the
lingual nerve, a branch of CN V3.
• For special sensation (taste), this part of the
tongue, except for the vallate papillae, is
supplied through the chorda tympani nerve,
a branch of CN VII.

60. Innervation of the Tongue
• The mucous membrane of the
posterior third of the tongue and the
vallate papillae are supplied by the
lingual branch of the glossopharyngeal
nerve (CN IX) for both general and
special sensation.
• Four basic taste sensations: sweet,
salty, sour, and bitter. Sweetness is
detected at the apex, saltiness at the
lateral margins, and sourness and
bitterness at the posterior part of the
tongue.

61. Blood Supply of Tongue
• The Lingual artery supplies the tongue, its a
branch of the external carotid artery.
• The dorsal lingual arteries supply the root of
the tongue; the deep lingual arteries supply
the body.
• The dorsal lingual arteries are prevented from
communicating by the lingual septum
whereas the deep lingual arteries freely
communicate with each other near the apex
of the tongue.
• The veins of the tongue are the dorsal lingual
veins, which accompanies the lingual artery;
the deep lingual veins, which begin at the
apex of the tongue, run posteriorly beside the
lingual frenulum to join the sublingual vein.

62. Lymphatic Drainage
• Most of the lymphatic drainage converges toward
and follows the venous drainage
• however, lymph from the tip of the tongue, frenulum,
and central lower lip runs an independent course
• Lymph from the tongue takes four routes:
• Lymph from the root drains bilaterally into the superior
deep cervical lymph nodes.
• Lymph from the medial part of the body drains bilaterally
and directly to the inferior deep cervical lymph nodes.
• Lymph from the right and left lateral parts of body drains
to the submandibular lymph nodes on the ipsilateral
side.
• The apex and frenulum drain to the submental lymph
nodes, the medial portion draining bilaterally.
• All lymph from the tongue ultimately drains to the
deep cervical nodes, and passes via the jugular
venous trunks into the venous system at the right
and left venous angles.

63. Salivary Glands
• The salivary glands are the parotid, submandibular, and sublingual glands.
• Saliva is a clear, tasteless, odorless viscid fluid secreted by salivary and
mucous glands.
• Keeps the mucous membrane of the mouth moist.
• Lubricates the food during mastication.
• Begins the digestion of starches.
• Serves as an intrinsic “mouthwash.”
• Plays significant roles in the prevention of tooth decay and in the ability to taste.
• In addition to the main salivary glands, small accessory salivary glands are
scattered over the palate, lips, cheeks, tonsils, and tongue

64. Submandibular Gland
• Lie along the body of the mandible, partly superior and partly inferior to the
posterior half of the mandible, and partly superficial and partly deep to the
mylohyoid muscle.
• The submandibular duct, approximately 5 cm long, arises from the portion
of the gland that lies between the mylohyoid and the hyoglossus muscles.
• Passing from lateral to medial, the lingual nerve loops under the duct that
runs anteriorly, opening by one to three orifices on a small sublingual papilla
beside the base of the lingual frenulum.
• The orifices of the submandibular ducts are visible, and saliva can often be
seen trickling from them (or spraying from them during yawning).

66. Vasculature & Innervation of Submandibular
Gland
• The arterial supply of the submandibular glands is from the submental
arteries.
• The veins accompany the arteries.
• The lymphatic vessels of the glands end in the deep cervical lymph nodes,
particularly the jugulo-omohyoid node.
• The submandibular glands are supplied by presynaptic parasympathetic
secretomotor fibers conveyed from the facial nerve to the lingual nerve by
the chorda tympani nerve, which synapse with postsynaptic neurons in the
submandibular ganglion. The latter fibers accompany arteries to reach the
gland, along with vasoconstrictive postsynaptic sympathetic fibers from the
superior cervical ganglion.

68. Sublingual Glands
• smallest and most deeply situated of the salivary
glands.
• almond-shaped gland, lies in the floor of the
mouth between the mandible and the
genioglossus muscle.
• The glands from each side unite to form a
horseshoe-shaped mass around the connective
tissue core of the lingual frenulum.
• Numerous small sublingual ducts open into the
floor of the mouth along the sublingual folds.
• The arterial supply of the sublingual glands is from
the sublingual and submental arteries, branches of
the lingual and facial arteries, respectively.
• The nerves of the glands accompany those of the
submandibular gland. Presynaptic
parasympathetic secretomotor fibers are conveyed
by the facial, chorda tympani, and lingual nerves
to synapse in the submandibular ganglion

69. FYL
• Because the branches of the
facial nerve run through the
parotid gland on their way to
the muscles of facial expression,
surgery on this gland can lead to
facial paralysis.