3. 3
EmbryologyEmbryology
• The major salivary glands develop from theThe major salivary glands develop from the
6th-8th weeks of gestation as outpouchings6th-8th weeks of gestation as outpouchings
of oral ectoderm into the surroundingof oral ectoderm into the surrounding
mesenchyme.mesenchyme.
• The parotid develops first, growingThe parotid develops first, growing
posteriorly as the facial nerve advancesposteriorly as the facial nerve advances
anteriorly; eventually, the fully developedanteriorly; eventually, the fully developed
parotid surrounds VII.parotid surrounds VII.
• However, the Parotid is the last to becomeHowever, the Parotid is the last to become
encapsulated, after the lymphatics develop,encapsulated, after the lymphatics develop,
resulting in its unique anatomy withresulting in its unique anatomy with
entrapment of lymphatics in the parenchymaentrapment of lymphatics in the parenchyma
of the glandof the gland
4. 4
• Salivary epithelial cells are oftenSalivary epithelial cells are often
included within these lymph nodes,included within these lymph nodes,
leading to development of Warthin’sleading to development of Warthin’s
tumors and Lymphoepithelial cyststumors and Lymphoepithelial cysts
within the Parotid gland.within the Parotid gland.
• The other major salivary glands doThe other major salivary glands do
NOT have intraparenchymal lymphNOT have intraparenchymal lymph
nodes.nodes.
5. 5
Function of SalivaFunction of Saliva
At least 8 major functions of saliva have been identified:At least 8 major functions of saliva have been identified:
1) Moistens oral mucosa. Mucin layer is the most important1) Moistens oral mucosa. Mucin layer is the most important
nonimmune defense mechanism in the oral cavity.nonimmune defense mechanism in the oral cavity.
2) Moistens dry food and cools hot food.2) Moistens dry food and cools hot food.
3) A medium for dissolved foods to stimulate the taste buds.3) A medium for dissolved foods to stimulate the taste buds.
4) Buffers oral cavity contents due to high concentration of4) Buffers oral cavity contents due to high concentration of
bicarbonate ions.bicarbonate ions.
5) Digestion. Alpha-amylase, contained in saliva, breaks 1-45) Digestion. Alpha-amylase, contained in saliva, breaks 1-4
glycoside bonds, while lingual lipase helps break down fats.glycoside bonds, while lingual lipase helps break down fats.
6) Controls bacterial flora of the oral cavity.6) Controls bacterial flora of the oral cavity.
7) Mineralization of new teeth and repair of precarious enamel7) Mineralization of new teeth and repair of precarious enamel
lesions. Saliva is high in calcium and phosphate.lesions. Saliva is high in calcium and phosphate.
8) Protects the teeth. This signifies a saliva protein coat on the8) Protects the teeth. This signifies a saliva protein coat on the
teeth which contains antibacterial compounds. Thus, salivaryteeth which contains antibacterial compounds. Thus, salivary
hypofunction results in dental caries.hypofunction results in dental caries.
6. 6
The intraoral complications ofThe intraoral complications of
salivary hypofunctionsalivary hypofunction
• 1) Candidiasis1) Candidiasis
• 2) Oral Lichen Planus (usually painful)2) Oral Lichen Planus (usually painful)
• 3) Burning Mouth Syndrome (normal appearing oral mucosa with a3) Burning Mouth Syndrome (normal appearing oral mucosa with a
subjective sensation of burning)subjective sensation of burning)
• 4) Recurrent aphthous ulcers4) Recurrent aphthous ulcers
• 5) Dental caries.5) Dental caries.
• The best way to evaluate salivary function is to measure the salivaryThe best way to evaluate salivary function is to measure the salivary
flow rate in stimulated (e.g., by using a parasympathomimetic asflow rate in stimulated (e.g., by using a parasympathomimetic as
pilocarpine) and unstimulated states. Xerostomia is NOT a reliablepilocarpine) and unstimulated states. Xerostomia is NOT a reliable
indicator of salivary hypofunction.indicator of salivary hypofunction.
• Stimulation results in an increase in total salivary flow from 0.3 cc/minStimulation results in an increase in total salivary flow from 0.3 cc/min
to >1 cc/min. The salivary response is directly related to a subject’sto >1 cc/min. The salivary response is directly related to a subject’s
state of hungerstate of hunger
7. 7
The Parotid GlandThe Parotid Gland
• The largest salivary glandThe largest salivary gland
• Lies wedge-shaped between the mandibleLies wedge-shaped between the mandible
and sternomastoid and over bothand sternomastoid and over both
• Relations:Relations:
• Above: external auditory meats and temporo-Above: external auditory meats and temporo-
mandibular jointmandibular joint
• Below: post belly digastricBelow: post belly digastric
• Anteriorly: mandible and masseterAnteriorly: mandible and masseter
• Medially: styloid process and its musclesMedially: styloid process and its muscles
8. 8
Structures at the Angle of theStructures at the Angle of the
MandibleMandible
• Medial relations of the parotid: theMedial relations of the parotid: the
styloid process and its musclesstyloid process and its muscles
separate the gland from theseparate the gland from the
• internal jugular veininternal jugular vein
• Internal carotid arteryInternal carotid artery
• The last four cranial nervesThe last four cranial nerves
• Lateral wall of the pharynxLateral wall of the pharynx
12. 12
FasciaFascia
• The parotid is enclosed in a split in theThe parotid is enclosed in a split in the
investing fasciainvesting fascia
• The parotid lymph nodes lie both onThe parotid lymph nodes lie both on
and below the parotid glandand below the parotid gland
• Antero-inferiorly, the fascia isAntero-inferiorly, the fascia is
thickened to form the stylomandibularthickened to form the stylomandibular
ligament; the only structure thatligament; the only structure that
separates the parotid from theseparates the parotid from the
submandibular glandssubmandibular glands
13. 13
The Facial NerveThe Facial Nerve
• The parotid gland is divided into superficialThe parotid gland is divided into superficial
and deep lobes by three structuresand deep lobes by three structures
traversing the gland:traversing the gland:
• The Facial NerveThe Facial Nerve
• The retromandibular vein (post facial) formedThe retromandibular vein (post facial) formed
by the superficial temporal and maxillaryby the superficial temporal and maxillary
• The external carotid artery dividing at theThe external carotid artery dividing at the
neck of the mandible into the superficialneck of the mandible into the superficial
temporal and maxillarytemporal and maxillary
14. 14
Relation of the Facial Nerve andRelation of the Facial Nerve and
ParotidParotid
• The parotid develops in the crotchThe parotid develops in the crotch
formed by the 2 divisions of the facialformed by the 2 divisions of the facial
nervenerve
• As it enlarges it overlaps the nerveAs it enlarges it overlaps the nerve
trunks, the superficial and deep partstrunks, the superficial and deep parts
fuse and the nerve becomes buriedfuse and the nerve becomes buried
within the gland.within the gland.
16. 16
The Facial NerveThe Facial Nerve
• Emerges from the stylomastoid foramenEmerges from the stylomastoid foramen
• Winds laterally to the styloid processWinds laterally to the styloid process
• Surgical ExposureSurgical Exposure
• In the inverted V between the bony externalIn the inverted V between the bony external
auditory meatus and the mastoid processauditory meatus and the mastoid process
• Just beyond the point the nerve dives intoJust beyond the point the nerve dives into
the post aspect of the parotid and bifurcatesthe post aspect of the parotid and bifurcates
almost immediately into its two mainalmost immediately into its two main
divisionsdivisions
17. 17
Branches of the Facial NBranches of the Facial N
• The nerve then gives rise to 2 divisions:The nerve then gives rise to 2 divisions:
• 1) Temperofacial (upper)1) Temperofacial (upper)
• 2) Cervicofacial (lower)2) Cervicofacial (lower)
• Followed by 5 terminal branches:Followed by 5 terminal branches:
• 1) Temporal1) Temporal
• 2) Zygomatic2) Zygomatic
• 3) Buccal3) Buccal
• 4) Marginal Mandibular4) Marginal Mandibular
• 5) Cervical5) Cervical
18. 18
BranchesBranches
• The two divisions may be completelyThe two divisions may be completely
separate, may form a plexus ofseparate, may form a plexus of
intermingling fibers, or may formintermingling fibers, or may form
cross-communications that be dividedcross-communications that be divided
safely during dissectionsafely during dissection
19. 19
Nerve InjuryNerve Injury
• Clinical examination of the Parotid shouldClinical examination of the Parotid should
include examination of the Facial nerveinclude examination of the Facial nerve
• Malignant tumors of the parotid may involveMalignant tumors of the parotid may involve
VII and cause facial palsy, while benignVII and cause facial palsy, while benign
tumors never affect VIItumors never affect VII
• During Superficial Parotidectomy, the nerveDuring Superficial Parotidectomy, the nerve
is exposed posteriorly in the space betweenis exposed posteriorly in the space between
the bony canal of external auditory meatusthe bony canal of external auditory meatus
and the mastoid processand the mastoid process
• It is then traced anteriorly into the gland toIt is then traced anteriorly into the gland to
divide the gland superficial and deep bydivide the gland superficial and deep by
nerve branchesnerve branches
20. 20
The Parotid DuctThe Parotid Duct
• Stensen’s duct is 5 cm long.Stensen’s duct is 5 cm long.
• Arises from the anterior part of theArises from the anterior part of the
gland and runs over the masseter onegland and runs over the masseter one
finger below the zygomatic arch tofinger below the zygomatic arch to
pierce the buccinator and openpierce the buccinator and open
opposite the second upper molar toothopposite the second upper molar tooth
21. 21
Parotid Duct orificeParotid Duct orifice
• Clinical examination of the parotidClinical examination of the parotid
gland should include examination ofgland should include examination of
the duct orifice opposite the upper 2the duct orifice opposite the upper 2ndnd
molar for signs of inflammation, andmolar for signs of inflammation, and
palpated for stonepalpated for stone
• Parotid Sialogram is performed byParotid Sialogram is performed by
injecting a contrast through a canulainjecting a contrast through a canula
placed in the orifice of the ductplaced in the orifice of the duct
23. 23
Submandibular GlandSubmandibular Gland
• Large superficial lobe and a small deepLarge superficial lobe and a small deep
lobe, that connect around thelobe, that connect around the
mylohyoidmylohyoid
• Superficial lobe lies at the angle of theSuperficial lobe lies at the angle of the
Jaw, wedged bet the mandible andJaw, wedged bet the mandible and
mylohyoid and overlapping themylohyoid and overlapping the
digastricdigastric
25. 25
Superficial and DeepSuperficial and Deep
RelationsRelations
• Superficially:Superficially: The skin, the platysma, theThe skin, the platysma, the
capsule (deep fascia), the cervical branch ofcapsule (deep fascia), the cervical branch of
Facial Nerve, and the Facial VeinFacial Nerve, and the Facial Vein
• Deeply:Deeply: the deep aspect lies against thethe deep aspect lies against the
mylohyoid for the most part. But posteriorlymylohyoid for the most part. But posteriorly
lies on the hyoglossus and comes in contactlies on the hyoglossus and comes in contact
with the lingual and hypoglossal nerves.with the lingual and hypoglossal nerves.
• Both nerves lie on the hyoglossus as theyBoth nerves lie on the hyoglossus as they
pass forward to the tonguepass forward to the tongue
26. 26
The facial ArteryThe facial Artery
• PosteriorPosterior
• Arches over itsArches over its
superior aspect tosuperior aspect to
reach inferiorreach inferior
border of theborder of the
mandible andmandible and
then ascends onthen ascends on
to the face in frontto the face in front
of the masseterof the masseter
28. 28
The Submandibular DuctThe Submandibular Duct
• Arises from the deep part of the gland, runsArises from the deep part of the gland, runs
forward to open at the side of the frenulumforward to open at the side of the frenulum
linguaelinguae
• Lies beneath the mucosa of the floor of theLies beneath the mucosa of the floor of the
mouth along the side of the tonguemouth along the side of the tongue
• Lingual nerve loops around the duct, double-Lingual nerve loops around the duct, double-
crossing it, by passing from lateral beneath,crossing it, by passing from lateral beneath,
then medialthen medial
• The sublingual salivary gland is also medialThe sublingual salivary gland is also medial
to the duct.to the duct.
29. 29
Clinical ApplicationsClinical Applications
• Submandibular LN are adherent to the glandSubmandibular LN are adherent to the gland
and partly between it and the mandibleand partly between it and the mandible
• Differentiating bet submandibular LN andDifferentiating bet submandibular LN and
Salivary gland:Salivary gland:
• The salivary gland can be palpatedThe salivary gland can be palpated
bimanually as it extends into the floor of thebimanually as it extends into the floor of the
mouth.mouth.
• The Lymph Nodes are only felt below theThe Lymph Nodes are only felt below the
mandible.mandible.
• LN may be multiple and a space separatesLN may be multiple and a space separates
them from the mandiblethem from the mandible
30. 30
Clinical ApplicationsClinical Applications
• A stone in the submandibular duct canA stone in the submandibular duct can
be felt bimanually in the floor of thebe felt bimanually in the floor of the
mouth and can be seen if largemouth and can be seen if large
• The presence of LN adherent to theThe presence of LN adherent to the
gland makes removal of the gland partgland makes removal of the gland part
of block neck dissectionof block neck dissection
31. 31
Autonomic InnervationsAutonomic Innervations
• Parasympathetic Stimulation results in abundant,Parasympathetic Stimulation results in abundant,
watery saliva with a decrease in [amylase] in salivawatery saliva with a decrease in [amylase] in saliva
and an increase in [amylase] in the serum.and an increase in [amylase] in the serum.
Acetylcholine is the active neurotransmitter, bindingAcetylcholine is the active neurotransmitter, binding
at muscarinic receptors in the salivary glands. Theat muscarinic receptors in the salivary glands. The
parasympathetic nervous system is the primaryparasympathetic nervous system is the primary
instigator of salivary secretion.instigator of salivary secretion.
• Parasympathetic Interruption to salivary glandsParasympathetic Interruption to salivary glands
results in atrophy, while sympathetic interruptionresults in atrophy, while sympathetic interruption
doesn’t cause a significant change.doesn’t cause a significant change.
• It was once thought that the sympathetic nervousIt was once thought that the sympathetic nervous
system antagonizes the parasympathetic nervoussystem antagonizes the parasympathetic nervous
system, but this is now known not to be truesystem, but this is now known not to be true
32. 32
Autonomic InnervationAutonomic Innervation
• In the case of the parotid,In the case of the parotid,
parasympathetic fibers originate fromparasympathetic fibers originate from
CN IXCN IX
• In the case of the Submandibular andIn the case of the Submandibular and
Sublingual glands, the parasympatheticSublingual glands, the parasympathetic
fibers originate in CN VIIfibers originate in CN VII
33. 33
Sympathetic InnervationSympathetic Innervation
• Stimulation by the sympathetic nervous systemStimulation by the sympathetic nervous system
results in a scant, viscous saliva rich in solutes withresults in a scant, viscous saliva rich in solutes with
an increase in [amylase] in the saliva and no changean increase in [amylase] in the saliva and no change
in [amylase] in the serum.in [amylase] in the serum.
• For all of the salivary glands, these fibers originateFor all of the salivary glands, these fibers originate
in the Superior Cervical ganglion and travel within the Superior Cervical ganglion and travel with
arteries to reach the glands:arteries to reach the glands:
• 1) External Carotid artery for the Parotid1) External Carotid artery for the Parotid
• 2) Lingual artery for the Submandibular, and2) Lingual artery for the Submandibular, and
• 3) Facial artery in the case of the Sublingual.3) Facial artery in the case of the Sublingual.
34. 34
The Most Common TumorsThe Most Common Tumors
• Histologically, salivary gland tumors are theHistologically, salivary gland tumors are the
most heterogenous group of tumors of anymost heterogenous group of tumors of any
tissue in the bodytissue in the body
• Of salivary gland neoplasms, >50% areOf salivary gland neoplasms, >50% are
benignbenign
• Approximately 70% to 80% of all salivaryApproximately 70% to 80% of all salivary
gland neoplasms originate in the parotidgland neoplasms originate in the parotid
• The palate is the most common site of minorThe palate is the most common site of minor
salivary gland tumorssalivary gland tumors
• The frequency of malignant lesions variesThe frequency of malignant lesions varies
by site.by site.
35. 35
Malignant TumorsMalignant Tumors
• Approximately 20-25% of parotid, 35-40% ofApproximately 20-25% of parotid, 35-40% of
submandibular tumors, 50% of palate tumors, and >submandibular tumors, 50% of palate tumors, and >
90% of sublingual gland tumors are malignant90% of sublingual gland tumors are malignant
• The most common benign salivary tumor isThe most common benign salivary tumor is
pleomorphic adenoma, comprising 50% of allpleomorphic adenoma, comprising 50% of all
salivary tumors and 65% of parotid gland tumorssalivary tumors and 65% of parotid gland tumors
• The most common malignant salivary tumor is theThe most common malignant salivary tumor is the
mucoepidermoid carcinoma,mucoepidermoid carcinoma, comprising 10% of allcomprising 10% of all
salivary gland neoplasms and 35% of malignantsalivary gland neoplasms and 35% of malignant
salivary gland neoplasms, occurring most often insalivary gland neoplasms, occurring most often in
the parotid gland.the parotid gland.
37. 37
Q & AQ & A
1- Mark following statements as true (T) or false (F):1- Mark following statements as true (T) or false (F):
A-The Parotid gland is the last to be encapsulatedA-The Parotid gland is the last to be encapsulated
B-The Parotid gland has intraparenchymal lymphaticsB-The Parotid gland has intraparenchymal lymphatics
C- The hypoglossal nerve divides the parotid gland intoC- The hypoglossal nerve divides the parotid gland into
superficial and deep lobessuperficial and deep lobes
D-The parotid duct opens in the floor of the mouthD-The parotid duct opens in the floor of the mouth
E-The parotid secretion is mucus and viscousE-The parotid secretion is mucus and viscous
38. 38
Q 2Q 2
2- Mark following statements as true (T) or false (F):2- Mark following statements as true (T) or false (F):
A-The Parotid gland is separated from theA-The Parotid gland is separated from the
submandibular gland by the stylomastoid ligamentsubmandibular gland by the stylomastoid ligament
B- Benign tumors of the parotid may cause facial neverB- Benign tumors of the parotid may cause facial never
palsypalsy
C- The facial Nerve divides into 2 trunks, each giving 3C- The facial Nerve divides into 2 trunks, each giving 3
branchesbranches
D- The superficial and deep lobes of the parotid glandD- The superficial and deep lobes of the parotid gland
are completely separated by the facial nerveare completely separated by the facial nerve
E- The facial nerve trunk may be injured duringE- The facial nerve trunk may be injured during
superficial parotidectomysuperficial parotidectomy
39. 39
Q 3Q 3
3-Mark following statements as true (T) or false (F):3-Mark following statements as true (T) or false (F):
A-The submandibular gland consists of a large deepA-The submandibular gland consists of a large deep
lobe and a small superficial lobelobe and a small superficial lobe
B-Both lobes of the submandibular gland are separatedB-Both lobes of the submandibular gland are separated
by the facial nerveby the facial nerve
C-Salivary stones form more commonly in theC-Salivary stones form more commonly in the
submandibular ductsubmandibular duct
D-Submandibular sialadenectomy is part of block neckD-Submandibular sialadenectomy is part of block neck
dissectiondissection
E-Hypoglossal N runs below the deep part of theE-Hypoglossal N runs below the deep part of the
submandibular glandsubmandibular gland
40. 40
Q 4Q 4
4-Mark following statements as true (T) or false (F):4-Mark following statements as true (T) or false (F):
A- Pleomorphic adenoma is the most common salivaryA- Pleomorphic adenoma is the most common salivary
gland tumorgland tumor
B- Mucoepidermoid carcinoma is the most commonB- Mucoepidermoid carcinoma is the most common
salivary gland tumorsalivary gland tumor
C- Parotid gland tumors are most commonly malignantC- Parotid gland tumors are most commonly malignant
D- Sublingual gland tumors are most commonlyD- Sublingual gland tumors are most commonly
malignantmalignant
E- Malignant Salivary gland tumors are treated byE- Malignant Salivary gland tumors are treated by
Surgical excision followed by postoperativeSurgical excision followed by postoperative
radiotherapyradiotherapy
