salivary gland,submandubular and lingual gland

1. Anatomy and physiology of
Salivary Glands
Dr Sandeep Shrestha
2nd year Resident
ENT
NMCTH

2. Embryology
• All major salivary glands- ectoderm
• Some minor- ectoderm and endoderm
• Parotid gland(6th wk)----submandibular(6th
wk)----sublingual(8th wks)
• Parotid - first to develop but - last become to
encapsulated, after the lymphatics develop.
• Results in entrapment of the lymphatics deep
to the capsule in the parenchyma of the gland.

3. Applied anatomy
• Salivary epithelial cells - included within these
lymph nodes and this may be important in the
development of Warthin’s tumours and
lymphoepithelial cysts within the parotid
gland.

4. • The major glands lie distant to the oral
mucosa, and are connected to the mucosa by
excretory ducts.
• The minor glands lie within the mucosa or
submucosa of the oral cavity and oropharynx
and either open directly onto the surface of
the mucosa or are connected to it via short
excretory ducts.

5. Microscopic anatomy
• Salivary glands are made up of secretory acini
and ducts.

6. The acinus
Three types of acinus
• Serous (protein-secreting) – spherical cells rich
in zymogen(small granules) granules
• Mucous (mucin-secreting) – tubular shaped
cells; mucin granules(larger granules producing
mucoproteins)
• Mixed – varying proportions of serous and
mucous acinar cells.

7. • Within the acinus, the acinar cells and the cells of
the proximal ductal system (intercalated duct) are
enveloped by pseudopodia of surrounding
myoepithelial cells.
• Contractile properties and create the peristalsis
action which moves saliva away from the acinus,
distally along the salivary duct system.
• The lumen of the acinus communicates directly
with the lumen of the duct.
• The ductal system, from proximal to distal,
comprises the intercalated duct, striated duct and
excretory duct.

8. low cuboidal
epithelial
secrete
bicarbonate
and absorb
chloride
short and
poorly
developed in
mucinous
salivary glands
The intercalated duct

9. simple cuboidal cells
absorb sodium and
secrete potassium
producing hypotonic fluid
well developed in serous
glands
The striated and excretory duct
simple cuboidal epithelium
proximally and striated
cuboidal or pseudostratified
columnar epithelium distally

10. • The salivary gland stroma is rich in
lymphocytes and plasma cells, which are
responsible for the production of IgA, which is
secreted into the salivary duct system to be
excreted in the saliva.

11. Types of salivary glands
• Major salivary glands(paired)
1.Parotid gland
2.Submandibular gland
3.Sublingual gland
• Minor salivary glands

12. Parotid gland
• Largest salivary gland
• Mainly serous
• Inverted pyramid
• Average weight-25gm
• Irregular wedge shaped
• Extend
– Sup : zygomatic arch
– Inferior : upper part of neck
– Ant : masseter muscle
– Post : external auditory
canal and onto the mastoid
process

13. • Gland has 4 surfaces
– Superficial / lateral
– Superior
– Anteromedial
– Posteromedial
• 3 borders
– Anterior
– Posterior
– Medial

14. Superficial surface
• largest
• Concave
• Covered by the parotid
fascia, skin and the
posterior border of
platysma.
• Some branches of the
great auricular nerve lie
superficial to the gland
tissue and superficial
lymph nodes lie on or
deep to the fascia as well
as within the gland

15. Anteromedial surface
• Ascending ramus of the
mandible
• Medial pterygoid muscle
• Masseter
• Lateral surface of the
tempormandibular joint
• The facial nerve and
parotid duct emerge from
this surface and run
forwards deep to the
anterior border
• The maxillary artery leaves
the anteromedial surface

16. Posteromedial surface
• lies on the mastoid process, the
posterior belly of the digastric and
the sternocleidomastoid muscles.
• Medially it overlies the styloid
process with its attached muscles
(styloglossus, stylohyoid and
stylopharyngeus), which separate
the gland from the internal carotid
artery and internal jugular vein
within the carotid sheath.
• This surface is indented by the
external carotid artery prior to its
entering the gland.
• The facial nerve trunk enters the
gland high on the posteromedial
surface between the mastoid and
styloid processes.

17. Superior surface
• Forms the upper end of
the gland
• Small and concave
• Cartilagenous part of the
external acoustic meatus
• Posterior surface of the
TMJ
• Superficial temporal
vessel
• Auriculotemporal nerve

18. Anterior border
• Seperates superficial
surface from the
anteromedial surface
• Extend from anterior part
of the superior surface to
the apex
• Parotid duct
• Terminal branch of facial
nerve
• Transverse facial vessels
• Accessory parotid gland
lies on the parotid duct

19. Posterior border
• Seperates the
superficial surface from
the posteromedial
surface.
• Overlies the SCM

20. Medial border
• Seperates the
anteromedial surface
from the posteromedial
surface
• Related to the lateral
wall of the pharynx

21. Structure within the parotid gland
Arteries :
• ECA enters the gland
through its posteromedial
surface
• Divides into the maxillary
and superficial temporal
artery within the gland
• The maxillary artery leaves
the anteromedial surface
• Superficial temporal artery
continues superiorly to exit
the gland from its superior
surface

22. Veins
• Superficial to the maxillary and
superficial temporal arteries lie
the corresponding veins - unite
- form the retromandibular
vein.
• The retromandibular vein
emerges from the lower pole of
the gland and divides into two
branches.
• The anterior branch joins the
facial vein before entering the
internal jugular vein.
• The posterior branch joins the
posterior auricular vein to form
the external jugular vein.
• The division may occur within
the gland and two branches
emerge from the lower pole

23. Facial nerve
• Exits from cranial cavity
through stylomastoid
foramen
• Enters the gland through
upper part of its
posteromedial surface.
• Divides into two main
temporal and cervical
divisions.
• These pass forwards
anteriorly dividing further
before emerging from the
anteromedial surface of the
gland.

24. • The nerve divides the
gland into
superficial(80%) and deep
lobes(20%).
• The nerve lies superficial
to the retromandibular
vein, which is in turn
superficial to the external
carotid artery.
Applied anatomy :The vein
can be a useful
radiological landmark for
the nerve.

25. It exits the skull base via
stylomastoid foramen it
gives off 3 motor
branches upon exiting
the foramen to styloid
muscle,post. Auricular
muscle,post.belly of
digastric .

26. • After exiting foramen
facial nerve turns
laterally to enter post.
Margin of gland
• Nerve branches at pes
anserinus(goose foot)
approximately 1.3cm
from stylomastoid
foramen
• Then gives 2 branches
– temporofacial(upper)
– cervicofacial(lower)

27. • Followed by 5 terminal
branches
1.Temporal
2.Zygomatic
3.Buccal
4.Marginal mandibular
5.Cervical

28. Katz and catalano classification of
facial branches
. Type 1- classical type(25%), subtypes –division and reunion
within the zygomatic and mandibular branches
. Type2---(14%), buccal branches subdivided and fuse with
zygomatic branch
. Type 3- (44%), major communication from buccal branch to
others
. Type 4 – (14%), two or more buccal branches with several
anastomosis with each other and other branches
. Type 5- (3%), facial nerve leave the skull as more than one trunk

30. Surgical landmarks
1.Tragal pointer
2.Tympanomastoid suture
3.Post. Belly of digastric
ms
4.Styloid process

31. Parotid lymph node
• Lies partly in the superficial fascia and partly
deep to the deep fascia over the parotid
gland.
• Drain into temple, side of the scalp, lateral
surface of the auricle, EAC, ME, Parotid gland,
upper part of the cheek, parts of the eyelids
and orbit.
• Efferents from this node pass to the upper
deep cervical nodes.

32. • Isthmus of parotid
gland runs between
mandibular ramus and
post. Belly of digastric
to connect
retromandibular
portion of remainder of
gland

33. • This portion of gland lies
in prestyloid
compartment of
parapharyngeal space.
Applied anatomy
• Thus deep parotid
tumour push-tonsillar
fossa
• Parotid tumour-that
involve parapharyngeal
space- dumbbell tumour

34. Patey’s faciovenous plane
Gland composed of a large superficial and small
deep part, connected by an isthmus around which
facial nerve divides.
Clinical significance:
• Facial nerve must be traced from behind forwards
as it emerges from the stylomastoid foramen and
enters the parotid gland.
• Nerve is surrounded by a leash of veins called
neuro-venous plexus of patey which must be
followed with fine dissection, to surgically divide
the isthmus.

35. Stenson’s duct
• lined by low cuboidal
epithelium surrounded
by a smooth muscle and
fibrous tissue wall.
• It originates within the
gland, enveloped by the
deep lobe of the parotid
• Only small ductules
connect the superficial
lobe with the duct.

36. • Length – approx 5 cm
• Wide – 3mm
• Diameter- internal calibre of
about 0.6mm
• It emerges from the
anterior border of the
parotid gland
• Travels across the masseter
muscle
• Having received the duct
from the accessory gland it
turns medially at the
anterior border of the
masseter.

37. • It pierces buccinator and runs
obliquely between buccinator
and the oral mucosa before
entering the oral cavity at the
parotid papilla opposite the
second upper molar tooth.
• The facial nerve and its
branches are always observed
lateral to the parotid duct.
• The surface marking is the
middle of a line between the
intertragal notch of the
auricle and the midpoint of
the philtrum.

38. Accessory parotid gland
• Pars accesoria or socia
parotidis
• Separate part of the gland
usually lying on the
masseter muscle between
the parotid duct below
and the zygomatic arch
above.
• Noted in 20% of people
• Typically lies cranial to
stensen’s duct

39. Parotid fascia
• Derived from the investing
layer of the deep cervical
fascia.
• Continuous anteriorly with
the fascia covering the
masseter as the
parotidomasseteric and
extends up to the zygomatic
arch.
• The deep part extends to the
base of the skull and is
thickened between the
styloid process and the angle
of the mandible forming the
stylomandibular ligament.

40. • The fascia is largely tough and inelastic but
thins anteriorly.
• Relatively thin fascia over the apex of the
gland .
• With in the capsule are superficial parotid
lymph nodes and greater auricular nerve.

41. Applied anatomy
• Apex - lead to the spread of sepsis into the
parapharyngeal space.
• Inflammatory oedema pus and rapidly growing
tumours contained within the capsule will cause
it to stretch and become painful.
• Most parotid tumours arise from the superficial
lobe and expand towards the superficial surface
• Deep lobe tumours are limited by the
stylomandibular ligament and expand into the
parapharyngeal space.

42. Greater auricular nerve
• 1st nerve to encounter in
surgery lat. to parotid fascia
and deep platysma.
• Passes deep to superficial
around the post. Border of
SCM then traverse sup. and
post. to ext. jugular vein
• Nerve arise from cervical
plexus, provides sensation to
post. Pinna and lobule
• Erb’s point- 1cm above
where GAN wind around
SCM on its way to supply
parotid fascia

43. Auriculotemporal nerve
• Branch of mandibular
nerve
• Runs ant to EAC
paralleling the sup.
Temporal art. and vein
• Carries parasympathetic
postganglionic fibers to
parotid gland

44. • It provides sensory innervation to parotid
capsule, skin of auricle and temporal region
Applied anatomy :
• Referred pain from parotitis can involve EAC,
TMJ and temples
• Injury of Auriculotemporal nerve can lead to
Frey’s syndrome.

45. Blood supply
• Branches of the
external carotid artery
supply the gland.
• Venous drainage is via
the retromandibular
vein into the external
and internal jugular
veins.

46. Lymphatic drainage
• Parotid lymphatics drain
into upper deep cervical
lymph node.

47. Nerve supply
parasympathetic
Inferior salivatory nucleus
CN IX
Tympanic branch
Tympanic plexus
Lesser superficial petrosal nerve
Relay in Otic ganglion
Auriculotemporal nerve
Salivary gland

48. sympathetic
• Via the plexus on the
external carotid and
middle meningeal
arteries from the
superior cervical
ganglion.

49. Clinical implication
• Acute parotitis: painful due to unyielding nature
of parotid fascia.
• A Parotid abscess may be caused by spread of
infection from the opening of parotid duct in the
oral cavity.
• Does not show fluctuation due to unyielding
nature of parotid capsule.
• Parotid abscess is best drained by horizontal
incision known as hilton’s method below angle of
mandible.

51. Submandibular gland
• Second largest
• Size of walnut
• Lies in the
submandibular triangle
• Weighs : 7–16 g
• Roughly j shaped
divided by mylohyoid
1.Superficial (larger)
2.Deep (smaller)

52. Superficial part
• Fills the digastric triangle
• Extend upwards deep to the mandible up to
the mylohyoid line
• 3 surfaces
– Inferior
– Lateral
– Medial
• Covered by skin, platysma and a fibrous
capsule, derived from the deep cervical fascia.

53. • The capsule runs from the
greater cornu of the hyoid
bone and splits to enclose
the gland before blending
with the periostium of the
mandible along the
mylohyoid line medially,
and the lower border of the
body of the mandible
laterally.
• The fascia is crossed by the
facial vein, the cervical
branch of the facial nerve
and the marginal
mandibular branch of the
facial nerve.

54. Lateral surface
• lies adjacent to the body of
the mandible in the
mandibular fossa and the
origin of the medial
pterygoid.
• The facial artery enters or
deeply grooves the gland
posteriorly, after emerging
from deep to the superior
margin of the posterior belly
of the digastric.
• It initially lies deep to the
gland before turning
anterolaterally to emerge
between the gland and the
lower border of the mandible.

55. Medial surface
• Lies on the surface of
mylohyoid anteriorly,
with the nerve to
mylohyoid and
submental vessels.
• Posteriorly the gland
overlies hyoglossus, the
lingual nerve with its
submandibular ganglion,
hypoglossal nerve,
stylohyoid and posterior
belly of the digastric.

56. Inferior surface
Overlaps stylohyoid and the posterior belly of
the digastric.

57. Deep part
• Small part
• Gland lies between mylohoid and hyoglossus.
• Posteriorly continous with the supericial part
around the posterior border of the mylohyoid.
• Anteriorly : extend up to the posterior end of the
sublingual gland
Relation
Laterally : mylohyoid
Medially : hyoglossus
Above : lingual nerve with submandibular ganglion
Below : hypoglossal nerve

58. Submandibular duct(wharton’s duct)
• Approximately 5 cm long
• Mean duct diameter : 0.5 -
1.5 mm
• It is formed by the
coalescence of numerous
ducts within the superficial
part of the gland
• Emerging from the medial
surface of this part of the
gland
• Traversing the deep part
before running anteriorly
along the floor of the mouth
between mylohyoid and
hyoglossus.

59. • It emerges on the summit of the sublingual
papilla adjacent to the lingual frenulum after
passing between the sublingual gland and
genioglossus.
• While running forwards on hyoglossus, it lies
between the hypoglossal and lingual nerves.
• The lingual nerve crosses the duct laterally at the
anterior edge of hyoglossus before branches of
the nerve emerge on the medial surface of the
duct.

60. Nerve supply
• The sympathetic innervation : superior cervical
ganglion via the lingual artery.
• Presynaptic parasympathetic innervation : via
the lingual nerve, a branch of the mandibular
division of the Vth cranial nerve to the
submandibular ganglion.
• Innervation is initially from the superior
salivatory nucleus in the pons passing through
the nervus intermedius and carried by the
chorda tympani nerve.

61. Superior salivatory nucleus
Nervus Intermedius
Facial nerve
Chorda tympani
Lingual nerve,br of V3
Submandibular ganglion
Post ganlionic fibres
Submandibular gland

62. Arterial supply
• Submental branch of
facial artery(br. Of ext.
carotid art) forms
groove in deep part of
the gland then curve up
around the inf. Margin
of mandible to supply
the face.

63. Venous drainage
• Anterior facial vein
deep to marginal
mandibular vein
Lymphatic drainage
• Into the deep cervical
group, particularly the
jugulo- omohyoid
nodes.

64. Applied anatomy
• 80-90% of sialolithiasis
in submandibular gland
• 85% in wharton’s duct
• Complete ductal
obstruction result in
atrophy of gland
• Partial obstruction
glandular mucocele

65. Applied anatomy
• An important anatomical relationship is that the
marginal mandibular nerve passes lateral to the
vein and, therefore, dissecting deep to the vein,
can be used to preserve or identify the nerve.
• Perivascular L.N near the facial art are often
involved with cancer originating in
submandibular gland and nodes should be
removed with submandibular resection

66. Sublingual gland
• Smallest of major salivary
gland
• Wt- approx 4 gm
• Almond shaped
• Lies deep to floor of mouth
mucosa between mylohyoid
ms and body of mandible
close to symphysis
(sublingual fossa)
• Whartons duct and lingual
nerve pass between
sublingual gland and
genioglossus ms

68. • Has no true capsule
• Lack single dominant
duct- drained by approx.
10 small ducts(duct of
rivinus) which open along
the sublingual gland on
the floor of mouth
• Occassioonally several
more ant duct may join to
form common
duct(bartholin duct)
which typically opens into
whartons duct

69. Innervation
• Sympathetic-cervical chain via facial artery
• Parasympathetic-submandibular ganglion

70. Arterial supply
• Sublingual branch of
lingual artery
• Submental branch of
facial artery
Venous drainage-reflects
artery supply
Lymphatic-submandibular
nodes

71. Physiology of salivary glands

72. Introduction
• Salivary glands produce saliva, which plays an
important role in the maintenance of oral health.
• The largest portion of total saliva volume is
produced by three paired major salivary glands:
the parotid, the submandibular and the
sublingual salivary glands.
• In addition, there are 600–1000 minor salivary
glands present in the mucosal lining of the oral
cavity and oropharynx that also contribute to
total saliva production.

73. Types of salivary gland secretion
Gland Acinar type Viscocity %of whole
unstimulated saliva
Parotid Serous Watery 26
Submandibular Mixed semiviscous 69
Sublingual Mucous Viscous 5
Minors Mucous Viscous trace

74. Composition of saliva
• 99.5%-water
• Proteins
• Glycoproteins
• Electrolytes
• High in k+(7*plasma) HCO3(3*plasma), Ca, P,
Cl, thiocynate and urea
• Low in Na+(1/10*plasma)
• pH of 5.6–7.4

77. Phases of salivary secretion
• Active process in 2 phase
1.Primary phase-occur in acinar cells (product
similar in composition and osmolality to
plasma)
• 2.Ductal secretion- result in hypotonic salivary
fluid with decreased sodium and increased
potassium concentrations.

79. THE AUTONOMIC NERVOUS SYSTEM
AND SALIVARY SECRETION
• Parasympathetic principal impetus for salivary
secretion
• Act through neurotransmitter acetylcholine
• Also causes 1. exocytosis
2. protein secretion
3. myoepithelial contraction
4.vasodilation

80. • Sympathetic- weak mobilizer of salivary fluid
• Act through nor epinephrine
• Also causes- 1. high level of protein secretion
2. myoepithelial contraction
3. maintenance of vasculature

81. In general
• Parasympathetic activity lead to output of
saliva that has large volume and low protein
• Sympathetic activity lead to secretion of low
volume of saliva with high protein content

82. MECHANISMS OF
SALIVARY SECRETION

84. MECHANISMS OF ION TRANSPORT
IN SALIVARY ACINI
• As in all secretory epithelia, fluid transport in salivary
gland cells is thought to be driven osmotically by
transepithelial concentration gradients.
• Three mechanisms that act concurrently resulting in the
production of primary salivary fluid secretion.
• The first mechanism depends on the combined action of
four membrane transport systems
– Na+ -Cl− co-transporter that is located in the basolateral
membrane of the acinar cells
– Basolateral Ca++-activated K+ channel
– An apical conductive pathway for Cl−, which is presumably a
Ca++ -activated Cl− channel
– Basal Na+ / K+ ATPase

85. MECHANISMS OF ION TRANSPORT
IN SALIVARY ACINI
Na
K2
CL

86. Factors affecting salivary flow
• Age – postmenopausal women
• Drugs – TCA, neuroleptics, anti parkinsonian
agents, antiemetics, antihistamine
• Disease- autoimmune sialadenitis, HIV,
radiation damage, graft versus host disease,
sarcoidosis, iron overload, amyloidosis, and
type v hyperlipoproteinemia
• Anxiety and depression induced xerostomia

88. Constituents
Inorganic
constituent(mEq/L)
Parotid gland Submanibular gland
K+ 20 17
Na+ 23 21
Cl- 23 20
HCO3- 20 18
Ca++ 2 3.6
Mg++ 0.2 0.3
HPO4-- 6 4.5

89. Organic
constituents(mg/dl)
Parotid Submandibular
Urea 15 7
Ammonia 0.3 0.2
Uric acid 3 2
Glucose <1 <1
Cholesterol <1 -
Fatty acids 1 -
Total lipids 2-6 2-6
Aminoacids 1.5 -
Protein 250 150

90. Salivary flow
• The average volume of saliva secreted from the major
salivary gland in a 24-hour period is 1–1.5 litres.
• Most saliva is secreted during mastication.
• The basal salivary flow rate is 0.001–0.2 ml / minute / gland
• Stimulated salivary flow rate increases to 0.18–1.7 ml /
minute / gland
• In contrast, the salivary flow from the minor salivary glands
is independent of stimulation and constitutes 7–8% of total
salivary output.
• The saliva produced by minor salivary glands is rich in
mucin and is primarily responsible for maintaining oral
mucosal lubrication.

91. In an unstimulated state the contribution of measured
Salivary gland is:
• Submandibular gland: 69%
• Parotid gland: 26%
• Sublingual gland: 5%
In a stimulated phase the relative contributions of major
salivary glands are:
• Parotid gland: 69%
• Submandibular gland: 26%
• Sublingual gland: 5%

92. Collection of saliva
• The collection of saliva is performed under three
circumstances:
• Unstimulated flow of total saliva
• Stimulated flow of total saliva
• Stimulated or unstimulated flow of an individual
gland.

93. • Systemic or local sialagogues may be used to stimulate
flow.
• Systemic salivary sialagogue is pilocarpine, a
parasympathomimetic, although this is rarely used outside
research.
• A commonly used protocol involves the dropwise
application of 5% citric acid solution on the dorsum of the
tongue.
• As for collecting saliva, a variety of methods are used.
– Spitting
– Drainage
– Suction
– cotton wool rolls.

94. Collection of parotid gland saliva
• Collected by cannulating parotid duct with
polythene catheter or suction cup.
• Suction cup(Carlson-Crittenden cup/Lashley’s
cup)

95. Collection of submandibular and
sublingual gland saliva
• Saliva produced by the submandibular and sublingual
glands is typically collected using a syringe.
• Individual gland production is technically impossible
due to the close proximity of duct orifices in the
anterior floor of mouth or more pertinently by the
numerous potential communicating channels between
the duct systems of all four glands.

96. Radioisotope salivary function test
• 99mTc pertechnicate is used for study of
salivary gland function.
• With scintigraphy objective measure of its
uptake, concentration and excretion can be
made
• Both parotid and submandibular gland can be
studied at same time.

97. Change in condition of inorganic ion
condition Change in concentration of inorganic ion
sialadenitis Raised Na+, K+ Ca++&P+ level
Radiation damage Raised Na+, Ca++, Mg++, Cl-
Sjogren’s syndrome Raised Na+, Cl- & P+ in parotid gland saliva
Cystic fibrosis Raised Na+, Ca++&P+ levels
hypertension Decreased Na+ level
Aldosteronism Decreased Na+ , but raised K+ level
Alcoholic cirrhosis Raised K+
Hyperparathyroidism Raised Ca++ levels
Diabetes mellitus Raised Ca++ levels
Chronic pancreatitis Depressed HCo3 level
Psychiatric illness Raised Na+ level

98. Conditions affecting composition of
saliva
Condition Effect on composition of saliva
Sjogren’s syndrome Raised total protein and beta 2
microglobulin in parotid gland saliva
Cystic fibrosis Raised protein, amylase, lysozyme in
submandibular gland saliva and
glycoprotein in parotid gland saliva
Cirrhosis Raised protein & amylase in parotid gland
saliva
Hyperparathyroidism Raised total protein
Diabets mellitus Raised total protein , IgA , IgG, IgM &
raised glucose level
Sarcoidosis Depressed amylase and lysozyme level

99. Salivary assays in diagnosis
Malignancy screening P53 tumor suppressor protein and
increased level of peptide defensin 1 on
oral sq cell ca
Raised level of c-erB2 and ca Ag 15-3 in
breast ca
Hormone monitoring Testorone , estradiol(unproven)
Drug monitoring Caffeine, carbamazepine, cisplatin,
cyclosporine,diazepam, digoxine,
ethosuximide, lithium, cocaine ,
marijuana, nicotine, opoids, phencyclidien
etc

100. Thank you