SEMINAR

PAROTID GLAND

Presented By:-Dr. Amrita Rastogi

M.D.S 1st Year

CONTENTS INTRODUCTION

PAROTID CAPSULE

SURFACE MARKING

EXTERNAL FEATURES

DEVELOPMENT

RELATIONS

STRUCTURE WITHIN THE PAROTID GLAND

PROCESSES

PAROTID DUCT

NERVE SUPPLY

LYMPHATIC DRAINAGE AND LYMPH NODES

HISTOLOGY

FUNCTIONS OF PAROTID GLAND

CLINICAL CONSIDERATIONS

ROLE OF PUBLIC HEALTH DENTIST

CONCLUSION

REFERENCES

INTRODUCTION [1] [2] [3] The salivary glands in mammals are a group of

compound exocrine glands, glands with ducts, that

produce saliva.

They are:

• Parotid gland

• Sub mandibular gland

• Sublingual gland

• Minor salivary glands

Parotid region contains the largest serous salivary

gland and the “queen of the face”, the facial nerve.

Parotid gland(Para=around; otic=ear) is the largest

major salivary gland.

Parotid gland contains vertically disposed blood

vessels and horizontally situated facial nerve and

various branches.

Paired parotid glands lying largely below the

external acoustic meatus between mandible and

sternocleidomastoid muscle and it also projects

forwards on the surface of masseter.

Sternomastoid

External acousticmeatus

Ramus of mandible

Occupies the deep hollow

behind the ramus of the

mandible.

Wedge-shaped when viewed

externally , with the base

above & the apex behind the

angle of the mandible.

On the surface of the masseter, smalldetached part lies between zygomatic archand parotid duct called as Accessory parotidgland or ‘socia parotidis’

• It is irregular, wedge shaped, and unilobular.

Parotid is 14-28 grams in weight and provides 60-

65% of total salivary volume.

• Dimensions:-

averaging 5.8 cm ( craniocaudal dimension),

3.4 cm (ventraldorsal dimension).

Parotid Capsule [1][3] The investing layer of the deep cervical fascia forms a

capsule for the gland. The fasica splits(between theangle of the mandible and the mastoid process) toenclose the gland.

Consists of :-

1) Superficial layer – It is thick and adherent to gland.

It extends from the masseter and

Sternocliedomastoid to the Zygoma,

2) Deep layer – It is thin and is attached to the styloid

process, the mandible and the tympanic plate.

A portion of the deep lamina extending between the

styloid process and the mandible, is thickened to form

the stylomandibular ligament which separates the parotid

glands from submandibular salivary gland.

The attachments of the Parotid fascia include :

Anterior – Mandible

Inferior – Stylomandibular ligament

Posterior –Styloid process

Surface Marking [5] The parotid gland is marked by joining the following

four points with each other.

a

b

c

d

a) The first point at theupper border of thehead of themandible.

b) The second pointjust above the centerof the massetermuscles.

c) The third pointposteroinferior toangle of mandible.

d) The fourth point isanterior border ofthe mastoid process.

External Features. [1] [2] [5]

The gland resembles a three sided pyramid. The apex

of the pyramid is directed downwards.

The gland has four surfaces:-

1) Superior (base of the pyramid)

2) Superficial

3) Anteromedial and

4) Posteromedial

The surfaces are separted by 3 borders:

a) Anterior b) Posterior and 3) Medial

Apex

Superior surface(Base)

Superficialsurface

Posterior border

Medial border

Anterior border

Development [5] [6] [7]

The parotid salivary glands appear early in the fourth week

of prenatal development and are the first major salivary

glands formed as an ectodermal furrow.

The epithelial buds of these glands are located on the inner

part of the cheek, near the labial commissures of the

primitive mouth.

These buds grow posteriorly toward the otic placodes of the

ears and branch to form solid cords with rounded terminal

ends near the developing facial nerve.

Later, at around 10 weeks of prenatal development,

these cords are canalized and form ducts, with the

largest becoming the parotid duct for the parotid

gland.

The rounded terminal ends of the cords form the

acini of the glands. Secretion by the parotid glands

via the parotid duct begins at about 18 weeks of

gestation. Again, the supporting connective tissue

of the gland develops from the surrounding

mesenchyme.

Relations [1] [2] [3]

The apex:

It overlaps the posterior belly of the diagastric and the

adjoining part of the carotid triangle. The cervical

branch of the facial nerve and the two divisions of the

retromandibular vein emerge through it.

The superior surface or base forms the upper end of

the gland :

It is small and concave. It is related to:

(a) The cartilagious part of the external acoustic

meatus.

(b) the posterior surface of the temporo mandibular

joint

(c) the superficial temporal vessels.

(d) the auriculotemporal nerve.

The superficial surface:

It is the largest of the four surfaces. It is covered with:

(a) Skin

(b) Superficial fascia containing the anteriorbranches of great auricular nerve, the perauricular orsuperficial parotid lymph nodes and the posteriorfibers of the platysma and risorius.

(c) the parotid fascia which is thick and adherent togland .

(d) a few deep parotid lymph nodes embedded in thegland.

The anteromedial surface:

It is grooved by posterior border of the ramus of the

mandible.

It is related to:

(a) The Masseter

(b) The lateral surface of temporomandibular joint.

(c) The posterior border of the ramus of the

mandible.

(d) The medial pterygoid.

(e) The emerging branches of the facial nerve.

The posteromedial surface:

It is moulded to the mastoid and styloid processes

and the structures attached to them.

They are related to:

(a)The mastoid process, with the sternocleidomastoid

and posterior belly of diagastric.

(b) The styloid process

The external carotid artery enters the gland through

this surface and internal carotid artery lies deep in the

styloid process.

Anterior border

Separates superficial surface from anteromedial

surface.

Structures which emerge at this border

Parotid Duct

Terminal Branches of facial nerve

Transverse facial vessels

Posterior Border

Separates superficial surface from

posteromedial surface

Overlaps sternocleiodomastoid.

Medial Border

Separates anteromedial surface from

posteromedial surface

Related to lateral wall of pharynx

Structures within the Parotid Gland [2] [3] Arteries

• The external carotid artery

• The maxillary artery

• Superficial temporal vessels

• The posterior auricular artery

Superficial temporal Artery

Maxillary Artery

Posterior auricular artery

External carotid

Veins

The retromandibular veins is formed within thegland by the union of the superficial temporal andmaxillary veins. In the lower part of the gland, thevein divides into anterior and posterior divisionswhich emerge at the apex of the gland.

Superficial temporal Vein

Maxillary Vein

Post auricular Vein

External jugular vein

Common Facial Vein

Retromandibular vein

Posterior division Anterior division

The facial nerve

It enters the gland through the upper part of itsposteriomedial surface, and divides into itsterminal beanches within the glands. Branchesappear on the surface at the anterior border.

Facial nerve

Temporal Branch

ZygomaticBranches

Upper buccal branch

Lower buccal branch

Marginal mandibular branch

Cervical Branch

Processes [7] The gland is an irregular

lobulated mass, sends

‘processes’ in various

directions. These include:

Glenoid process- that

extends upward behind the

temporo-mandibular joint,

in front of external auditory

meatus

Facial process- that

extends anteriorly

onto the masseter

muscle

Accessory process

(part)- small part of

facial process lying

along the parotid duct

Pterygoid process-that

extends forward from the

deeper part, lies between

the medial pterygoid

muscle & the ramus of

mandible

Carotid process-that lies

posterior to the external

carotid artery

Parotid Duct [5] [6] [8]

ductus parotideus; Stensen’s duct

It is thick walled and about 5cm long

and 5 mm in diameter

Carries saliva to the oral cavity.

Course :-

Forms by the union of smaller duct from the

gland and run forwards and slightly downward on

the masseter.

Relations

Superiorly:

(a) Accessory parotid gland.

(b) upper buccal branch of the facial nerve.

(c) the transverse facial vessels.

Inferiorly:

(a) The lower buccal branch of the facial nerve.

At the anterior border of the masseter, it turns

medially and pierces:

(a) the buccal pad of fat.

(b) the buccalpharyngeal fascia

(c) the buccinator

“Because of the oblique course of the duct through

the buccinator infaltion of the duct is prevented

during blowing.”

The duct runs forward for a short distance between

the buccinator and the oral mucosa.

The duct turns medially and opens into the

vestibule of the mouth (gingivo- buccal vestibule)

opposite the crown of the upper molar tooth.

Nerve Supply [1] [5] [9]

PARASYMPATHETIC(SECRETOMOTOR)

SUPPLY-derived from auriculo temporal nerve

Its stimulation produces watery secretion.

They reaches the gland through the

auriculotemporal nerve.

Pathway

Inferior salivatory nucleus

Preganglionicfibres

Glossophargealnerve

(ix cranial nerve)

tympanic branch

tympanic plexus

from

lesser petrosalnerve-

oticganglion

postganglionic fibres

auriculoemporalnerve

The parotid gland

To supply

SYMPTHETIC SUPPLY- they are vasomotor, and

are derived from the plexus around the external

carotid artery.

Stimulation produces thick sticky secretion.

SENSORY NERVES-comes from the

auriculotemporal nerve, but the parotid fascia is

innervated by the sensory fiberes of the great

auricular nerve.

Lympatic Drainage [9] [10] Lymph drains first to the parotid nodes and from there

to the upper deep cervical nodes.

Parotid lymph nodes The parotid lymph nodes lie partly in the superficial fascia and

partly deep to the deep fascia over the parotid gland.

They drain:-

(a) the temple

(b) the side of the scalp

(c) the lateral surface of the auricle

(d) the external acoustic meatus

(e) the middle ear

(f) the parotid gland

(g) the upper part of cheek

(h) parts of the eyelids

(i) orbit

Efferents from these nodes pass to the upper

groups of the deep cervical nodes.

Histology [4] [7] The salivary glands are a

group of compound exocrine

glands secreting saliva.

Salivary glands are composed

of serous and mucous acini, the

proportions of which

determine the type of salivary

secretion from each duct.

The Secretory Unit

– Acinus (serous, mucous, mixed)

– Myoepithelial cells

– Intercalated duct

– Striated duct

– Excretory duct

The parotid gland is a pure serous gland.

All acinar cells are similar in structure to the serous

cells. In the infants, however, a mucous secretory units

may be found.

The intercalated ducts of the parotid gland are long

and branching and numerous in striated ducts.

The connective tissue septa in the parotid contain

numerous fat cells, which increases in number with

age and leave an empty space in histological sections.

Functions of parotid glands [9]

[10] [11]

Protection of the oral cavity and oral enviroment: the

constant secretion of saliva prevents desiccation of oral

cavity.

Lubrication and cleansing oral cavity:

provides a washing action to flush away debris

and nonadherent bacteria and provide

lubrication for smooth and sliding movement.

Initiation of starch digestion: the action of

amylase on ingested carbohydrate to produce

glucose and maltose in the mouth.

Immunological: defensive substance in saliva are

the immunoglobulins. The perdominant salivary

immunoglobulin is IgA.

Parotid gland is the largest, provides 65% of the

total salivary volume. Normal outflow is 1-2L/day.

Clinical considerations [9] Diseases of parotid gland

1) Congenital

Aplasia or atresia- any one or group of salivary

glands may be absent, unilaterally or bilaterally.

Aplasia occurs for unkown reasons in conjunction

with other development defects such as hemifacial

microsomia, the LADD syndrome and mandibulo-

facial dysostosis.

Salivary loss leads to increased caries, burning

sensation, oral infections, taste aberrations and

difficulty with denture retention.

2) AcquiredInfective

MumpsBacterial sialadentitis

AutoimmuneSjögren's syndrome

InflammatorySialadenitis

NeurologicalFrey's syndrome

Neoplastic

Salivary gland neoplasm

Idiopathic

Sialolithiasis

Sialadenosis

Mumps [10]

Its a viral disease of the human species, caused by

the mumps virus Paramyxovirus.

Transmitted by direct contact, droplet spread, or

contaminated objects.

Painful swelling of the parotid gland.

Fever and headache are the

main symptoms of mumps,

together with malaise and

anorexia. Other symptoms of

mumps can include dry

mouth, sore face and/or ears

and occasionally in more

serious cases, loss of voice.

It was a common childhood diseases worldwide.

The disease is generally self-limiting, running its

course before receding, with no specific treatment

apart from controlling the symptoms with pain

medication.

Bacterial parotitis [11] [16]

It can be acute, chronic and recurrent.

The most common pathogens associated with

acute bacterial parotitis are Staphylococcus aureus

and anaerobic bacteria. The predominant

anaerobes include gram-negative bacilli.

It often occurs in the setting of debilitation,

dehydration, and poor oral hygiene, particularly

among elderly postoperative patient

Once an abscess has formed

surgical drainage is required. The

choice of antimicrobial depends

on the etiologic agent.

Maintenance of good oral hygiene,

adequate hydration, and early and

proper therapy of bacterial

infection of the oropharynx may

reduce the occurrence of

suppurative parotitis.

Sjögren's syndrome [7] [8]

Chronic inflammation of the salivary glands may

also be an autoimmune disease known as Sjögren's

syndrome

The disease most commonly appears in people

aged 40–60 years, but it may affect small children.

Women versus men is approximately 9:1.

The involved parotid gland is enlarged and tender at

times.

The cause is unknown. The syndrome is often

characterized by excessive dryness in the eyes, mouth,

nose, vagina, and skin

Frey’s Syndrome [12] [13]

Also known as gustatory sweating or auriculo-

temporal nerve syndrome.

Commonly occurs after parotid surgery or trauma.

It reflects the aberrant innervation of sweat glands

on the face by regrowing parasympathetic

secretomotor axons that would have previously

innervated the parotid gland.

It is characterized by

o Sweating

oWarmth

oRedness of the face

as a result of salivary

stimulation by the smell or

taste of food

There is no effective treatment, but various options

are:-

Injection of Botulinum Toxin A.

Surgical transection of the nerve fibers (only a

temporary treatment).

Application of an ointment containing an

anticholinergic drug such as scopolamine.

Sialadenitis (sialoadenitis) [11] [12]

It is the inflammation of asalivary gland. It may besubdivided into acute, chronicand recurrent forms.

Acute

• sialolithiasis

• decreased flow (dehydration,post-operative, drugs)

• poor oral hygiene

• exacerbation of low grade chronicsialoadenitis

Clinical features

• Painful swelling

• Reddened skin

• Edema of the cheek, Periorbital region and neck

• low grade fever

• malaise

• raised ESR, CRP, leucocytosis

• purulent exudate from duct punctum

Chronic

• Clinical Features unilateral

• mild pain / swelling

• common after meals

• duct orifice is reddened and flow decreases

• may or may not have visible/palpable stone.

• Recurrent painful swellings

Treatment

• In chronic recurrent sialadenitis or chronic

sclerosing sialadenitis, acute attacks are managed

with conservative therapies such as hydration,

analgesics (mainly NSAIDs), sialogogues to

stimulate salivary secretion, and regular, gentle

gland massage.

• If infection is present, appropriate cultures should

be obtained, followed by empirical antibiotic

therapy initially, for example

amoxicillin/clavulanate or clindamycin which

cover oral flora.

If there are attacks more than approximately 3

times per year or severe attacks, surgical excision

of the affected gland should be considered.

Salivary gland neoplasm [7] [10] [12] [13]

Salivary gland cancer is a cancer that forms in tissues

of a salivary gland.

Salivary gland cancer is rare, with 2% of head and neck

tumors forming in the salivary glands, the majority in

the parotid.

Salivary gland neoplasms are classified by the World

Health Organization as primary or secondary, benign

or malignant, and by tissue of origin. This system

defines five broad categories of salivary gland

neoplasms.

Malignant epithelial tumors (e.g. acinic cell carcinoma,

mucoepidermoid carcinoma and adenoid cystic carcinoma,

salivary duct carcinoma)

Benign epithelial tumors (e.g. pleomorphic adenoma,

myoepithelioma and Warthin tumour, sebaceous

lymphadenoma)

Soft tissue tumors (Hemangioma)

Hematolymphoid tumors (e.g. Hodgkin lymphoma)

Secondary tumors.

MUCOEPIDERMOID CARCINOMA PLEOMORPHIC ADENOMA

HEMANGIOMA

Signs and symptoms

Signs include fluid draining from the ear,

pain, numbness, weakness, trouble

swallowing, and a lump.

The most common symptom of major

salivary gland cancer is a painless lump in

the affected gland, sometimes accompanied

by paralysis of the facial nerve.

Causes

The chief risk factor is chewing tobacco, followed by

smoking. Other risk factors include older age,

radiation therapy treatment to head or neck, and

being exposed to certain carcinogenic substances at

work.

Treatment

• Surgery with or without radiation.

• Radiation therapy.

• Chemotherapy.

Sialolithiasis [11] [12]

Sialolithiasis (also termed salivary calculi, or

salivary stones), is a condition where a calcified

mass forms within a salivary gland, usually in the

duct of the submandibular gland (also termed

"Wharton's duct"). Less commonly the parotid

gland.

Signs and symptoms

Signs and symptoms are variable and depend largely

upon whether the obstruction of the duct is complete

or partial, and resultant pressure created within the

gland. The development of infection in the gland also

influences the signs and symptoms.

Pain, which is intermittent, and may suddenly get

worse before mealtimes, and then slowly get better

(partial obstruction).

Swelling of the gland, also usually intermittent, often

suddenly appearing or increasing before mealtimes,

and then slowly going down (partial obstruction).

Tenderness of the involved gland.

Palpable hard lump, if the stone is located near the

end of the duct. If the stone is near the submandibular

duct orifice, the lump may be felt under the tongue.

Lack of saliva coming from the duct (total

obstruction).

Erythema (redness) of the floor of the mouth

(infection).

Pus discharging from the duct (infection).

Cervical lymphadenitis (infection).

Treatment

Non-invasive: For small stones, hydration, moist heat

therapy, NSAIDs (nonsteroidal anti-inflammatory drugs)

Some stones may be massaged out by a specialist.

Shock wave therapy (Extracorporeal shock wave

lithotripsy).

Minimally invasive: Sialendoscopy

Surgical

Supporting treatment: To prevent infection while

the stone is lodged in the duct, antibiotics are

sometimes used.

Role of public health dentist [15]

During the treatment of oral cancer affecting

salivary glands leading to surgical removal of the

glands, leads to decreased or no saliva secretion.

This increases the incidence of dental caries.

Patient under the high dose of radiation therapy

reduce the quality and quantity of normal saliva,

causing radiation caries.

Fluoride application

Maintaining the periodontal health.

Educating about proper nutrition and good oralhygiene.

Dentures reconstruction in case of altered oral tissue.

Educating and motivating people about tobaccocessation.

Conclusion The parotid glands are a pair of mainly serous salivary

glands located inferior and anterior to the external acoustic

meatus, draining their secretions into the vestibule of oral

cavity through the Stensen duct or parotid duct.

The parotid gland also secretes salivary alpha-amylase

(sAA), which is the first step in the decomposition of

starches during mastication.

Parotid gland is the largest, it provides 65% of the total

salivary volume. The serous cell predominates in the

parotid, making the gland secrete a mainly serous

secretory product.

Apart from viral infection, other infections, such as

bacterial, can cause parotitis (acute suppurative

parotitis or chronic parotiti). These infections may

cause blockage of the duct by salivary duct calculi or

external compression.

About 80% of tumors of the parotid gland are benign.

Surgical treatment of parotid gland tumors is

sometimes difficult because of the anatomical

relations of the facial nerve parotid lodge, as well as

the increased potential for postoperative relapse. Thus,

detection of early stages of a parotid tumor is

extremely important.

References 1) Guyton and Hall ;Textbook of medical physiology

9th edition pg no. 223-254.

2) Tortora-Derrickson; Principal of anatomy and

physiology,12th edition pg no. 112-114.

3) Chaudhuri; Concise medical physiology , 2nd

edition. Pg no. 34-36.

4) A.K.Jain Human physiology ,1st edition. Pg no. 454-

456.

5) K.Sembulingum,P.Sembulingum;Essentials of

medical physiology,4th edition pg no.555-557.

6) Burket’s ;Oral medicine ,11th edition pg. no. 211-213.

7) Principal of anatomy and physiology- tortora-

derrickson ,12th edition.

8) Richard Tencate ;ORAL HISTOLOGY-5th edition pg.

no. 339-342.

9) Robert M Bradley ;ESSENTIALS OF ORAL

PHYSIOLOGY pg. no. 221-223

10) G.Neil Jenkins ;The physiology and biochemistry of

the mouth, 4th edition pg.no. 11-13

11) Christopher L B Lavelle ;APPLIED ORAL

PHYSIOLOGY-2nd edition.

12) Greenberg& Glick ;BURKETS ORAL MEDICINE-

10th edition pg. no. 41-43

13) Shafer,Hine & Levy ;Textbook of Oral Pathology

6th edition pg. no. 134-144.

14) Saliva:its secretion,composition&functions.-

British Dental Journal 1992; 172:305

15) The effect of saliva on dental caries George K.

Stookey, MSD, PhD

10.14219/jada.archive.2008.0347 2008;139(suppl

2):11S-17SJADA

16) J Craniofac Surg. 2003 Jan;14(1):37-40.

Acute bacterial suppurative parotitis:

microbiology and management.