PAROTID GLANDS

PRESENTED BY-

PARTHSARTHI GAUTAM

1ST YEAR M.D.S

DEPT. OF ORAL MEDICINE & RADIOLOGY

NARSINHBHAI PATEL DENTAL COLLEGE & HOSPITAL

content

introduction

Definition

Development

Anatomy

Parts & relations

Blood supply, nerve supply

Histology

Applied anatomy

Differential diagnosis

ReferencesNo. of slides- 41

The salivary glands in mammals are exocrine glands, glands with ducts, that produce saliva. They also secrete amylase, an enzyme that breaks down starch into maltose

Parotid gland

Submandibular gland

Sublingual gland

Minor salivary glands

PAROTID GLANDS

PAIRED PAROTID GLANDS ARE LARGEST OF SALIVARY GLANDS LYING LARGELY BELOW THE EXTERNAL ACOUSTIC MEATUS BETWEEN MANDIBLE AND STERNOCLEIDOMASTOID MUSCLE AND IT ALSO PROJECTS FORWARDS ON THE SURFACE OF MASSETER

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

Gross anatomy.

Weight– 25g. Shape – Inverted pyramid.

In 30% cases upper and lower poles are rounded.

Surface – Irregular, lobulated.

Site – in the parotid region bounded by

anterior – posterior border of body of ramus.

posterior – mastoid process and

sternocleidomastoid muscle.

inferior – digastric and stylohyoid.

superior – external acoustic meatus and TMJ.

Medially – Styloid process. Coverings –

- Inner true capsule formed by condensation of fibrous stroma of the gland.

- Outer false capsule[Parotid Sheath] formed by splitting of investing layer of deep cervical fascia.

DEVELOPMENT

Each parotid is developed during 4th week in intrauterine life from angle of primary oral fissure as an ectodermal furrow.

The groove is converted into tube which forms duct and opens into angle of primitive mouth.

From the lateral end of duct cords of ectodermal cells project into surrounding mesoderm and subsequently canalise.

The salivary glands arise as buds from The epithelial lining of the mouth; theparotid appears during the fourth weekIn the angle between the maxillaryprocess and the mandibular arch

Opening of parotid duct indicates position of angle of primitive mouth

StomodeumBuccopharyngeal membrane

ProctodeumCloacalmembrane

Fore-gut

Mid-gut

Hind-gut

Pre-Laryngeal(Cephalic part)

Post-Laryngeal(Caudal part)

GUT TUBE

Pharynx and

Part of definitiveMouth cavitySkin ectoderm

Parotid gland4th week of IUL

Ectodermal furrow

With the growth of maxillary and mandibular process the duct opening is shifted to vestibule opposite the upper 2nd molar tooth.

Ectodermal origin is proved by the presence of myoepithelial cells.

During development the gland lies in between the branches of facial nerve, as development progresses it envelopes the branches.

The parotid development is usually associated with the transient ectodermal outgrowth known as Chievitz’s organ. This structure may contribute to the parotid gland but usually disappears.

APEX BASEUPPER SURFACE

SURFACES BORDERS

SUPERFICIAL/LATERAL

ANTERO- MEDIAL POSTERO-MEDIAL

ANTERIOR POSTERIOR MEDIAL

Parts

Parotid – 3 sided pyramid

Apex

Superior surface (Base)

Superficialsurface

Antero

-medial

surfa

ce

Postero-medial

surface

Anterior border

Posterior border

Medial border

Parts & relation

BASE – UPPER PART OF THE GLAND

RELATION

EXTERNAL ACOUSTIC MEATUS, TEMPOROMANDIBULAR JOINT

,SUPERFICIAL TEMPORAL VESSELS, AURICULOTEMPORAL NERVE,

TEMPORAL BRANCH OF FACIAL NERVE

APEX DIRECTED DOWNWARDS –

SMALL PART LIES IN CAROTID TRIANGLE

RELATIONANTERIOR & POSTERIOR DIVISION OF RETROMANDIBULAR VEIN,CERVICAL

BRANCH OF FACIAL NERVE

Superficial (lateral)

Skin & superficial fascia

Great auricular nerve

Parotid lymph nodes

Anteromedial: 1.Stylomandibular ligament

2.Medial pterygoid

3.Posterior border of the ramus of mandible

4.Massater

5.Terminal branches of the facial nerve

1

2

3

4

5

Posteromedial: Carotid sheath with its

contents

Styloid process & attached muscles

Facial nerve

Posterior belly of digastric muscle

Mastoid process

Sternocleidomastoid

1

2

3

4

5

6

ANTERIOR BORDER

ZYGOMATIC BRANCH OF FACIAL NERVE, TRANSVERSE FACIAL VESSELS,

UPPER BUCCAL BRANCH OF FACIAL NERVE, ACCESSORY PAROTID DUCT,

PAROTID DUCT, LOWER BUCCAL BRANCH OF FACIAL

NERVE, MARGINAL MANDIBULAR BRANCH OF FACIAL NERVE

POSTERIOR BORDER

STERNOCLEIDOMASTOID MUSCLE, POSTERIOR AURICULAR VESSELS

MEDIAL BORDER

PHARYNX

Processes

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

The gland is an irregular lobulated mass, sends ‘processes’ in various directions. These include:

Structures Coursing Within the Parotid Gland 1.Auriculotemporal nerve

2.External carotid artery

3.Retromandibular vein

4.Facial nerve

A few lymph nodes are scattered in the substance of the gland

Deep

Superficial

1

2

34

Lobes

The facial nerve courses horizontally through the gland and divides it into: Superficial lobe

Deep lobe

Superficial lobe

Deep lobe

Facial nerve

PAROTID DUCT

KNOWN AS STENSEN’S DUCT LENGTH – 5CM

CARRIES SALIVA TO THE ORAL CAVITY

COURSE FORMS BY THE UNION OF SMALLER DUCT FROM THE

GLAND, RUNS ON THE MASSETER MUSCLE & BENDS AT THE ANTERIOR BORDER OF THE MUSCLE & PIERCES

SUCCESSIVELY BUCCAL PAD OF FAT, BUCCOPHARYNGEAL FASCIA & BUCCINATOR MUSCLE. AGAIN BENDS & FINALLY

EMERGES INSIDE THE ORAL CAVITY AT THE CROWN OF THE UPPER 2ND MOLAR TOOTH

Arterial supply: External carotid artery & its

terminal branches

Venous drainage: Into the retro-mandibular vein

Lymph Drainage: Into the parotid & then into the

deep cervical lymph nodes

Nerve Supply

Sensory :

Auriculotemporal n. Autonomic:

• Sympathetic through plexus around the arteries ( around ECA)

• Parasympthetic through otic ganglion (CN9-tympanic n.- lesser petrosal n.- otic ganglion-auriculotemporal n.)

HistologySalivary glands are composed of serous and mucous acini, the proportions of which determine the type of salivary secretion from each Duct

Parotid is mainly serous

Sublingual is mainly mucous

Submandibular is mixed

The Secretory Unit– Acinus (serous,

mucous, mixed)– Myoepithelial cells– Intercalated duct– Striated duct– Excretory duct

Striated & Intercalated ducts well developed in serous, NOT mucous glands

Striated duct: HCO3 into, Cl from lumen

Intercalated duct: K into lumen, Na from lumen, producing hypotonic fluid

Excretory ducts do NOT modify saliva

Minor salivary glands tend to be under local control, whereas major glands are parasympathetically controlled

Saliva is hypotonic, with low concentrations of NaCl, high KHCO3

Antibodies (IgA), amylase, lysozyme, Lactoperoxidase

Submandibular saliva has relatively high Ca

Functions

Main function is lubrication and cleansing oral cavityInitiation of starch digestionImmunologicalHCO3 retards growth of acidophilic bacteriaMaintenance of dentition (Ca, Po4, Mg)Normal outflow is 1-2L/dayparotid gland is the largest, provides only 25% of the total salivary volume

Salivary hypofunction– Candidiasis– Lichen Planus– Burning Mouth– Aphthous ulcers– Dental caries– Xerostomia not reliable

Effects of Aging

• Total salivary flow independent of age• Acinar cells degenerate with age• Submandibular gland more sensitive to

metabolic/physiologic change• Unstimulated salivary flow more greatly

affected by physiologic changes

Diseases of parotid gland

Congenital

Aplasia or atresia

Acquired

Infective

Mumps

Bacterial sialadentitis

Autoimmune

Sjögren's syndrome

Inflammatory

sialadenitis

Neurological

Frey's syndrome

Neoplastic

Salivary gland neoplasm

Idiopathic

Sialolithiasis

Sialadenosis

Applied aspect

Acute bacterial parotitis

most often caused by a bacterial infection of Staphylococcus aureus but may be caused by any commensal bacteria.

It often occurs in the setting of debilitation, dehydration, and poor oral hygiene, particularly among elderly postoperative patient

Mumps

is 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 prodromal 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.

Sjögren's syndrome : 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

Sialolithiasis a condition where a calcified mass forms within a salivary gland

•Pain, which is intermittent, and may suddenly get worse before mealtimes•, and then slowly get better. •Swelling of the gland, also usually intermittent, •Tenderness of the involved gland•Erythema

•Pus discharging from the duct (infection). •Cervical lymphadenitis

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

o Warmth

o Redness of the face

as a result of salivary stimulation by the smell or taste of food

FREY’S SYNDROME

Salivary Gland Tumors

pleomorphic adenomas originate from the intercalated duct cells and myoepithelial cells

oncocytic tumors originate from the striated duct cells

acinous cell tumors originate from the acinar cells,

Mucoepidermoid tumors and squamous cell carcinomas develop in the excretory duct cells.

Differential Diagnosis of Parotid Gland Enlargement

Lymphoma

Actinomycoses

Cat-scratch disease

Sjogren’s syndrome

Viral infection

Referances Grays human anatomy, 14th edition: Elsevier publications

B.d churasia’ human anatomyvol:3

Shafers text book of oral pathology & microbiology, 6th edition

Davidson’s text book of general medicine 18th edition

Thanking you

Guided by-

Dr. Basavaraj kallalli ( dean & HOD)

Dr. kamala.R.

Dr. swaroop

Dr. shurthi