Anatomy of

Salivary Glands

Embryology

Salivary glands develop as outgrowths of buccal epithelium.Parotid – ectodermal in origin

Submandibular& Sublingual – endodermal in origin

Parotid – 4th Wk of gestationSubmandibular – 6th Wk of gestationSublingual – 9th Wk of gestation

IntroductionSalivary Gland is any cell or organ discharging a secretion into the oral cavity.

Major and minor Salivary Glands

Major (Paired)

Parotid Submandibular

SublingualMinor

Those in the Tongue, Palatine Tonsil, Palate, Lips and Cheeks

•Main function of Salivary Gland-

secretion of saliva

•Daily secretion -800 to 1500 ml

•pH : 6-7

Saliva Compositon

Water (99.5%) Solid (0.5%)

Organic Inorganic

PtyalinMucin

LysozymeIgA

Lactoferrin

Na+K+

Ca+Cl-

HCO3Mg

Functions of Saliva

Keep the mouth moistAids in swallowingAids in speechKeeps the mouth and teeth cleanAntimicrobial actionDigestive functionBicarbonate acts as buffer

Parasympathetic stimulation - profuse secretion of watery

saliva

Sympathetic stimulation - scanty viscous secretion

Sympathetic supply comes from cervical sympathetic chain along the blood vessels

Salivatory nuclei are excited by

Taste and tactile stimuli from tongue and other areas of mouth and pharynx

Stimuli from esophagus and stomach (due to stimulation of vagal afferent fibers

(unconditioned reflex)

Stimuli arising from higher centers of brain due to sight, smell or thought of food

(conditioned reflex.)

Largest salivary paired gland )weighs15gms(

Secretions of which is serous in nature

2 lobes

1)Superficial

2)Deep

Site

Angle of Mandible

Sternomastoid

Auricle

Head ofMandible

Middle ofMasseter m.

2 cm belowAngle ofMandible

MastoidProcess

Surface Anatomy of Parotid Duct

Tragus ofthe ear

Midway between the ala of the nose

and the angle of the mouth

Middle ⅓ of the horizontal line

RELATIONSRELATIONS

1. Superficial Temporal vessels.Auriculotemporal nerve.

2. Cartilaginous part of External Auditory Meatus.

3. Temporal branch of Facial n.

Upper Part

1. Cervical branch of Facial n.

2. Retromandibular vein.

3. Posterior belly of digastric.

4. External Carotid artery.

Lower Part

• Zygomatic branch of Facial n.

• Transverse Facial artery.

• Buccal branch of Facial n.

• Accessory Parotid gland.

• Parotid duct.

• Mandibular branch of Facial n.

Anterior Border

1. Great Auricular nerve.

2. Parotid lymph nodes.

3. Skin and Fascia

Lateral Surface

1. Ramus of the mandible.

2. Masseter muscle.

3. Medial pterygoid muscle

Antero-Medial Surface

1. Mastoid process

2. Sternomastoid muscle

3. Posterior belly of Digastric

4. Styloid process and the muscle & ligaments attached to it.

5. Internal carotid artery & Internal jugular vein (carotid sheath).

Postero-Medial Surface

1. External carotid artery

2. Retromandibular vein

3. Facial nerve –enters the gland posteromedially,and divides into terminal branches within gland,and leaves the gland through anteromedial surface.

Structures within the Gland

Capsule

1.False Capsule1.False Capsule

Capsule

1.False Capsule

2.True Capsule

1.False Capsule

2.True Capsule

Accesory PartSemidetached part of the gland, which lies just above the parotid

duct

Semidetached part of the gland, which lies just above the parotid

duct

Parotid Duct5 cm long & emerges from

the anterior border & runs superficial to masseter m.

5 cm long & emerges from

the anterior border & runs superficial to masseter m.

•At the anterior border of masseter it pierces

•Buccal pad of fat•Buccopharyngeal fascia•Buccinator Muscle

•It opens into the vestibule of mouth opposite to the 2nd

upper molar

ARTERIAL SUPPLY

External Carotid Artery

Venous Drainage

Retromandibular Vein drain into the internal jugular vein

LYMPHATIC DRAINAGE

Lymph first drains into parotid nodes and then upper deep cervical nodes

Nerve Supply

1. Sensory:

a. Gland:

Auriculotemporal nerve

a. Capsule:

Great Auricular nerve

Nerve Supply

2. Sympathetic:

From the sympathetic plexus around the external carotid.

3. Parasympathetic:

The preganglionic secretomotor fibers arise from the inferior salivary nucleus in the medulla oblongata.

Joins the glossopharyngeal nerve (9th cranial) , tympanic branch ,tympanic plexus,Lesser Petrosal nerve

Enters the foramen ovale to relay in the otic ganglion

The post ganglionic fibres pass through auriculotemporal nerve through which they reach the gland

MedullaOblangata

InferiorSalivaryNucleus

Glossopharyngeal n.

TympanicPlexus

LesserPetrosal n.

OticGanglion

Auriculotemporal n.

Frey syndrome

Also called as auriculotemporal nerve syndrome or gustatory sweating

It is condition wherein sweating in the area of distribution of ATN occurs,which is caused by a stimulus to secretion of saliva.

It is thought to be the result damage to ATN post ganglionic parasympathetic fibres from otic ganglion become united to sympathetic fibres arising from superior cervical ganglion going to supply sweat gland

Surgical approches

Pre auricular

Submandibular

Combination of both

SubmandibularGland

SubmandibularGland

SiteAnterior part of Digastric triangle,

It is roughly j-shaped

Mixed secretion but predominantly serous

Parts1. Superficial part

2. Deep part

3. Submandibular duct

Superficial partDeep part

Submandibular duct

Superficial Part Wedge shaped, extending:Posteriorly: to the angle of mandible.Superiorly: to mylohyoid line of mandible.Inferiorly: it overlaps the 2 bellies of digastric m

Relations1. Inferolateral surface: related to skin, superficial fascia )containing

platysma, cervical branch of facial n., . facial vein, Lymph Nodes( & deep fascia.

2. Lateral surface: related to body of mandible, facial artery, mylohyoid nerve & artery

3. Medial surface: related to 2 muscles )mylohyoid & hyoglossus( & 2 nerves )lingual & hypoglossal(.

Deep PartSmall part lying deep to mylohyoidSuperficial to hyoglossusBetween lingual nerve above & hypoglossal nerve

below

Mylohyoid

Lingual n.

Submandibluar duct

Whartons duct5 cm long

Emerges at the anterior end of deep part of the glandRuns forwards on hyoglossus b/w lingual and hypoglossal NAt the ant. Border of hyoglossus it is crossed by lingual nerveOpens in the floor of mouth at the side of frenulum of tongue

Blood Supply

ArteriesBranches of facial and lingual arteries

VeinsDrains to the common facial or lingual veins

LymphaticsDeep Cervical Nodes via submandibular nodes

Nerve Supply

1.Sensory: Lingual nerve

2.Sympathetic: Plexus around the facial artery

3.Parasympathetic:Chorda tympani from Facial nerve

Sublingual Salivary Glands

smallest of the three glands

weighs nearly 3-4 gm

Lies beneath the oral mucosa in contact with the sublingual fossa on lingual aspect of mandible. Mixed secretion but predominantly mucous

RelationsAbove the mylohyoid below the mucosa of floor of mouthMedial to sublingual fossaLateral to genioglossus

DuctDucts of Rivinus

8-20 ductsLargest of all,sub lingual duct(bartholin duct) joins sub mandibular duct to drain through sublingual caruncle,Most of them open directly into the floor of mouth

Blood supplyArterial from sublingual and submental arteriesVenous drainage corresponds to the arteries

Nerve SupplySimilar to that of submandibular glands( via lingual nerve , chorda tympani and sympathetic fibers)

DISORDERS OF SALIVARY GLAND

CLASSIFICATION OF SALIVARY GLAND DISORDERS

A) Developmental disorders

Aberrancy

Aplasia & Hypoplasia

Hyperplasia

Atresia

Accessory ducts

Diverticuli

Congenital fistula

B( Functional disordersSialorrhoeaXerostomia

C( Obstructive disordersSialolithiasisMucus plugStricture & stenosisForeign bodiesExtra ductal causes

D( Cyst

Mucocele

Ranula

E( Asymptomatic enlargement

Sialosis

Allergic

Associated with malnutrition and alcoholism

F( Infection

Viral

Bacterial

Mycotic

G( Autoimmune disorders

Sjogren’s syndrome

Mikulicz’s disease

Uveoparotid fever

Recurrent non specific parotitis

Blue pigmented swelling

Plunging Ranula Ranula

Non-invasive investigationsRadiographsComputerized TomographyUltrasound scanningMagnetic resonance imagingSingle Photon emission Computed Tomography

Invasive InvestigationsBiopsyFine needle Aspiration cytology

Sialography

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