parotid glands by dr parthsarthi gautam, mds
DESCRIPTION
parotid gland, intro. ,def., classificatn,anaomy, dev. histology, dd, function,referances,TRANSCRIPT
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