Date post: | 13-Apr-2017 |
Category: |
Education |
Upload: | kanato-assumi |
View: | 1,097 times |
Download: | 2 times |
SALIVARY GLANDS ANATOMYPresenter: DR. Kanato. T
INTRODUCTIONINTRODUCTION
The salivary glands are exocrine glands, glands with ducts, that produce saliva and pour their secretion in the oral cavity
Major (Paired) Parotid Submandibular Sublingual
MinorThose in the mucosa of lips, cheeks, palate, floor of mouth and oropharynx.
Functions of Saliva• Keeps the mouth moist• Aids in swallowing• Aids in speech• Keeps the mouth and teeth clean• Antimicrobial action• Digestive function• Bicarbonate acts as buffer
DEVELOPMENT• All major Salivary Gland are derived from oral cavity epithelium.• The development of major salivary glands is thought to consist of
three main stages .1. The first stage is marked by the presence of a primordial anlage
(from the German verb anlagen, meaning to lay a foundation or to prepare) and the formation of branched duct buds due to repeated epithelial cleft and bud development.
2. The early appearance of lobules and duct canalization occur during the second stage.
3. The third stage is marked by maturation of the acini and intercalated ducts, as well as the diminishing prominence of interstitial connective tissue.
MICROSCOPIC ANATOMY• The basic secretory unit is the acinus• The secretory cells are of three types.1. Cells containing small granules are serous and secrete
salivary proteins and enzymes.2. Mucin-producing cells are cylindrical in shape and
contain larger granules producing mucoproteins.3. Seromucinous cells have an intermediate
ultrastructure.Parotid: are mostly serousSubmandibular: mucous & serousSublingual & Minor salivary gland: mostly mucous
PAROTID GLAND
Largest Average Wt - 25gmIrregular lobulated mass lying mainly below the external acoustic meatus between mandible and sternomastoid.On the surface of the masseter, small detached part lies b/w zygomatic arch and parotid duct-accessory parotid gland or ‘socia parotidis’
External Features•Resembles an inverted 3 sided pyramid•Four surfaces1. Superior(Base of the Pyramid)2. Superficial3. Anteromedial4. Posteromedial• Separated by three borders
AnteriorPosteriorMedial
Parotid Capsule• The investing layer of deep cervical fascia forms the
capsule.• Superficial lamina-thick, closely adherent to the gland.• Deep lamina-thin- attached to styloid process, mandible
and tympanic plate.• A portion of deep lamina between styloid process and
mandible is thickened to forms Stylomandibular ligament.
(which separates the parotid from submandibular gland)
Relations• Superior Surface • Concave• Related to • Cartilaginous part of ext
acoustic meatus• Post. Aspect of
temporomandibular joint• Auriculotemporal Nerve• Sup. Temporal vessels
•Apex• Overlaps posterior belly of
digastric and adjoining part of carotid triangle
• Superficial Surface• Covered by • Skin• Superficial fascia containing facial
branches of great auricular N• Superficial parotid lymph nodes and
post fibers of platysma
•Anteromedial Surface•Grooved by posterior border of ramus of mandible
•Related to• Masseter• Lateral Surface of
temperomandibular joint• Medial pterygoid
muscles• Emerging branches
of Facial N
• Posteromedial Surface
• Related • to mastoid process with
sternomastoid and posterior belly of digastric.
• Styloid process with structures attached to it.
• External Carotid A. which enters the gland through the surface
• Internal Carotid A. which lies deep to styloid process
BORDERS
Anterior border
• Separates superficial surface from anteromedial surface.
• Structures which emerge at this border
Terminal Branches of facial nerve
Transverse facial vesselsParotid Duct
• Posterior Border
• Separates superficial surface from posteromedial surface• Overlaps sternomastoid
•Medial Border
• Separates anteromedial surface from posteromedial surface• Related to lateral wall of pharynx
Structures within the parotid gland• Facial Nerve• Retromandibular Vein• External carotid Atery
• Facial Nerve trunk lies approximately 1 cm inferior and 1 cm medial to tragal cartilage pointer of external acoustic meatus.
Surgical Landmarks of Facial Nerve• Tragal cartilage pointer: Facial
verve lies 1–1.5 cm medial and inferior to tragal point.• Tympanomastoid suture: Facial
nerve lies 6–8 mm deep to the suture.• Posterior belly of digastric: The
facial nerve lies between the mastoid and the posterosuperiorpart of the posterior belly of digastric muscle.• Styloid process: Facial nerve lies
on the posterolateral aspect of the styloid process near its base.
Peripheral branches• The following branches may be followed proximally:• Temporal: It bisects a line drawn from tragus to lateral
canthus of eye.• Buccal: It runs 1 cm above and parallel to Stensen’s
duct over the masseter.• Ramus mandibularis: It travels superficial to the facial
vessels 2 cm below inferior border of mandible and 1 cm anterior to angle of mandible.
Parotid Duct
• ductus parotideus; Stensen’s duct
• 5 cm in length
• Appears in the anterior border of the gland
• Runs anteriorly and downwards on the masseter b/w the upper and lower buccal branches of facial N.
•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
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
Surface anatomy of Parotid Duct
• Corresponds to middle third of a line drawn from lower border of tragus to a point midway b/w nasal ala and upperlabial margin
SURFACE MARKINGA)UPPER BORDER OF HEAD OF MANDIBLE
B)JUST ABOVE CENTRE OF MASSETER MUSCLE
C)POSTEROINFERIOR TO THE ANGLE OF MANDIBLE
D)UPPER PART OF ANGLE OF MANDIBLE
Head ofMandible
Middle ofMasseter m.
2 cm belowAngle of
Mandible
MastoidProcess
Blood supply• ArterialBranches of Ext. Carotid A• VenousInto Ext. Jugular Vein• Lymphatic DrainageUpper Deep cervical nodes via Parotid nodes
NERVE SUPPLY• Parasymapthetic NSecretomotor via
auriculotemporal N• Symapathetic NVasomotorDelivered from plexus
around the external carotid artery• Sensory NReach through the Great
auricular and auriculotemporal N
Applied aspects• Parotid swellings are very painful due to the unyielding
nature of the parotid fascia.• The relatively thin fascia covering the apex of the gland
can lead to the spread of sepsis into the parapharyngeal space.• Radiologically, the retromandibular vein is a useful
landmark for the facial nerve, which traverses the gland, superficial to the vein.• The facial nerve is said to divide the gland into a deep
and superficial lobe. This concept is helpful clinically, but is not anatomically based.
Gustatory sweating (Frey's syndrome or auriculotemporal syndrome)• Gustatory sweating (auriculotemporal syndrome)
commonly occurs following parotid surgery or other surgery or trauma that results in opening of the parotid capsule.• Cause by innervation of sweat glands on the face by
regrowing parasympathetic secretomotor axons .• Frey's syndrome is characterized by sweating, warmth
and redness of the face as a result of sweet gland stimulation by the smell or taste of food.
submandibular salivary gland
Submandibular Glands are….
• It is roughly J shaped.• About a size of walnut• Large superficial and small deeper part
continuous with each other around the post. border of mylohyoid
Superficial Part• Situated in the digastric triangle•Wedged b/w body of mandible and mylohyoid• 3 surfaces
• Inferior, Medial, Lateral
Capsule • Derived from deep cervical fascia
• Superficial Layer is attached to base of mandible
• Deep layer attached to mylohyoid line of mandible
Relations • Inferior- covered by
• Skin• Superficial fascia containing
platysma and cervical branches of facial N• Deep Fascia• Facial Vein• Submandibular Nodes
• Lateral surface• Related to submandibluar fossa
on the mandible• Madibular attachment of Medial
pterygoid• Facial Artery
• Medial surface• Anterior part is related
to myelohyoid muscle, nerve and vessels• Middle part -
Hyoglossus, styloglossus, lingual nerve, submandibular ganglion, hypoglossal nerve and deep lingual vein.• Posterior Part -
Styloglossus, stylohyoid ligament,9th nerve and wall of pharynx
• Deep part• Small in size
• Lies deep to mylohyoid and superficial to hyoglossus and styloglossus
• Posteriorly continuous with superficial part around the posterior border of mylohyoid
Submandibular DuctWharton's duct• 5 cm long• Emerges at the anterior end of deep part
of the gland• Runs forwards on hyoglossus b/w lingual
and hypoglossal N• At the ant. Border of hyoglossus it is
crossed by lingual nerve• Opens in the floor of mouth at the side of
frenulum of tongue
Blood supply and lymphatics
• ArteriesBranches of facial and lingual
arteries• VeinsDrains to the corresponding
veins
• LymphaticsDeep Cervical Nodes via
submandibular nodes
Nerve supply• Branches from
submandibular ganglion, through which it receives
Parasymapthetic fibers from chorda tympani
Sensory fibers from lingual branch of mandibular nerve
Sympathetic fibers from plexus on facial A
Applied aspects• The formation of calculus is more common in the
submandibular gland than in the parotid.Because duct is longer and has a larger caliber, and
angulated against the gravity.Secretions are more viscous and have higher calcium and
phosphorous concentration.• For excision of the submandibular salivary gland (for
calculus or tumour), a skin crease incision is as a rule, given more than 1inch( 2.5cm) below the angle of the jaw• A stone in the submandibular duct(wharton’s duct) can
be palpated bimanually in the floor of the mouth and can even be seen if sufficiently large.
Sublingual Salivary Glands
• smallest of the three glands • Almond shaped.• weighs nearly 3-4 gm
• Lies beneath the oral mucosa in contact with the sublingual fossa on lingual aspect of mandible.
Relations •Above
• Mucosa of oral floor.
•Below • Myelohyoid
•Behind• Deep part of
Submandibular gland
• Lateral• Mandible above the anterior part of mylohyoid
line• Medial
• Genioglossus and separated from it by lingual nerve and submandibular duct
Duct • Ducts of Rivinus• 8-20 ducts Most of them open directly
into the floor of mouth• Few of them join the submandibular duct
• Sometimes form a major sublingual duct (Bartholin's duct), which opens with, or near to, the orifice of the submandibular duct.
•Blood supply• Arterial from sublingual and
submental arteries• Venous drainage corresponds to
the arteries
•Nerve Supply• Similar to that of submandibular
glands( via lingual nerve , chorda tympani and sympathetic fibers)
Applied aspects• The structures at risk during dissection of the gland are
the submandibular duct and the lingual nerve.• The duct lies superficially in the floor of the mouth
medial to the sublingual fold, and is crossed inferiorly by the nerve which then enters the tongue• The sublingual artery and vein also lie on the medial
aspect of the gland close to the submandibular duct and lingual nerve.• Common disorder of sublingual salivary gland is ranula.
Minor salivary glands• About 600 to 1,000 minor salivary glands, ranging in
size from 1 to 5 mm, line the oral cavity and oropharynx.• The greatest number of these glands are in the lips,
tongue, buccal mucosa, and palate, although they can also be found along the tonsils, supraglottis, and paranasal sinuses.• Each gland has a single duct which secretes, directly into
the oral cavity, saliva which can be either serous, mucous, or mixed.• The common disorders of minor salivary gland include
mucous retention cyst.
References• Gray's Anatomy, 40th Edition• Scott-Brown’s Otorhinolaryngology, Head and Neck
Surgery 7th edition.• B.D Chaurasia’s Human Anatomy Volume-3, Head &
Neck.• Netter’s Head and Neck Anatomy for Dentistry 2nd
Edition.• ATLAS OF OTOLARYNGOLOGY, HEAD &NECK OPERATIVE
SURGERY by Johan Fagan.
THANK YOU