Anatomy of the Parotid Gland

8/20/2019 Anatomy of the Parotid Gland

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Anatomy of the ParotidAnatomy of the Parotid

GlandGland


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Parotid Gland

Is the largest of the major salivary

glands, It is a mainly serous gland It is a

large, irregular, lobulated gland which

extends from the zygomatic arch to theupper part of the neck, where it overlaps

the posterior belly of digastric and the

anterior border of sternocleidomastoid.


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Anteriorly the gland overlaps masseter and a small, usuallydetached accessory parotid lies above the parotid duct on theaponeurotic part of masseter.

he gland extends below the external acoustic meatusposteriorly onto the mastoid process. In transverse section the gland is wedge!shaped, occupying the gap between theramus of the mandible and the mastoid and styloid

processes of the temporal bone, and reaching close to thelateral wall of the oropharynx.

"n accessory parotid gland usually lies on the masseter

between the duct and the zygomatic arch. #everal smallducts open from it into the parotid duct. It and the duct

lie on the aponeurotic part of the surface of the masseter

muscle.


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he Parotid Gland has three surfaces$%ateral uperficial', Posteromedial ( "nteromedialsurfaces.

Posteriorfacial vein

)xternal ca

rotid

artery

Portion behind

styloid process

#uperficial temporal

artery

*axillary artery

Portion anterior to

styloid

Impression for

the mandible

Impression for

#tyloid process

Parotid

tensen' +uct

Parotid tensen' +uct

Impression for *astoid process


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he lateral &superficial' surface of the gland is

covered by skin and superficial fascia. heinvesting layer of deep cervical fascia splits to

envelope the gland and form the Parotid

capsule.he acial nerve branches penetrate the fascia

as they proceed peripherally to inervate

overlying facial muscles.


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he great auricular nerve supplies the fascia

superficial and deep to the parotid gland, and

transmits the pain caused by stretching of thefascial envelope when acute enlargement of the

gland occurs as in mumps.


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%eft Parotid )xposure

"nt.Post.

-ut ends of Great auricular nerve

sacrificed during parotid surgery

Parotid gland

#ternomastoid

muscle


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he anteromedial surface is grooved by the posterior

border of the mandibular ramus, and is related to the

masseter and medial pterygoid muscles which are

attached to the ramus.

he anterior edge of this surface meets the lateral

surface over, as well as below, the masseter forming the

irregularly convex anterior border of the gland.

he parotid duct and the facial nerve branches

emerge from the anteromedial surface and run forwards

deep to the anterior border. he terminal branches ofthe external carotid artery &superficial temporal and

maxillary' leave this surface further back.


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"nteromedial #urface of Parotid gland


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he posteromedial surface is in contact with themastoid process with its attachedsternocleidomastoid and posterior belly of

digastric muscles.*ore medially, the styloid process and itsattached muscles &stylohoid, stylopharyngeus

and styloglossus' separate the gland from thecarotid sheath and its contained internal jugularvein and internal carotid artery.

he external carotid artery enters the gland

through the lower part of this surface.he facial nerve trunk, or its temporofacial andcervicofacial divisions, enter the gland between

the mastoid and styloid processes.


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Posteromedial surface of parotid gland


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*edial relations of the Parotid gland &parotid bed'


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#tructures passing through the gland

acial nerve ( its terminal branches

/etromandibular vein

)xternal -arotid artery ( its two terminal branches

0ranches of the Great auricular nerve


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1ithin the gland the branches of the facial nerve run in different directions corresponding with theirdestinations, i.e. scalp, eyelids, mid!face, lower

face and neck, and they do so in different(superficial to deep) planes. There is nospecific, developmentally determined plane inwhich the facial nerve branches pass betweensuperficial and deep lobes of the gland$ theparotid is an integral gland, not divided intolobes. 1ithin the gland the nerve branches

communicate with each other, forming aplexiform arrangement that lies superficial tothe retromandibular vein, which in turn issuperficial to the external carotid artery.


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he retromandibular vein is formed within the

parotid by the confluence of the superficial

temporal and maxillary veins.

he retromandibular vein emerges from the

lower part &pole' of the gland and divides into an

anterior branch which joins the facial vein and a

posterior branch which joins the posterior

auricular vein to form the external jugular vein$


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The parotid d ct (of tensen) abo t 2 cm long passes for ards across the


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The parotid duct (of tensen), about 2 cm long, passes forwards across the

masseter and turns around its anterior border to pass through the buccal fat

pad and pierce the buccinator .

he duct opens on the mucous membrane of the cheek opposite the second

upper molar tooth.


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he site of the orifice of the right parotid

duct is indicated by the bloody

discharge emanating from it in a patient

with a malignant parotid tumour. In the

absence of a discharge, the tiny orificeis barely visible.

!l d l


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!lood supply

0ranches from the external carotid artery supply

the gland. 3enous return is to the retromandibular

vein.

"ymph drainage

%ymph drains to the preauricular &parotid' nodesand thence to nodes of the upper group of deep

cervical nodes.


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#erve supply


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#erve supply

ecretomotor fibres arise from cell bodies in the otic ganglion

and reach the gland through the auriculotemporal nerve.

"s it passes backwards along the mandibular neck and ascendsbehind the temporomandibular$oint, the auriculotemporal nerveis in contact with the anteromedial surface of the gland, whichispenetrated by filaments from the nerve. he preganglionic

fibres arise from cell bodies in the inferior salivary nucleus in

the medulla, and travel by way of the glossopharyngeal nerve,its tympanic branch, the tympanic plexus and the lesser petrosalnerve to the otic ganglion.

ympathetic (vasoconstrictor) fibres reach the gland from

the superior cervical ganglion by way of the plexus on the

external carotid and middle meningeal arteries.


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Anatomy of the Parotid Gland