Parotid Gland Flashcards
Type
Largest salivary gland
Shape
Wedge shaped
Site
Lies in depression between mandible ramus and mastoid process
Extent
- Forwards: over masseter
- Backwards: over part of sternomastoid
- Upwards: external auditory meatus
- Downwards: 2cm below and behind mandible angle
Parotid fascia
Capsule of deep cervical fascia enclosing gland
Parts
- Main superficial part
- Deep part
- Small accessory part
Main superficial part
Wedged between
1. Anterior: mandible ramus
2. Posterior: mastoid process and sternomastoid
Deep part
Deep to mandible
Small accessory part
Above parotid duct on masseter
Surfaces
- Lateral surface
- Anteromedial surface
- Posteromedial surface
Lateral surface contents
- Skin
- Fascia
- Great auricular nerve
- Superficial parotid lymph nodes
Anteromedial surface contents and shape
Extremely concave
1. Ramus of mandible
2. Masseter muscle
3. Medial pterygoid muscle
Posteromedial surface processes (2)
- Matoid
- Styloid
Posteromedial surface muscles attached to mastoid process (2)
- Superficially: Sternomastoid
- Deeply: posterior belly digastric
Posteromedial surface attached to styloid process
3 muscles and 2 ligaments
Posteromedial surface blood vessels (2)
- ICA
- IJV
With last 4 cranial nerves in between
2 structures enter Posteromedial surface
- Facial nerve
- ECA
Ends
- Upper end
- Lower end
Upper end shape and relation
Concave
Related to external auditory meatus
Upper end contents (3)
- Superficial temporal artery
- Superficial temporal vein
- Auriculotemporal nerve
Lower end site
2cm below and behind angle mandible overlapping posterior belly digastric
Structures leaving lower end (2)
- Cervical branch of facial nerve
- Anterior and posterior divisions of posterior facial (retromandibular) vein
Borders
Anterior border
Structures leaving anterior border
- Parotid duct: with accessory part above it
- Transverse facial artery: above duct
- Temporal branch facial nerve: above duct
- Zygomatic branch facial nerve: above duct
- Buccal branch facial nerve: below duct
- Mandibular branch facial nerve: below duct
Surface anatomy: upper end
- Concave upwards around external auditory meatus
- Line from auricle tragus (mandible head) to middle mastoid process
Surface anatomy: anterior border
Line from
1. Tragus
Downwards and forwards to
2. Middle of masseter
Downwards and backwards to point 2cm below and behind
3. Mandible angle
Surface anatomy: posterior border
Line from
1. Mastoid process
Point 2cm below and behind
2. Mandible angle
Running along
3. Anterior sternomastoid border
Parotid duct
Thick walled with narrow lumen 5cm long
Parotid duct site
Gland anterior border passing horizontally on Masseter below zygomatic arch
Parotid duct: structures pierced
At Masseter anterior border
It pierces:
1. Buccal pad of fat
2. Buccopharyngeal facia
3 . Buccinator
4. Buccal mucosa
It then opens in vestibule opposite 2nd molar
Parotid duct surface anatomy
Middle 1/3 of line from tragus to point midway between nose ala and red margin of upper lip
Structures within the parotid gland (5)
- Facial nerve
- Posterior facial vein
- ECA
- Deep parotid lymph node
- Auriculotemporal nerve
Facial nerve relation to parotid gland
- Enters Posteromedial surface close to stulomastoid foramen
- Runs as most superficial structure
- End by dividing into 5 terminal branches
Facial nerve terminal branches in parotid gland
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
Posterior facial vein relation in parotid gland
- Formed inside gland behind mandible neck by union of maxillary and superficial temporal veins
- Descends between facial nerve and ECA
- Leaves gland through its lower end as anterior and posterior divisions
ECA relation to parotid gland
- Passes deep to gland lower end entering gland through its Posteromedial surface
- Run as deepest structure
- Ends opposite mandible neck by dividing into 2 terminals
ECA terminal branches in parotid gland (2)
- Maxillary artery
- Superficial temporal artery
Deep parotid lymph node site in parotid gland
In gland substance around blood vessels
Auriculotemporal nerve in parotid gland
Runs a short course
Parotid gland nerve supply
- Sensory
- Sympathetic
- Parasympathetic
Sensory nerve supply in parotid gland
- Auriculotemporal nerve
Sympathetic nerve supply in parotid gland
Plexus around ECA and MMA
Parasympathetic nerve supply in parotid gland
Glossopharyngeal nerve
Glossopharyngeal nerve course and origin
- Preganglionic fibers arise from inferior salivary nucleus of medulla
- Pass with tympanic branch of Glossopharyngeal nerve
- Enter middle ear
- From tympanic plexus
- Gives lesser superficial petrosal nerve
Lesser superficial petrosal nerve course and relay
- Leaves skull via foramen ovale
- Relay in Otic ganglion
- Posterior ganglionic fibers join Auriculotemporal nerve to reach gland
Parotid gland blood supply
- Atrial: superficial temporal artery
- Venous:
- posterior facial (retromandibular) vein
- external jugular vein
Lymph drainage parotid gland
- Superficial parotid node
- Deep parotid node
Drain in deep cervical nodes
Applied anatomy: inflammation of gland (parotitis)
Infection reaches gland from mouth through duct or blood stream.
Patient complains of:
1. Parotid swelling
2. Raised or everted auricle lobule
3. Severe pain (due to stretch of tight parotid capsule)
Increases during mastication (due to close relation of gland to TMJ
Applied anatomy: parotid tumors
Affects gland superficial to facial nerve branches
Benign: will not affect nerve
Malignant: compresses and invade the nerve leading to facial nerve paralysis