The parotid gland is the largest salivary gland that secretes serous fluid. It is located below and in front of the external ear. The facial nerve passes through the gland and divides into branches that innervate facial muscles. The parotid duct transports saliva from the gland to the mouth. The facial nerve exits the skull through the stylomastoid foramen and enters the parotid gland, where it divides into branches. Bell's palsy is caused by compression of the facial nerve at the stylomastoid foramen, resulting in an inability to close the eye or move parts of the face.

1. Parotid Gland & Extracranial part of
facial nerve
By
Dr: Joseph Amin
M.D of anatomy & embryology
Faculty of medicine-Zagazig university
Jaaziz@zu.edu.eg
joseph.Aziz@su.ed.eg

2. Parotid Gland
Par=beside, Otic = ear
 The largest major salivary gland, its secretion is pure serous.
 It weighs 15-25 gm.
 Site:
Below the external auditory meatus overlying the ramus of mandible and masster muscle
anteriorly & mastoid process and sternomastoid muscle posteriorly.

3. N.B. Accessory part of Parotid
Small detached part that lies above the parotid duct.
 Shape:
 Capsule:
Parotid gland has 2 capsules:
inner (true) capsule
outer (false) capsule derived from investing fascia of the neck.
Parotid is pyramidal in shape, it has
Apex & Base,
3 surfaces (lateral- anteromedial-posteromedial)
3 borders (anterior – posterior – medial).

4.  Structures inside parotid gland:
F: facial nerve:
A: Auriculotemporal nerve:
R: Retromandibular vein
E: External caroitd artery
D: deep parotid lymph node
From superficial to deep

5. F: facial nerve: it enters the parotid through its posteromedial surface and divides inside it into 5
terminal branches (Temporal-Zygomatic-Buccal-Mandibular-Cervical)
A: Auriculotemporal nerve: it enters the parotid through its anteromedial surface and exits from
the upper end
R: Retromandibular vein, it is formed inside parotid by the union of superficial temporal and
maxillary veins. It leaves the parotid from its apex by dividing into anterior and posterior divisions
E: External caroitd artery, it enters the parotid through its posteromedial surface and divides
inside it into its two terminal branches: superficial temporal & maxillary arteries
D: deep parotid lymph node

6.  Base (upper end): concave, related to the external auditory meatus.
It gives passage to superficial temporal vessels & auriculotemporal nerve.
 Apex (lower end): just behind and below the angle of the mandible.
It gives passage to the cervical branch of facial nerve & the two divisions of retromandibular vein.
 Lateral surface: related to skin, superficial fascia that contains superficial parotid LN & great
auricular nerve
Great auricular nerve
 Relations:

7.  Anteromedial surface: related to Masseter, Mandibular ramus & Medial pterygoid muscle.
It gives passage to maxillary vessels & auriculotemporal nerve.
 Posteromedial surface: related to mastoid process, sternomastoid muscle & posterior belly of
digastric) - Styloid process and 5 structures attached to it (stylohyoid, stylopharyngeus,
styloglossus muscles - stylomandibular & stylohyid ligaments) - Carotid sheath (ICA – X – IJV).
It gives passage to External carotid artery & Facial nerve
 Anterior border: gives passage to temporal, zygomatic, buccal & mandibular branches of facial
nerve, transverse facial vessels & parotid duct.
 Posterior border:
 Medial border: related to the wall of the pharynx

8.  Parotid duct (Stensen’s duct):
- At the anterior border of masseter, It turns medially piercing the following structures:
buccal pad of fat, buccopharyngeal fascia, buccinator muscle then passes forward for a short
while between buccinator & mucous membrane. Finally it pierces mucous membrane of the
cheek to open into the vestibule of the mouth opposite the maxillary (upper) 2nd molar tooth.
Opening of parotid duct
- It is about 5 cm in length
- It comes out from the middle of the anterior border
and passes anteriorly on the masseter muscle one finger
breadth below the zygomatic arch.

9.  Nerve supply:
Sympathetic: from plexus around ECA, it produces scanty viscid secretion.
 Sensory: along auriculotemporal nerve (parotid substance) & great auricular nerve (capsule).
Inferior salivatory
nucleus
Solitary nucleus
Ambigous nucleus
Spinal nucleus of TG
Glossopharyngeal
nerve IX
Middle ear (tymbanic plexus) Lesser petrosal nerve
Foramen ovale
Otic ganglion attached to mandibular nerve
P
Pharynx
Tongue
Parasympathetic nerve supply
 Parasympathetic: Inferior salivatory nucleus … > preganglionic parasympathetic fibers pass
along the Glossopharyngeal nerve (9th) … > tympanic branch … > tympanic plexus (inside the
middle ear (tympanic cavity))… > lesser petrosal nerve … > foramen ovale… > otic ganglion
attached to the mandibular nerve… > postganglionic fibers along auriculotemporal nerve …. >
parotid gland, it produces profuse serous secretions
Parasympathetic
Taste
Motor
General sensory

10.  Surface anatomy:
Gland: point (A) ….> head of the mandible (condyle)
point (B) ….> mastoid process
point (C) ….> mandibular notch
point (D) ….> behind angle of the mandible
A-B…..> base
A-C-D ….> ant. Border
B-D…> pos.bodrder
 Blood supply:
- External carotid artery
- Retromandibular vein
Duct: middle 1/3 of a line between
- point on the tragus of the ear (2)
- point midway between ala of the nose and upper lip (1)

11.  Extra cranial part of the Facial nerve
 It exits from the cranial cavity through stylomastoid foramen carrying only motor fibers.
 It then curves forward lateral to styloid process to enters the postermomedial surface of
parotid gland where it lies superficial to RMV & ECA.
 Inside the parotid, it ends by dividing into 5 terminal branches that supply the facial muscles.
 Branches:
Before it enters parotid gland (2)
Inside parotid gland (5)
- Temporal
- Zygomatic
- Buccal
- Mandibular
- Cervical
Temporofacial trunk
Cervicofacial trunk
- Posterior auricular branch, supplies the occipital belly of
occipito-frontalis muscle.
- Nerve to posterior belly of digastric and stylohyoid muscles.

12.  Revise

13.  Applied Anatomy:
 Bell’s palsy (IFP)
Most common form of facial nerve lesion. It occurs due to compression of the facial nerve
at the stylomastoid foramen.
In ability to close the eye
Loss of nasolabial fold
Drooling of saliva
In ability to whistle
Accumulation of food in
the vestibule
Deviation of the mouth
to the healthy side