Anatomy and significance of parotid gland

1. PAROTID GLAND
The parotid gland is the largest of the three pairs of
salivary glands.
It is a serous salivary gland.
It is weight about 25 g.
 The parotid gland is the largest major salivary
glands.
 It is a serous salivary gland.
 It is weight about 25 g.
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3. LOCATION
• The parotid gland lies in the
pyramidal fossa , which has
following boundaries :
Anteriorly - posterior
border of the ramus of
mandible.
Posteriorly - mastoid
process and
sternocleidomastoid
Superiorly - external
acoustic meatus.

4. PAROTID CAPSULE
• The investing layer of the deep
cervical fascia forms the parotid
capsule.
• The fascia splits to enclose the
gland.
Attachments :
• Superficial lamina - zygomatic arch
• Deep lamina –styloid process and
tympanic plate of the temporal
bone
• The deep lamina, extending
between the styloid process and
the mandible, is thickened to form
the stylomandibular ligament.
• The stylomandibular separates the
parotid gland from the
submandibular salivary gland.

5. EXTERNAL FEATURES
The gland resembles a
three-sided inverted pyramid.
• It has
- An apex
- Base or Superior surface
- 3 surfaces:
- Superficial surface.
- Anteromedial surface.
- Posteromedial surface.
- 3 borders:
- Anterior.
-Posterior.
-Medial.

6. Apex:
• It projects downwards
overlapping the posterior
belly of digastric and
reaches the carotid
triangle.
Structures passing:
1. Cervical branch of
the facial nerve.
2. Anterior and
posterior divisions of
retromandibular vein.

7. Base :
• It is concave and related
to the external acoustic
meatus and posterior
aspect of
temporomandibular
joint.
Structures passing :
• Superficial temporal
vessels
• Auriculotemporal nerve.

8. Superficial Surface:
• It lies between anterior
and posterior border.
• It is covered from
superficial to deep by :
1. Skin.
2. Superficial fascia
containing greater auricular
nerve, superficial parotid
lymph nodes, and platysma.
3. Parotid fascia.

9. Anteromedial Surface:
• It lies between anterior and
medial border.
• It is deeply grooved by the
posterior border of the
ramus of the mandible.
• It is related to:
1. Masseter.
2. Medial pterygoid.
3. Posterior border of the
ramus of the mandible.
4. Lateral aspect of the
temporomandibular joint.
Structures passing :
- Maxillary vessels

10. Posteromedial Surface:
• It lies between posterior
and medial border.
• It is related to :
1. Mastoid process,
sternocleidomastoid, and
posterior belly of digastric.
2. Styloid process
and styloid group of
muscles.
Structures passing :
1. Facial nerve trunk .
2. External carotid artery.

11. Anterior Border:
• It separates the superficial surface
from the anteromedial surface.
• It rest on the masseter muscle.
Structures passing (from above
downward):
1. Temporal branch of the facial
nerve
2. Zygomatic branch of the facial
nerve.
3. Transverse facial vessels.
4. Upper buccal branch of the
facial nerve.
5. Parotid duct.
6. Lower buccal branch of the
facial nerve.
7. Marginal mandibular branch of
the facial nerve.

12. Posterior Border:
• It separates the
superficial surface from
the posteromedial
surface.
• It rest on the
sternocleidomastoid
Structures passing:
• 1. Posterior auricular
vessels.
• 2. Posterior auricular
branch of the facial nerve.

13. Medial Border:
• It separates the
anteromedial surface from
the posteromedial surface.
• It is related to the lateral
wall of the pharynx

14. STRUCTURES PRESENT
WITHIN THE PAROTID
GLAND
• From superficial to
deep these are:
1. Facial nerve.
2. Retromandibular
vein.
3. External carotid
artery.
4. Deep parotid lymph
nodes.

15. Facial nerve :
• It enters the gland through
the posteromedial surface
and divides into five
terminal branches .
• Temporal , Zygomatic,
Buccal and Marginal
mandibular branch leave
the gland through its
anterior border.
• The Cervical branch leave
the gland through its apex.
• The five terminal branches
of the facial nerve radiate
like a goose-foot .
• Such branching pattern of
the facial nerve is termed
pes anserinus.

16. Retromandibular vein :
• The retromandibular vein
is formed within the gland
by the union of the
superficial temporal and
maxillary veins.
• In the lower part of the
gland, the vein divides
into anterior and
posterior divisions which
emerge at the apex of the
gland.

17. External carotid artery:
• The external carotid artery
enters the gland through the
posteromedial surface.
• Within the gland it divides into
superficial temporal and
maxillary arteries.
• The superficial temporal leave
the gland through its base and
maxillary artery through its
anteromedial surface.
• Posterior auricular artery leave
the gland through its posterior
border.
• The transverse facial artery,
branch of superficial temporal
artery emerges through the
anterior border of the gland.

18. Parotid Duct (Stenson’s Duct)
• Parotid duct is about 5 cm long
and emerges from the middle of
the anterior border of the gland.
Course:
• After emerging from the gland, it
runs forward over the masseter
muscles.
Relations on masseter muscle:
Superiorly:
- Accessory parotid gland
- Upper buccal branch of the
facial nerve
- Transverse facial vessels
Interiorly:
- The lower buccal branch of the
facia nerve.

19. • At the anterior border of
masseter, it turns inwards,
and piercing the following
structures
- buccal pad of fat
- buccopharyngeal fascia
- buccinator muscle.
• After piercing the buccinator
muscle, the parotid duct runs
forwards between buccinator
and the buccal mucosa.
Opening of the duct:
• Finally, the duct opens into
the vestibule of mouth
opposite the crown of upper
second molar teeth.

20. NERVE SUPPLY:
• Parasympathetic
• Sympathetic
• Sensory
1. Parasympathetic (secretomotor) supply :
Inferior salivatory nucleus -
glossopharyngeal nerve - tympanic branch
of glossopharyngeal (Jacobson’s nerve)-
tympanic plexus - lesser petrosal nerve -
relay into otic ganglion - Postganglionic
fibres - auriculotemporal nerve to supply
the parotid gland.
2. Sympathetic supply:
• It is derived from sympathetic plexus
around external carotid artery formed by
postganglionic fibres derived from
superior cervical ganglion.
• The sympathetic fibres are vasomotor.
3.Sensory supply:
It is derived from:
(a) Auriculotemporal nerve.
(b) Great auricular nerve

21. BLOOD SUPPLY:
• Arterial supply - External
Carotid Artery
• Venous drainage - External
jugular veins.
LYMPHATIC DRAINAGE:
• Afferent - superficial and
deep parotid lymph nodes.
• Efferent - jugulodigastric
lymphnode.

22. APPLIED ANATOMY
1.Parotid swellings are very painful due to the unyielding
nature of the parotid fascia.
2.Mumps:
• It is an infectious disease of parotid caused by
paramyxovirus.
• Mumps can cause complications in the adults like
orchitis, pancreatitis and oophoritis.
3. A parotid abscess is best drained by horizontal
incisions known as Hilton's method.

23. 4. Frey’s syndrome:
• Penetrating wounds of the parotid gland may damage
auriculotemporal and great auricular nerves.
• During regeneration the secretomotor fibres of
auriculotempora joints with great auricular nerves.
• Thus when a person eats beads of perspiration appears
on parotid region.
5. parotid sialogram:
• The parotid duct can be demonstrated radiologically by
injecting radio-opaque dye.