Transcript SALIVARY GLANDS

Parotid Salivary gland
• It is the largest of all salivary
glands.
 Shape:
• Irregular pyramid in shape.
 Position:
• It lies below the external
acoustic meatus. It wedges
between the ramus of the
mandible and sternomastoid
muscle.
• It extends upwards till the level
of zygomatic arch and down to
the angle of the mandible.
• The gland partially
overlaps the masseter
muscle.
• A small semi-detached
part of the gland lies
between the
zygomatic arch and
the parotid duct which
is called: accessory
part of the parotid
gland.
• The gland has:
• 2 ends; a superior end
(surface), an inferior
end which extends to
to the level of angle of
mandible.
• 3 surfaces; superficial
(lateral), anteromedial
and posteromedial.
• The gland is covered
by a capsule derived
from deep cervical
fascia.
Main structures within the
substance of the gland:
• From superficial to deep, they are:
1. Facial nerve and branches.
2. Retromandibular vein and its two
divisions, maxillary vein, superficial
temporal vein..
3. External carotid artery and its two
terminal branches.
Facial nerve
• It is the most superficial structure.
• It enters the gland through its posteromedial
surface.
• It breaks within the gland into terminal branches
that leave it through; upper end, lower end and
anteromedial surface.
• These terminal branches are 5;
Temporal, zygomatic, buccal, marginal mandibular
and cervical.
Other structures within the
gland:
1. Auriculotemporal nerve.
2. Posterior auricular artery.
3. Preauricular lymph nodes.
Parotid duct:
• The duct is about 5 cm in
length.
• It arises from anterior
border of the gland.
• It runs on the masseter
muscle.
• At the anterior border of
masseter it runs medially
to pierce the buccinator
muscle and mucosa to
open in the vestibule of
the mouth.
• Opening of parotid duct:
It opens in the vestibule of
the mouth opposite the
upper second molar tooth.
• Surface anatomy:
The duct is represented by
the middle 1/3 of the line
between a point on the
lower border of tragus of
ear and a point midway
between the ala of nose
and red margin of the
upper lip.
Blood supply:
• Arterial:
External carotid artery and its terminal branches
within the gland.
• Venous:
Into the retromandibular vein.
• Lymph drainage:
Into Preauricular (parotid), superficial
cervical and deep cervical lymph nodes.
Nerve supply:
• Sensory supply:
From Auriculotemporal nerve.
• Sympathetic supply:
From the plexus around external carotid
artery.
• Parasympathetic supply:
Otic ganglion.
Parasympathetic supply:
• From inferior salivary
nucleus in brain stem.
• To glosspharyneal nerve.
• To its tympanic branch that
breaks into tympanic plexus
on the tympanic membrane.
• The fibres then carried by
lesser petrosal nerve to relay
in otic ganglion.
• Postganglionic fibers reach
the gland via
Auriculotemporal nerve.