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Gross Anatomy 9:00-10:00
February 12, 2009
Dr. Zehren
Italicized is before the recording picked up.
I. [S1,2,3] General Remarks
Parotid Region
Scribe: Teresa Kilborn
Proof: Ashley Holladay
Page 1 of 6
a. The parotid is one of three major glands
i. It is described as being In the shape of an inverted pyramid
ii. Wedged between the ear and the mandible
iii. Parotid duct drains the parotid gland into the oral cavity
b. Another major salivary gland is the submandibular gland
i. There is a large superficial portion that lies in the submandibular triangle which is the triangle
bounded by the anterior triangle that is bounded by the anterior belly of the digastrics and the
lower angle of the mandible
ii. It also has a deep part that we haven’t seen. The gland is U-shaped. The deep portion projects
onto the other side of the mylohyoid. It’s from the deep portion that the submandibular duct
leaves the gland and empties into the oral cavity beneath the tongue. You won’t see the deep
potion until we do the floor of the mouth.
c. The third and smallest of the major salivary glands is the sublingual salivary gland.
i. It is elongated and flattened.
ii. Almond sized and shaped.
iii. It rests inferiorly on the mylohyoid muscle
iv. Superiorly it produces a fold of mucosa on the floor of the mouth called the sublingual fold. This is
where the ducts open into the mouth.
II. [S4] Salivary glands (Histology)
a. There are also minor salivary glands as well.
b. This shows histologically that the parotid gland is almost totally serous in terms of its secretions
c. The submandibular is mostly serous, but has some mucous cells in it
d. The sublingual is almost completely mucous secreting gland
III. [S5] Roof of Mouth- Hard and Soft Palates
a. There are minor salivary glands or accessory salivary glands in the palate
b. Several behind the molar teeth
c. Also in the lips. Labial glands and buccal glands in the cheeks.
d. These all contribute to the saliva that is produced.
IV. [S6,7] Parotid Bed (Relationship of the parotid gland)
a. The parotid bed is formed by muscles and bones that surround the gland
b. It is an irregular shaped mold into which the gland fits
c. The bones and muscles are shown here, gland is removed in this diagram
d. Anterior and medially is the posterior border of the ramus of the mandible and that indents the gland
e. There are two muscles related to the anterior medial aspect of the gland (not shown here): masseter
and medial pterygoid
f. Posteriorly and medically are the mastoid process and styloid process and the muscles related to those
processes namely the SCM and posterior belly of the digastric. Coming from the styloid process muscles
including the stylohyoid. The styloid muscles separate the gland from the contents of the carotid
sheath. Superiorly the parotid bed is formed by the external auditory meatus.
V. [S8] Parotid Bed (Horizontal Section)
a. If you take a horizontal section through the parotid bed and gland, you would see this (from atlas).
b. Gland is wedge shaped in lateral and cross section view. Lateral surface is subcutaneous.
c. Points out anterior medial surface and posterior medial surface.
d. The anterior medial surface is indented by the ramus of the mandible and the masseter and the medial
pterygoid muscles which are on either side of the ramus of the mandible. The form the anterior medial
part of the parotid bed.
e. Posterior medial you have the SCM, and posterior belly of the digastrics, the styloid muscles which are
attached more superiorly to the styloid process.
f. The anterior medial and posterior medial borders of the gland meet at the medial border of the gland.
The medial border of the gland is fairly close to the wall of the pharynx.
Gross Anatomy 9:00-10:00
February 12, 2009
Dr. Zehren
VI. [S9] Lateral Pharyngeal Space
Parotid Region
Scribe: Teresa Kilborn
Proof: Ashley Holladay
Page 2 of 6
a. The oral pharynx is just behind the oral cavity.
b. The muscle that forms the wall at this level is the superior constrictor muscle of the pharynx. This
section shows the close relationship between the medial border of the parotid gland to the wall of the
pharynx. You don’t see that from the lateral aspect.
c. The space occupied by the styloid muscle is called the lateral pharyngeal space because it is just lateral
to the pharynx and just medial to the parotid gland.
d. If you get a tumor in the parotid gland then sometimes it will push the gland medially and invade the
lateral pharyngeal space. It will cause a bulging in the wall in the pharynx which can be seen in an oral
exam.
VII. [S10,11] Structures within the Parotid Gland
a. 3 major things penetrate the parotid gland
b. The facial nerve branching within the gland. It’s more superficial
c. Deep to that is the retromandibular vein
d. Deepest of all is the terminal part of the external carotid artery- can follow it into the gland and see its
termination.
VIII. [S12] Facial Nerve (VII) Within Parotid gland
a. Shows how the main trunk of the facial nerve which emerges from the stylomastoid foramen divides
into its terminal branches (TZBMC)
b. They all fan out and go to the muscles of facial expression.
c. They supply motor to the muscles of facial expression.
IX. [S13] Facial nerve Branches and Parotid Gland Sectioned
a. Horizontal section through the gland
b. Mastoid process
c. Ramus of the mandible
d. Medial pterygoid
e. Masseter
f. Main trunk of 7 dividing the gland into a superficial lobe and a deep lobe
g. If there is a tumor in the gland:
i. in the case of a benign tumor it doesn't invade the facial nerve so the surgeon has to remove
the tumor without damaging the branches of 7
ii. Malignant tumors invade 7 and destroy it
iii. Facial nerve sometimes called the hostage of the parotid surgery because it is held hostage by
the parotid gland
X. [S14] Shows how the retromandibular vein is formed within the substance of the gland
a. Formed by the superficial temporal vein which drains the scalp and the maxillary vein is the large vein
draining the infratemporal fossa region.
b. They come together to form the retromandibular vein which runs down and exits the gland as an
inverted “Y”.
XI. [S15] Terminal part of the ECA
a. Like the retromandibular vein it divides and terminates by dividing into superficial maxillary and
temporal arteries. They run with their corresponding veins.
b. You won't see the maxillary artery because it disappears almost immediately deep to the ramus of the
mandible. The most you will see is a few millimeters.
c. The continuation upward- the superficial temporal is easy enough to see
d. The maxillary is going into the infratemporal fossa.
XII. [S16, 17] Parotid Fascia
a. There is a fascia called the parotid fascia
b. Dense fascia
c. It is continuous with the investing layer of deep cervical fascia.
Gross Anatomy 9:00-10:00
February 12, 2009
Dr. Zehren
Parotid Region
Scribe: Teresa Kilborn
Proof: Ashley Holladay
Page 3 of 6
d. It forms the covering to the gland and limits the enlargement of the gland in for ex. mumps (viral
infection of the gland) or obstruction of the parotid duct.
e. It causes pain because you have a swollen gland that is encapsulated in the fascia
f. If you have an obstruction of the oral duct and secretions cannot reach the oral cavity the gland swells
and that is painful
g. Any movement of the mandible with a swollen gland is going to be extremely painful, because the
posterior border of the ramus of the mandible will put pressure on the inflamed gland.
XIII. [S18] There is a thickening of the fascia on the medial part of the parotid fascia
a. It forms the stylomandibular ligament
b. It runs from the styloid process to the angle of the mandible
c. It is a localized thickening of the parotid fascia that separates the parotid gland from the submandibular
gland which lies in part in the submandibular fossa.
XIV.
[S19, 20] Parotid duct (Stenson’s Duct)
a. There are a lot of things that fan out from the margin of the parotid gland.
b. There are vessels like the superficial temporal artery and vein. The auriculotemporal nerve runs with
them. It is a branch of V3. All of those come out the base or superior margin of the gland
c. The branches of 7 fan out. (TZBMC)
d. An artery called the transverse facial artery runs across the masseter and supplements the facial artery
e. The parotid duct comes from the anterior margin of the gland and runs superficial to the masseter
muscle about a finger length below the zygomatic arch. When it reaches the anterior border of the
masseter muscle it bends medially and pierces the buccal fat pad and then the buccinators muscle. It
terminates in the vestibule of the mouth opposite of the 2nd maxillary molar. You can feel the duct with
your finger if you clench your jaw.
f. Sometimes there is an accessory parotid gland. A portion is detached from the gland- the facial process
of the gland and it is called an accessory parotid gland lying just superior to the parotid duct.
g. There is also a glenoid process of the gland. It sticks up behind the tempromandibular joint, but in front
of the external auditory meatus.
h. Parotid ducts's pass through the cheek is oblique which is important because it acts like a valve like
mechanism. When you blow against resistant, compression of the cheek compresses the duct and
prevents retrograde flow of air back into the parotid duct. People who persistently blow, some air will
get back into the parotid duct and cause swelling of the gland. If you get air back there it feels like a
sharp pain.
XV. [S21] Termination of the parotid duct
a. There is a parotid papilla there which some people can feel with their tongue
b. If you have an inflammation of the parotid gland that can spread along the duct to the papilla and it will
become reddened and inflamed. People may think they have a tooth problem.
c. You can also have bacteria from the oral cavity spreading retrogradedly through the duct to the gland.
d. You can have obstruction of the parotid duct that is called a calculus. It is a mineral deposit in the
parotid duct. The excretions of the gland can’t reach the oral cavity. It is extremely painful because the
parotid gland continues to secrete especially when you sit down to eat
e. One way to test this is to inject a radiopaque dye into the parotid papilla. Then take an x-ray. This is
called a saliogram. An x-ray of the salivary glands and its ducts.
f. If there is an obstruction then it will only flow up to that obstruction
XVI.
[S22,23] Nerve Supply to the Parotid gland
a. You might think that the facial nerve which penetrate the gland supplies the innervations, but it doesn’t.
The facial nerve has nothing to do with the innervations of the parotid gland. It just passes through it.
b. The glossopharyngeal (IX) nerve innervates the parotid gland
c. The parasympathetic fibers are shown in the diagram.
d. The presynaptic are solid blue lines and the postsynaptic are dashed.
e. Start in the medulla of the brain stem.
f. Presynaptic neuron cell bodies lie in the inferior salivatory nucleus. Axons go out CN 9.
Gross Anatomy 9:00-10:00
February 12, 2009
Dr. Zehren
Parotid Region
Scribe: Teresa Kilborn
Proof: Ashley Holladay
Page 4 of 6
g. In the jugular foramen it gives off a tiny branch called the tympanic nerve (won’t see in lab). It carries
the presynaptic parasympathetic fibers that are destined for the parotid gland. Tympanic refers to
middle ear and it enters the middle ear of the skull and breaks into the tympanic plexus then reunites to
forms the lesser petrosal nerve it leaves the skull through the foramen ovale and will synapse in the otic
ganglion in the infratemple region. Just below the foamen ovale that V3 and the lesser petrosal go
through.
h. The otic ganglion is one of the 4 major ganglions in the head. The others are: the ciliary, the
pterygopalatine, and the submandibular.
i. Synapse occurs in otic ganglion. From the otic ganglion to get to the parotid gland, the post synaptic
axons hitch a ride with the auriculotemporal nerve which is a branch of V3. The travel with it until it
reaches the parotid gland where it stimulates the gland to secrete. They are stimulatory.
j. There is a sympathetic innervations and the presynaptics lie in the lateral horn of the upper thoracic
cord, they synapse in the superior cervical ganglion, and get to the parotid gland by way of blood
vessels, in this case they run with the external carotid artery. They cause a decrease in salivation
(inhibitory).
XVII. [S24] Autonomic innervations of the parotid gland
a. This is a dissection. Medial view of jaw.
b. Mastoid process, Cranial Cavity, Middle ear cavity, Mandible, Maxilla, Medial pterygoid, Foramen ovale
with V3, Auriculotemporal nerve coming off of V3 and running behind TMJ.
c. You don’t see the entire pathway. Tympanic nerve and plexus are not shown. You do see the lesser
petrosal which emerges from the middle ear cavity from the tempanic plexus, leaves the middle ear and
after a short course inside the skull leaves through the foramen ovale, these are presynaptic
parasympathetics that originally ran with CN 9, synapse in the otic ganglion just medial V3, runs with the
auriculotemporal nerve to get to the parotid gland.
XVIII. [S25] Sensory Innervation to the Parotid gland
a. There is a sensory innervation to the gland for pain and general sensation.
b. Sensory fibers are carried in the auriculotemporal nerve.
c. You will see them in front of the ear running out of the gland. The auriculotemporal nerve is sensory,
cutaneous to the skin of the ear and temple. It also is sensory to the parotid gland and the TMJ.
d. It wraps around the TMJ.
e. Important because if you have parotid disease and pain it may be referred to the auricle, temple or
TMJ.
XIX.
[S26, 27] Frey’s syndrome (Gustatory sweating)
a. Interesting complication following parotid surgery or trauma to the gland called Frey's syndrome or
gustatory sweating
b. When they sit down to eat instead of salivating they begin to sweat in the region of the parotid gland
c. The explanation for this is that the penetration of the gland or when the damaged part is removed,
there is damage to two nerves: the great auricular nerve and the auriculotemporal nerve.
d. The great auricular nerve is the sensory nerve to the skin over the parotid gland coming from the
cervical plexus.
e. The auriculotemporal nerve is damaged, the one that sends parasympathetic fibers into the gland
f. After the gland has been removed or there is trauma, the parasympathetic fibers of the
auriculotemporal nerve in the gland begin to regenerate and instead of innervating the gland they
innervate with the great auricular nerve and end up innervating the sweat glands of the skin
g. Sweat glands have sympathetic innervations, but they are unusual that they receive cholinergic
innervations. (Most other post synaptic sympathetic receive norepinephrine . So the same
neurotransmitter is used and the post synaptic parasympathetic can stimulate and cause sweating
instead of salivation.
XX. [S28] Treatment and Prevention of Frey’s Syndrome
a. Different ways to deal with it
b. The most simple way is to apply topical anticholinergic cream but this is only temporary
Gross Anatomy 9:00-10:00
February 12, 2009
Dr. Zehren
Parotid Region
Scribe: Teresa Kilborn
Proof: Ashley Holladay
Page 5 of 6
c. Botox has been used which is a neurotoxin that will affect the stimulation of the sweat glands. But it can
be painful and it has other adverse side effects such as muscle weakness in the region of the lips
because it effects the NMJ as well
d. Surgical options include introducing a tissue flap or barrier like using a piece of fascia from the thigh, a
fasciolata. Putting the graph over the parotid bed , acting as a physical barrier so that the nerves cannot
innervate, but not always effective unless it has complete coverage
XXI.
[S29] Tympanic neurectomy (middle ear)
a. more extreme way to deal with it.
b. It involves cutting out a nerve. The idea is to interrupt the parasympathetic pathway to the gland.
c. Going into the middle ear. This is the tympanic cavity. Lateral view. Mastoid process. Ear drum has
been removed. On the medial wall is the tympanic nerve plexus. These are parasympathetic fibers
that are going to ultimately supply the parotid gland.
d. Surgeon goes in and destroys the tympanic nerve plexus and the nerve
e. Cases where regeneration has still occurred
XXII.
[S30] SCM flap rotated onto the deep lobe of the parotid gland
a. Sometimes use tissue flaps from adjacent tissue or muscle
b. This is the SCM, they cut a portion of the muscle and rotate it over the parotid gland, the deep portion
of the gland is still intact. You can see the facial nerve. Suture it to the zygomatic arch
c. Advantage- you are doing it at the time of the surgery (with removal of gland) and you are using a tissue
that is a part of your body
d. Also it helps to fill up the large space for cosmetic reasons
e. One way is to use the SCM
f. You can only do it if there is a rich blood supply to the muscle which the SCM has a rich bloodsupply
because 3 arteries supply this muscle- the occipital artery, the superior thyroid artery, and the
transverse cervical artery.
g. When you do this flap you have to be sure that the tissue you are graphing has good blood supply
otherwise it will become necrotic.
h. Risk is damage to the 11th cranial nerve
i. Sometimes a flap from the temporalis muscle and bring it over the zygomatic arch
XXIII. [S31, 32, 33, 34] Blood supply and Lympatic Drainage of the Parotid Gland
a. The ECA and terminal branches supply arterial blood
b. Retromandibular vein is the venous drainage
c. The lymphatic drainage is parotid lymph nodes located on and in the gland and from there the lymph
get to the deep cervical chain along the jugular.
SQ: Does the auriculotemporal nerve split into the superficial temporal branches? The auriculotemporal
nerve gives off branches to the ear and the temple. He wasn’t sure what she was talking about, but you don’t need
to worry about the auriculotemporal branches if they are named.
XXIV. [S36] Pop Quiz
a. What is A? Ramus of the mandible.
b. B- medial pterygoid muscle on the medial side of the ramus. On the lateral side of the ramus is the
masseter muscle.
c. C- posterior belly of the diagastric
d. Carotid sheath around D
e. D- Vagus nerve
f. Within it are the internal jugular vein and internal carotid artery. Common carotid divides on the upper
border of the larynx-C4.
g. E-the ECA
h. Retromandibular vein is to the right of E.
i. Tiny vessels between a and b are the inferior alveolar nerve, artery, and vein.
Other announcements:
Gross Anatomy 9:00-10:00
February 12, 2009
Dr. Zehren
Parotid Region
Scribe: Teresa Kilborn
Proof: Ashley Holladay
Page 6 of 6
Lab closes at one. Test tomorrow will be in two groups. The same groups that were assigned for today. Group A- 8-10
and Group B 10-12. The test should take about an hour and then they will come and answer questions. 50 tags. Be
there on time. You’ll grade your own test from the posted answers.
[end 42:21]