Face and Parotid

Question 1

What are the 5 layers of the scalp?

Answer 1

S-Skin
C-Connective Tissue 
A-Aponeurosis (from frontalis, occipitalis, and temporalis) 
L-Loose areolar tissue
P-Pericranium

Question 2

What are emissary veins and what is their clinical relevance?

Answer 2

Emissary veins connect the dural venous sinuses with veins outside the cranium. Although they are valveless, blood is usually away from the brain. However, in rare circumstances bacteria from a scalp infection can be transmitted to the dural sinuses via the emissary veins.

Question 3

How would you test each of the divisions of the trigeminal nerve?

Answer 3

In order to test the function of the divisions of the trigeminal nerve, you brush lightly over the skin of the forehead (V1), the skin of the cheek (V2), and the skin over the jaw (V3) on both sides of the face.

Question 4

What are the five branches of the facial nerve (CN VII)? What is the function of these facial n.
branches?

Answer 4

Temporal: Supplies the temporal region including Auricularis superior and anterior, occipitofrontalis, and orbicularis oculi.
Zygomatic: Supplies inferior part of orbicularis oculi
Buccal: Supplies buccinator m.
Marginal Mandibular: Supplies muscles of the lower lip and chin.
Cervical: supplies platysma

Question 5

What muscles are supplied with motor innervation just after CN VII exits the skull?

Answer 5

The auricular muscles are supplied right after CN VII exits the skull. In addition, the posterior belly of the digastric m. and stylohyoid m.

Question 6

Which branch of the facial nerve would be responsible for innervating each of the two sphincter
mm.?

Answer 6

Orbicularis Oris: Buccal branch of the facial nerve.

Orbicularis Oculi: Zygomatic and Temporal branches of the facial nerve.

Question 7

What function does the platysma play?

Answer 7

The platysma tenses the skin over the neck and lower face.

Question 8

What is the specific function of the buccinator?

Answer 8

The buccinator muscles presses and tenses the cheek for chewing, blowing, or whistling etc.

Question 9

What is the function of the frontalis muscle?

Answer 9

The frontalis muscles elevates eyebrows and wrinkles forehead. (surprise)

Question 10

Where does cutaneous sensory innervation above the frontalis m. arise from?

Answer 10

The greater occipital nerve, a branch of the cervical plexus.

Question 11

Trace the origin and course of the facial artery and facial vein. What are the branches of each? How
can infection track from the face to the cranial cavity?

Answer 11

Facial artery: arises from ECA just above the superior border of the hyoid bone then ascends deep to the submandibular gland, winds around the inferior edge of the mandible and enters the face. Its branches include: 
CERVICAL
-Ascending palatine a. 
-Tonsillar a. 
-Glandular a.
-Submental a. 
SUPERFICIAL FACIAL
-Inferior Labial a. 
-Superior Labial a. 
-Lateral Nasal a. 
-Angular a. 

Facial Vein: Terminates in internal jugular vein and communicates with the pterygoid plexus and the cavernous sinus. It receives drainage from the angular, nasal, and labial veins. Its branches include:

• Anterior Branch: receives facial vein
• Posterior Branch: Joins posterior auricular v. to form external jugular vein which drains into the subclavian.

Question 12

How is the retromandibular vein formed? Into what vessels does it drain?

Answer 12

The retromandibular vein is formed by the union of the superficial temporal vein and the maxillary vein.

Question 13

Which vessels supply arterial blood to the scalp?

Answer 13

5 branches total provide arterial supply to scalp:

• 3 from external carotids: Occipital aa, Posterior Auricular aa, & superficial temporal aa
• 2 from internal carotids: Supratrochlear aa & Supra-orbital aa

Question 14

What nerves provide sensory innervation to the scalp?

Answer 14

Innervation of scalp is divided by location of auricles of external ear:

• anterior to auricles, inn = V1, V2, and V3
• Posterior to auricles, inn= Spinal cutaneous nerves (C2 and C3)

Question 15

What are the three divisions of the trigeminal nerve? Be able to indicate their pattern of sensory distribution on a diagram.

Answer 15

V1 = Opthalmic - forehead to lateral corner of eyes (going right under eyes to top of nose)
V2 = Maxillary - between lateral corners of eyes and corners of mouth (cheeks and upper jaw)
V3 = Mandibular - mandible (lower jaw); makes "smiley face" shape going up from mouth in front of ear

Question 16

What are the major terminal branches of V1? Through what passage/foramen do these branches access the face?

Answer 16

(4) terminal branches of V1 (Opthalmic)
- Supraorbital (from Frontal n) –> Supraorbital Foramen
- Supratrochlear (from Frontal n)–> Supratrochlear foramen/notch
- Infratrochlear (from Nasociliary n)–> follows medial wall of orbit, passing inferior to Trochlea
- External Nasal n (term. branch of Ant Ethmoidal n)–> passes between nasal bone and lateral nasal cartilage

Question 17

What are the major terminal branches of V2? Through what passage/foramen do these branches access the face?

Answer 17

(3) terminal branches of V2 (Maxillary):
- Infraorbital (directly from V2) –> Infraorbital foramen
- Zygomaticofacial (from Zygomatic n)–> Zygomaticofacial foramen
- Zygomaticotemporal (also from Zygomatic n) –> passes to temporal fossa via Zygomaticotemporal Canal in zygomatic bone

Question 18

What are the major terminal branches of V3? Through what passage/foramen do these branches access the face?

Answer 18

(3) terminal branches of V3 (Mandibular):
- Auriculotemporal –> passes posteriorly deep to ramus of mandible and the superior part of Parotid gland, emerging posterior to TMJ
- (Long) Buccal n –> passes between two parts of lateral pterygoid m, emerging anterior from ramus of mandible to unite w/ buccal branches of CN VII
- Mental n –> Mental foramen

Question 19

What is trigeminal neuralgia?

Answer 19

a.k.a. Tic douloureax or Fothergill Disease. When damage to Trigeminal N causes abnormal, “lightning-like” jabs of pain all along CN V. These paroxysms (sudden, sharp pain) can last up to 15 min and be brought on by touching the face, brushing teeth, chewing, etc.

Question 20

Through what bony opening does the facial nerve exit the cranial cavity? The base of the skull?

Answer 20

ALL fibers of CN VII exit cranial cavity via Internal acoustic meatus, entering the temporal bone. Then:
Somatic motor and somatic sensory fibers of CN VII take a sharp turn at the facial canal of the temporal bone to exit the skull at the Sylomastoid foramen

Question 21

What are the two major sphincter muscles of facial expression?

Answer 21

Orbicularis oculi and Orbicularis oris

Question 22

List the muscles associated with lifting and depressing the corners of the mouth.

Answer 22

(6) of the Buccolabial mm that insert directly and act on the corners of the mouth:
- Zygomaticus major: smile
- Zygomaticus minor: “Elvis muscle” & smile
- Levator anguli oris: disgust
- Risorius: false smile (i.e. close-lipped smile)
- Depressor anguli oris: frown
- Buccinator: whistle and chewing

Question 23

State the specific branch of the facial nerve that innervates the platysma.

Answer 23

Cervical branch of CN VII

[the “C” in Ten Zebras Bought my Car]

Question 24

State the specific innervation of the Buccinator.

Answer 24

Buccal branch of CN VII

[the “B” in Ten Zebras Bought My Car]

Question 25

State the specific innervation of the Frontalis muscle.

Answer 25

Temporal branch of CN VII.

This branch also innervates the auricularis superior, auricularis anterior, and the superior part of Orbicularis Oculi.

Question 26

What is Bell’s Palsy? How does an individual affected with Bell’s Palsy appear?

Answer 26

A unilateral paralysis of facial muscles due to a lesion of the Facial nerve. Clinical presentation = facial distortion, including sagging corner of mouth; inability to smile/whistle/blow; drooping of upper eyelid; and inability to close/blink eye.

Question 27

What is cavernous sinus thrombosis?

Answer 27

Clotting in the cavernous sinus, usually resulting from infections in the “danger triangle.” Thrombophlebitis (clotting and inflammation of vessel wall) of the facial vein can lead to thrombophlebitis of the cavernous sinus. This may affect function of Abducens N (traversing the sinus), as well as the nn imbedded in lateral wall of sinus. Septic cavernous sinus thrombosis often results in development of Acute Meningitis.

Question 28

What is the function of the parotid gland?

Answer 28

The parotid gland produces saliva and empties it via the parotid duct (Stenson’s duct), which exits the anterior aspect of the gland below zygomatic arch and travels superficial to masseter m.

Question 29

Trace the parasympathetic pathway for the parotid gland from CNS to target.

Answer 29

Parasympathetic inn of parotid gland comes from the Lesser Petrosal N, a branch of CN IX (Glossopharyngeal):

• Preganglionic parasympathetic fibers in lesser petrosal n synapse in Otic ganglion
• Postganglionics then “hitch a ride” on the Auriculotemporal n (CN V3) to parotid gland

Question 30

Trace the sympathetic pathway for the parotid gland from CNS to target.

Answer 30

Preganglionic sympathetic fibers synapse in Superior Cervical Ganglion (like all sympathetic inn of head!)
Postganglionics then travel from superior cervical ganglion to the parotid gland via the Carotid Plexus by branches of external carotid artery