PBL 3 - Facial Anatomy

Question 1

Describe the blood supply of the face.

Answer 1

EXTERNAL CAROTID ARTERY:

1. Facial artery
   a. Superior labial branch
   b. Inferior labial branch
   c. Lateral nasal branch
   d. Angular artery (termination)
2. Superficial temporal artery
   a. Transverse facial artery
3. Maxillary artery
   a. Infra-orbital artery
   b. Buccal artery
   c. Mental artery

INTERNAL CAROTID ARTERY:

1. Ophthalmic artery
   a. Zygomaticofacial artery
   b. Dorsal nasal artery

Question 2

Draw a diagram of the facial anatomy, including the parotid gland, blood supply, venous drainage and the facial nerve.

Answer 2

See Stewart McDonald’s diagram.

Question 3

What is the venous drainage of the face?

Answer 3

INTERNAL JUGULAR VEIN

1. Facial vein
   a. Supratrochlear vein
   b. Supraorbital vein
2. Superficial temporal vein
   a. Transverse facial vein

INTRACRANIAL VENOUS CONNECTIONS

1. Ophthalmic veins
2. Infra-orbital foramen
3. Deep facial vein
4. Pteryoid plexus of veins

NOTE: all of these deep veins have connections to the cavernous sinus
NOTE: veins also have no valves, making this a likely route of infection

Question 4

What is the lymphatic drainage of the face?

Answer 4

1. Submental nodes
2. Submandibular nodes
3. Pre-auricular nodes

Question 5

Where does the parotid duct enter the mouth?

Answer 5

Near the 2nd upper molar tooth

Question 6

How much of the total saliva does each salivary gland produce?

Answer 6

Parotid - 20%
Submandibular - 65-70%
Sublingual - 5%

Question 7

What is the sensory innervation of the face?

Answer 7

Trigeminal nerve (CN 5)

a. Ophthalmic nerve (V1) - superior orbital fissure
b. Maxillary nerve (V2) - foramen rotundum
c. Mandibular nerve (V3) - foramen ovale

Question 8

What is the motor innervation of the face?

Answer 8

Facial nerve (CN 7)

Question 9

Describe how the function of the trigeminal nerve (CN 5) is tested.

Answer 9

1. Use a bit of cotton wool to test sensation in each of the 3 branches
2. Use a blunt pin to test sensation in each of the 3 branches
3. Test the corneal reflex by lightly touching the cornea with a wisp of cotton wool
   a. Patient should blink
4. Test the motor supply of the masseter m. and temporal m.
   a. Place hands over the muscles and ask patient to clench their teeth
5. Test the jaw jerk reflex
   a. Jaw should protrude slightly

Question 10

Describe how the function of the facial nerve (CN 7) is tested.

Answer 10

1. Ask patient to raise eyebrows/crease forehead
2. Ask patient to close their eyes and keep them closed while you try to (gently) open them
3. Ask patient to puff out their cheeks
4. Ask patient to bare their teeth

Question 11

Draw and label the muscles of facial expression.

Answer 11

See Stewart McDonald’s diagram (NOTE: there should be 15 muscles labelled (including the modiolus)).

Question 12

List the consequences of damage to the salivary glands.

Answer 12

1. Facial nerve damage
2. Intense pain on salivation/eating
3. Dry mouth
4. Sialocoeles (cysts filled with mucoid saliva in the soft tissue around the parotid gland - NOTE: may rupture to become a fistula)
5. Fistulas (communication between the skin and the parotid gland/duct that allows external drainage of saliva through the skin

Question 13

Describe violence reduction measures in Scotland.

Answer 13

Violence Reduction Unit

Medics Against Violence

AVDR training for other professionals

Question 14

Draw a diagram of the salivary ducts underneath the tongue.

Answer 14

See lab drawing for “Tongue” week

Question 15

Where does the submandibular duct enter the mouth?

Answer 15

Sublingual papillae