Week 7 Nasal Cavity, Paranasal Sinuses, and pterygopalatine Fossa

Question 1

List the paranasal sinus openings and locations of the openings in the nasal cavity.

Answer 1

1. Superior meatus:
   - posterior ethmoids
2. middle meatus:
   - opening of frontal sinus
   - opening of maxillary sinus
   - ethmoid openings (superior and middle)
3. inferior meatus
   - nasolacrimal duct opening

Question 2

What are the 6 openings in and out of the pterygopalatine fossa? What structures go through these openings?

Answer 2

1. Foramen rotundum: V2
2. Pterygoid canal: greater petrosal nerve
3. greater palatine foramen: greater and lesser palatine nerves
4. Inferior orbital fissure: infraorbital nerve and artery
5. Pterygomaxillary fissure: maxillary artery
6. sphenopalatine foramen: sphenopalatine artery

Question 3

Describe the blood supply to the nasal cavity.

Answer 3

1. Three terminal branches of the maxillary artery
   a. Sphenopalatine artery: posterior 2/3 of nasal cavity
   b. infraorbital artery:
   c. descending palatine artery: runs along inferior surface of hard palate, supplies hard and soft palate
2. opthalmic artery branches (V1): anterior superior nasal cavity

Question 4

Where do nosebleeds predominantly occur?

Answer 4

• Kiesselbach’s area: anastmoses of arteries in anterior third of septum between branches of internal and external carotid arteries
• 10% of nosebleeds are posterior, rest are anterior

Question 5

What cell bodies are located in the Pterygopalatine ganglion?

Answer 5

-para/post

Question 6

Trace the pathway of the facial nerve innervation to the lacrimal gland, nasal and pal tine mucous glands.

Answer 6

1. Para/pre
   -facial nerve–>greater petrosal n.–>nerve of pterygoid canal–>pterygopalatine ganglion
   A. –>branches of V1/V2–>lacrimal nerve–>lacrimal gland
   B. –>greater palatine n. –>nasal and palatine mucosa

Question 7

What is the sensory innervation distribution of the nasal cavity?

Answer 7

1. Maxillary (V2) branches provides SS to posterior 2/3 of lateral and medial walls of nasal mucosa+hard/soft palate
   - greater palatine: hard palate
   - lesser palatine: soft palate
2. Ophthalmic (V1)-nasocilliary branches supplies anterior 1/3, lateral and medial wall
3. Roof of cavity has special sense from CN I

Question 8

Removal of a tumor in temporal lobes of brain requires removal of the dura and the two small nerves on the floor of the middle cranial fossa, leading to dry eye, dry nose and dry mouth. What are those two nerves?

Answer 8

Greater and lesser petrosal nerves