Exam 4 Nasal Cavity and PPF

Question 1

The Nose

• What forms the cartilaginous skeleton?
• What forms the bony skeleton?
• What makes up the bony portion of the nasal septum?
• What makes up the cartilaginous portion of the nasal septum?

Answer 1

• Cartilagionus skeleton made up by 2 lateral nasal cartilages and 2 greater alar cartilages
• Bony skeleton made up by two nasal bones, frontal processes of maxillae, and nasal part of frontal bones.
• Bony portion of nasal septum formed by: Perpindicular plate of ethmoid and vomer bones
• Cartilaginous portion formed by septal cartilage

Question 2

Nasal Cavity

• What is the nasal vestibule?
• What are the bony boundaries of the nasal cavity?
  
  • Superior wall
  • Inferior wall
  • Medial wall
  • Lateral wall
• What is the respiratory area of the nasal cavity?
• What is the olfactory area of the nasal cavity?

Answer 2

• Nasal vestibule: Initial space between nares and nasal septum (hairy)
• Bony boundaries:
  
  • Superior wall: Frontal, nasal, ethmoid, sphenoid bones
    
    • Perforated by cribiform plate of ethmoid bone
  • Inferior wall: Palatine process of maxilla bone and horizontal plate of palatine bone (forms hard palate)
  • Medial wall: Nasal septum
  • Lateral wall: Maxilla, palatine, and sphenoid bones
    
    • Superimposed by lacrimal, ethmoid, and inferior nasal conchae bones
• Respitory area: Lower 2/3 of nasal mucosa
• Olfactory area: Upper 1/3 of nasal mucosa

Question 3

Nasal conchae

• What bone does each conchae arise from?
• What spaces are between each conchae?
• What openings/features are found in each conchae?

Answer 3

• Superior and middle conchae: Part of ethmoid bone
• Inferior conchae: Separate bone
• Spaces (Meatuses)
  
  • Inferior meatus: Inferior to inferior conchae
    
    • Nasolacrimal gland opens here
  • Middle meatus: Inferior to middle conchae
    
    • Semilunar Hiatus: Crescent-shaped opening
    • Ethmoidal Bulla: Bulge in middle meatus posterosuperior to semilunar hiatus
    • Uncinate Process: Curved projection of ethmoid bone in middle meatus. Anteroinferior to semilunar hiatus
  • Superior meatus: Inferior to superior conchae
  • Sphenoethmoidal recess: Space superior to superior chonchae and inferior to superior wall.

Question 4

Blood Supply of Nasal Cavity

• What are the arteries?
• Where do they branch off of?
• What else do they supply (if applicable)?

Answer 4

• Sphenopalatine artery: Terminal branch of maxillary artery
  
  • Gives off posterior lateral nasal branches and posterior septal branches.
  • Largest blood supply to nasal cavity
• Posterior and anterior ethmoidal arteries: Branches of ophthalmic artery
• Greater palatine artery: Branch of maxillary artery
  
  • Supplies hard palate
• Lateral nasal artery: Branch of facial artery
• Superior labial artery: Branch of facial artery

Question 5

Nerves of Nasal Cavity

• What are they?
• What is their function?

Answer 5

• Olfactory nerves (CN I): Sense of smell
• Ophthalmic nerve (CN V1): Sensory information from anterosuperior portions of nasal cavity via anterior and posterior ethmoidal nerves
• Maxillary nerve (CN V3): Sensory information from septum via nasopalatine nerve and lateral wall via greater palatine nerve and posterior nasal nerve

Question 6

Sphenoid sinus

• Where is it located?
• What does it drain into?
• What is its innervation?
• What is its blood supply?

Answer 6

• Located in sphenoid bone
• Drains into sphenoethmoidal recess above superior nasal conchae
• Innervation: Posterior ethmoidal nerve (CN V1)
• Blood Supply: Posterior ethmoidal artery (off ophthalmic artery)

Question 7

Frontal Sinus

• Where is it located?
• Where does it drain?
• What is its innervation?
• What is its blood supply?

Answer 7

• Located between outer and inner layers of frontal bone
• Drains via frontonasal duct into ethmoidal infundibulum
  
  • Then drains into anterosuperior portion of semilunar hiatus of middle nasal meatus.
• Innervation: Supraorbital nerve (CN V1)
• Blood supply: Supraorbital artery (off ophthalmic artery)

Question 8

Maxillary Sinus

• Where is it located? (Boundaries)
• Where does it drain into?
• What is its innervation?
• What is its blood supply?

Answer 8

• Boundaries:
  
  • Roof: Floor of orbit
  • Floor: Alveolar part of maxillae
  • Medial walls: Border nasal cavity
• Drains into posterior end of semilunar hiatus of middle nasal meatus.
• Innervation: Anterior, middle, and posterior superior alveolar nerves (CN V2)
• Blood supply: Superior alveolar branches of maxillary artery

Largest of nasal sinuses.

Question 9

Ethmoidal Sinuses (Air cells)

• Where are they located?
• Where do they drain?
• What is their innervation?

Answer 9

• Several cavities located in ethmoid bone between nasal cavity and orbit
• Drainage:
  
  • Anterior ethmoidal cell: Ethmoidal infundibulum into semilunar hiatus of middle nasal meatus.
  • Middle ethmoidal cell: Drains directly into middle meatus via ethmoidal bulla
  • Posterior ethmoidal cell: Drains directly into superior meatus.

Question 10

Boundaries and Communications of Pterygopalatine Fossa

• Anterior
• Posterior
• Lateral
• Medial
• Superior
• Inferior

Answer 10

• Anterior: Posterior border of maxilla
• Posterior: Pterygoid process of sphenoid bone
  
  • Communications: Pterygoid canal, foramen rotundum, pharyngeal canal
• Lateral: Infratemporal fossa
  
  • Communications: Pterygomaxillary fissure
• Medial: Perpindicular plate of palatine bone, nasal cavity
  
  • Communications: Sphenopalatine foramen
• Superior: Greater wing of sphenoid bone
  
  • Communication: Inferior orbital fissure and orbit
• Inferior: : Pyramidal process of palatine bone
  
  • Communications: Palatine canal, greater &lesser palatine foramina

Question 11

Contents of Pterygopalatine Fossa

Answer 11

• 3rd part of maxillary artery
• Nerve of pterygoid canal
  
  • Formed by greater petrosal and deep petrosal nerves
• Maxillary nerve (CN V2) and its branches
• Pterygopalatine ganglion (parasympathetic ganglion for CN VII)

Question 12

Branches of Maxillary Nerve (CN V2)

• What are they?
• What do they supply?
• What openings do they pass through?

Answer 12

• Greater palatine nerve: Innervates palatal mucosa and palatal (lingual) gingiva posterior to maxillary canines
  
  • Passes through greater palatine foramen
• Lesser palatine nerve: Innervates mucous membranes and glands of soft palate, uvula, and palatine tonsil
  
  • Passes through lesser palatine foramen
• Nasopalatine nerve (long sphenopalatine nerve): Innervates nasal mucosa of septum and palatal mucosa of anterior hard palate
  
  • Exits PPF via sphenopalatine foramen
  • Enters hard palate via incisive foramen
• Posterolateral nasal branches (short sphenopalatine nerve): Innervates mucous membrane of lateral wall of nasal cavity
  
  • Exits PPF via sphenopalatine foramen
• Pharyngeal nerve: Innervates nasopharynx and sphenoidal sinus
  
  • Exits PPF via pharyngeal canal
• Zygomatic nerve: Exits PPF via inferior orbital fissure
  
  • Zygomaticofacial nerve: Innervates prominence of cheek
  • Zygomaticotemporal nerve: Innervates skin of anterior temple region
• Posterior superior alveolar nerve: Innervates most of maxillary molars and maxillary sinus, and buccal gingiva (via gingival branches)
  
  • Exits PPF pterygomaxillary fissure
  • Enters maxillary sinus via posterior superior
• Infraorbital nerve: Exits PPF via infraorbital canal
  
  • Middle superior alveolar nerve: Innervates maxillary premolars, maxillary sinus, buccal gingiva
  • Anterior superior alveolar nerve: Innervates maxillary sinus, maxillary canines, and maxillary incisors

Question 13

Pathway of parasympathetics from CN VII to lacrimal gland

Answer 13

• Cell bodies arise in superior salivary nucleus
• Parasympathetics travel within CN VII
• Branch off CN VII by geniculate ganglion and travels within Greater Petrosal Nerve
• Passes through petrous temporal bone via hiatus of facial canal
• Enters pterygoid canal via foramen lacerum
• Joins deep petrosal nerve to become nerve of pterygoid canal
• Preganglionic parasympathetics synapse in pterygopalatine ganglion
• Postganglionic parasympathetics hitch a ride on zygomaticotemporal nerve of CN V2 (maxillary nerve)
• Zygomaticotemporal nerve gives connecting branch to lacrimal nerve of CN V1 (ophthalmic nerve) to supply parasympathetic fibers to lacrimal gland

Question 14

Pathway of Sympathetic Fibers of Maxillary Nerve (CN V2)

Answer 14

• Deep petrosal nerve comes off internal carotid plexus
• Joins greater petrosal nerve to form nerve of pterygoid plexus
• Passes through pterygopalatine ganglion without synapsing
• Joins branches of maxillary nerve (CN V2)

Question 15

Arteries in Pterygopalatine Fossa

• What are they?
• What do they supply?
• What openings do they pass through?

Answer 15

• Descending palatine artery: Travels through palatine canal. Branches into:
  
  • Greater palatine artery: Supplies mucosa of hard palate
    
    • Exits palatine canal via greater palatine foramen
  • Lesser palatine artery: Supplies soft palate and palatine tonsil
    
    • Exits palatine canal via lesser OR greater palatine foramen
• Sphenopalatine artery: Exits PPF via sphenopalatine foramen. Branches into:
  
  • Posterolateral nasal branches: Supplies lateral wall of nasal cavity, portions of maxillary , ethmoidal, and sphenoidal sinuses
  • Posterior septal branches: Supplies nasal septum and hard palate (via nasopalatine artery which exits via incisive canal)
• Artery of pterygoid canal: Supplies superior pharynx, auditory tube, and middle ear
  
  • Exits PPF via pterygoid canal
• Posterior superior alveolar artery: Supplies molar and premolar teeth, maxillary sinus, and buccal gingiva
  
  • Exits PPF via posterior superior alveolar foramina
• Infraorbital artery: Supplies lower eye structures. Gives off anterior superior alveolar artery.
  
  • Exits PPF via infraorbital fissure -> infraorbital groove -> infraorbital canal -> infraorbital foramen