Nasal Cavities

Question 1

Describe the anatomy of the nasal cavity:

Answer 1

Roof - nasal, frontal, ethmoid, and sphenoid bones

Floor - hard palate (maxilla and palatine bones)

Medial wall - nasal septum (comprised of the vomer, perpendicular plate of the ethmoid, and septal cartilage)

Lateral wall - superior, middle and inferior conchae

Meatus - passage found inferior to each conchae
Sphenoethmoidal recess -uppermost passage

Question 2

Describe the anatomy of the paranasal sinus

Answer 2

4 paired mucosa-lined air spaces that drain to nasal cavity

Nasolacrimal duct projects into inferior meatus

Semi-lunar hiatus

Ethmoid bulla

lined with respiratory epithelium

Question 3

What are the 4 paranasal sinuses, their drainage location and nervous innervation ?

Answer 3

Sphenoid;
- sphenoethmoidal recess
- ophthalmic nerve and maxillary nerve

Ethmoid;
- superior meatus via ethmoidal bulla
- ophthalmic and maxillary nerve

Maxillary;
- middle meatus
- maxillary nerve

Frontal;
- middle meatus via front-nasal duct which passes through semi-lunar hiatus
- ophthalmic nerve

Question 4

Describe epistaxis and the arteries involved:

Answer 4

Nosebleeds as so vascular for warming air

Anterior and posterior ethmoidal arteries - coming from orbit and going to nose

Sphenopalatine artery - runs between sphenoid and palatine bones, supplies posterior septum

Greater palatine artery - come through palatine bone (greater palatine foramen), innervates near palate

Superior labial artery - from lower lip, supplies anterior part

Sphenopalatine, greater palatine, superior labial are direct & indirect branches of external carotid artery

Question 5

Where are nosebleeds most common ?

Answer 5

Little’s area/Kisselbach’s plexus = most common site for epistaxis due to dense blood supply

Question 6

What are the functions of the nasal cavity ?

Answer 6

Air filtration and humidification - Mucosa traps dust and warms the air.

Olfaction- The superior part contains the olfactory epithelium for smell detection.

Question 7

What are the functions of the paranasal sinus ?

Answer 7

Functions;
- lighten the weight of the skull
- voice resonance
- crumple zone in case of trauma