Nasal Cavity And Paranasal Air Sinuses Flashcards
What are the primary functions of the nasal cavity?
Warming, humidifying, and filtering inspired air.
Olfaction (detecting airborne odorant molecules via olfactory epithelium).
Name the three nasal conchae and their anatomical features.
Superior concha (projection of ethmoid bone).
Middle concha (projection of ethmoid bone).
Inferior concha (longest; separate bone).
List the four paranasal sinuses and their drainage pathways.
Maxillary sinus → Middle meatus (via semilunar hiatus).
Frontal sinus → Middle meatus (via frontonasal duct).
Ethmoidal sinuses → Anterior/middle: middle meatus; Posterior: superior meatus.
Sphenoidal sinus → Sphenoethmoidal recess.
What is Kiesselbach’s area, and why is it clinically significant?
A vascular plexus in the anteroinferior nasal septum where four arteries anastomose.
Significance: Common site of epistaxis (nosebleeds) due to trauma or dryness.
Why is the maxillary sinus prone to infection?
Due to poor drainage—its ostium is located high on the medial wall, making mucus drainage dependent on ciliary action.
What is the “dangerous area of the face,” and why is it dangerous?
Lower external nose and upper lip.
Risk: Infections can spread to the cavernous sinus via valveless veins (e.g., facial vein → ophthalmic vein).
How can maxillary sinusitis present clinically?
Toothache (shared maxillary nerve innervation).
Pain over the cheek.
Purulent nasal discharge.
What structures are at risk during sphenoid sinus surgery?
Pituitary gland.
Optic nerve.
Internal carotid artery.
What are the functions of the paranasal sinuses?
Lighten the skull.
Resonate speech.
Produce mucus for nasal cavity.
Which sinus is accessed during transsphenoidal pituitary surgery?
Sphenoidal sinus (provides a route to the pituitary gland).
What is the clinical term for inflammation of multiple sinuses?
Parasinusitis
Which artery supplies Little’s area?
Anastomosis of:
Anterior ethmoidal (ophthalmic).
Sphenopalatine (maxillary).
Greater palatine (maxillary).
Septal branch of superior labial (facial).
What is the sphenoethmoidal recess, and which sinus drains here?
A small space posterior to the superior concha.
Drains: Sphenoidal sinus.
What are the boundaries of the nasal cavity?
Roof: Cribriform plate of ethmoid, nasal bones, sphenoid.
Floor: Palatine process of maxilla, horizontal plate of palatine bone.
Lateral wall: Conchae, meatuses, maxilla, ethmoid, palatine bones.
Medial wall: Nasal septum (vomer, perpendicular plate of ethmoid, septal cartilage).
How does the nasolacrimal duct communicate with the nasal cavity?
Opens into the inferior meatus.
Drains tears from the lacrimal sac.
Why is the olfactory area of the nose considered dangerous?
Infections can spread to meninges via olfactory nerve sheaths or to dural sinuses (e.g., cavernous/superior sagittal sinus) through valveless veins.
What bones and cartilages support the external nose?
Nasal bones, frontal process of maxilla, nasal part of frontal bone.
Inferior: Lateral nasal, septal, and alar cartilages.
What is the clinical significance of the relationship between maxillary sinuses and teeth?
Tooth roots (especially molars) may protrude into the sinus.
Risk: Tooth extraction → oro-antral fistula; sinusitis → referred toothache.
What is the difference between anterior and posterior ethmoidal sinuses in drainage?
Anterior/Middle ethmoidal: Middle meatus (via semilunar hiatus/bulla).
Posterior ethmoidal: Superior meatus.
Which arteries supply the nasal cavity?
Anterior/Posterior Ethmoidal (ophthalmic artery).
Sphenopalatine and Greater Palatine (maxillary artery).
Septal branch of Superior Labial (facial artery
What is the function of respiratory mucosa in the nasal cavity?
Moistens inspired air.
Traps particles via mucus and ciliary action (mucociliary clearance).
What are the clinical implications of a deviated nasal septum?
Nasal obstruction → chronic sinusitis, sleep apnea, or epistaxis.
May complicate rhinoplasty or nasal surgery
Which nerve innervates the mucosa of the maxillary sinus?
Maxillary nerve (V2) (also explains referred pain to teeth).
What is the anatomical route for transsphenoidal pituitary surgery?
Nasal cavity → sphenoethmoidal recess → sphenoid sinus → pituitary fossa.
Why might frontal sinusitis cause pain above the eyes?
Inflammation of mucosa in the frontal sinus (located behind eyebrows) irritates local nerves.
What is the term for the anterior opening of the nasal cavity?
Nostril (naris). Bounded laterally by ala and medially by septum.
How do the paranasal sinuses develop embryologically?
As outgrowths from the nasal cavity (pneumatized bones), hence their drainage into the nose.
What is the role of the semilunar hiatus?
Drainage pathway for maxillary sinus, frontal sinus, and anterior ethmoidal sinuses into the middle meatus.
Which sinus is most likely to cause orbital cellulitis if infected?
Ethmoidal sinuses (due to proximity to the orbit).
