Nasal Cavity and Air Sinuses Flashcards
The external nose is made primarily of what?
cartilage
What are the different cartilages of the external nose?
two large lateral nasal cartilages and two greater alar wing cartilages
-also a number of smaller cartilages and soft tissue
What is bony portion of the nose referred to as?
the bridge of the nose
What comprises the bony portion of the nose?
two nasal bones on either side of the midline, a portion of frontal bone, and a portion of maxillary bones
What divides the nasal cavity into right and left?
nasal septum
How do the nasal cavities communicate anteriorly?
through the external nares (nostrils)
What marks the opening of the nasal cavity?
the external nares
What guards the opening of the nasal cavity?
coarse hairs in the external nares that keep out debris from the environment
How do the nasal cavities communicate posteriorly?
internal nares or choanae
Where are the internal nares located?
just before the nasopharynx, the portion of the pharynx closest to the nasal cavity
What makes up the medial wall of the nasal cavity (nasal septum)?
- vomer
- perpendicular plate of ethmoid bone
- septal cartilage
What is the roof of the nasal cavities?
- nasal bones
- frontal bone
- ethmoid bone
- sphenoid bone
The rood of the nasal cavities is perforated by what?
cribriform plate of the ethmoid bone through which the olfactory axons called filia olfactoria pass into the olfactory bulb
What lies above the roof of the nasal cavities?
the anterior cranial fossa
What makes up the floor of the nasal cavities?
- palatine process of the maxilla anteriorly
2. horizontal plate of the palatine bone posteriorly
The floor of the nasal cavities separates it from what cavity?
oral cavity
What makes up the lateral wall of the nasal cavities?
- frontal process of the maxilla
- palatine bone
- sphenoid bone
What structures are superimposed (laid over) the lateral wall of the nasal cavities?
lacrimal, ethmoid, and inferior nasal concha
What are nasal concha?
3 sea-shell shaped thin bony ridges that protrude out into the cavity in a gentle curve; superior, middle, inferior conchae
Which two nasal concha are associated with the ethmoid bone and which one is independent?
superior and middle, inferior is independent
What is a nasal meatus?
a space under each nasal concha; superior, inferior, and middle meatuses
What is the purpose of the meatuses?
each meatus is a site of drainage for one or more of the four paired paranasal air sinuses or the nasolacrimal duct
What are the four paired paranasal sinuses?
- frontal
- maxillary
- sphenoidal
- ethmoidal air cells (anterior, middle, and posterior groups)
What is the superior meatus a site of drainage for?
- posterior group of ethmoidal air cells
- sphenoidal sinus
How does the sphenoidal sinus and posterior group of ethmoid air cells drain into the superior meatus?
drain into the space above the superior concha, the sphenoethmoidal recess
What is the ethmodial bullae?
protrusion of the ethmoid bone
What lies underneath of the ethmoidal bullae?
a semi-circular groove called the hiatus semilunaris
What is the middle meatus a site of drainage for?
- frontal sinus
- maxillary sinus
- anterior ethmoidal air cells
- middle ethmoidal air cells
How does the frontal sinus drain into the middle meatus?
via the frontonasal duct in the hiatus semilunaris
How does the maxillary sinus drain into the middle meatus?
via the hiatus semilunaris
How do the anterior ethmoidal air cells drain into the middle meatus?
via the hiatus semilunaris
How does the middle ethmoidal air cells drain into the middle meatus?
empty onto the surface of the ethmoidal bulla
What drains into the inferior meatus?
nasolacrimal duct (tear duct, not a sinus)
The nasolacrimal duct is located where in the inferior meatus?
in the anterior region
What does the nasolacrimal duct do?
channels tears from the conjuctival sac (crying, allergies)
Why is the nasolacrimal duct often not visible in the nose?
due to swelling of the surrounding mucosa
What is the function of olfactory epithelium?
sense of smell
Where is the olfactory epithelium located?
in the uppermost region of the septum, lateral wall, and roof of the nasal cavity
What is the function of respiratory epithelium?
sweeping mucus and collected debris out of the nasal cavity and down the throat (contains mucus cells)
Where is the respiratory epithelium located?
the lower portion of the nasal cavity
What are olfactory receptor cells?
bipolar neurons within the olfactory epithelium
The axons of the bipolar neurons leave the olfactory epithelium how?
in groups that pass upward through the cribriform plate of the ethmoid bone as filia olfactoria (groups of about 20 axons)
the filia olfactoria are the _____ first cranial nerve, while the bulb inward represents a _____
true; tract
Where do filia olfactoria synpase?
in the overlying olfactory bulb, which then becomes the olfactory tract
What nerve is the most easily lesioned cranial nerve?
CN 1 (olfactory)
What is the most common reason for a lesion to CN 1?
damage from head trauma where the cranium may hit a windshield etc. and quickly rebound back, ripping the small filia olfactoria
What typically accompanies damage to CN 1?
dripping of CSF from the nose
The ethmoid bone contributes to a large portion of the boundaries of the nasal cavity through what structures?
roof: crista gali and cribriform plate
medial wall: perpendicular plate
lateral wall: superior concha and middle concha
What forms a good portion of the medial wall of the orbit?
ethmoid air cells
CN 1 provides what type of innervation to the nasal cavity?
smell, by exiting through the cribriform plate of the ethmoid bone
What nerves supply general sensation to the nasal cavity?
anterior ethmoidal nerve (V1), infraorbital nerve (V2), maxillary nerve (V2)
What are of the nasal cavity is supplied by the anterior ethmoidal nerve (V1)?
anterior and upper regions of the lateral and medial walls of the nasal cavity
-exits through SOF
What areas of the nasal cavity are supplied by the infraorbital nerve (V2)?
the skin of the vestibule
-exits through foramen rotundum
What areas of the nasal cavity are supplied by the maxillary nerve (V2)?
the lower and posterior regions are innervated via br. from the pterygopalatine ganglion that hangs just behind the shenopalatine foramen in the upper posterior aspect of the lateral wall of the nasal cavity
-exits through foramen rotundum
What nerve passes through the incisive foramen?
the nasopalatine nerve that supplies a portion of the mucosa lining the hard palate
The medial and lateral walls of the nasal cavity are supplied by what branches of the internal carotid artery?
internal carotid a.–>ophthalmic a.–> anterior and posterior ethmoid aa.
The medial and lateral walls of the nasal cavity are supplied by what branches of the external carotid a.?
external carotid a. –> facial a.–>superior labial a.
external carotid a.–>maxillary a.–>sphenopalatine a. and greater palatine a.
Rupture of what artery is the most common cause of nose bleeds?
the superior labial branches from the facial a. from the external carotid a.
