Anatomy - Nose And Nasal Cavity Flashcards
What are the functions of the nose and nasal cavity?
Sense of smell A route for inspired air Filters inspired air - trapping particles in nasal hair or mucous Moistens and warms inspired air Resonating chamber for speech
When the nose is blocked due to a cold, why does the mouth get dry?
Because on of the functions of the nose is to moisten and warm inspired air
The external nose is made up of…
Cartilage and bone
Where in the external nose does inspired air initially enter?
The vestibule
What bones make up the perimeter of the nose?
Nasal bone
Part of maxilla
Nasal bone is prominent on face, so susceptible to fracture. Why can it be hard to tell if displacement has occurred?
Swelling
Why should x ray not be done even if suspect a nasal fracture?
Will not change immediate management
Why does speed of airflow slow down as it enters the nasal cavity?
Greater cross sectional area
The whole of the nasal cavity is lined with mucous membrane, more specifically called…
Pseudostratified columnar ciliates epithelium
At the top of the nasal cavity there is an olfactory mucous membrane. This is where the ends of what nerve are found?
Olfactory nerve - perceive smell
What is the role of the respiratory mucous membrane?
Filter - mucous/cilia
Humidify - watery secretions
Warm air - rich blood supply
The nasal cavity receives drainage from…
Paranasal sinuses Nasolacrimal duct (this is why nose runs when you cry)
What is the medial wall of the nasal cavity?
Nasal septum - bony and cartilagenous part
Bony = perpendicular plate of ethmoid and vomer
What comprises the lateral wall of the nasal cavity?
Bony projections covered by respiratory mucosa - conchae
Superior
Middle
Inferior
What is the spaces between the conchae in the nasal cavity called?
Meatuses (there are 3)
Where paranasal sinuses and nasolacrimal duct drain into
What is the role of the conchae in the nasal cavity?
Create turbulence of air flow
Increase surface area of mucous membrane - can be filtered and warmed more
What makes the roof on the nasal cavity?
Frontal bone
Ethmoid - cribiform plate
Part of sphenoid
How can CSF pass into the nasal cavity?
Anterior cranial floor fracture that involves the cribiform plate
Which cranial nerve carries general sensation from the nasal cavity?
Trigeminal - mostly maxillary division, small part ophthalmic
Why is there a rich blood supply to nasal mucosa?
Allow for warming and humidification of inspired air
What is epistaxis?
Nose bleed
Arterial supply to the nasal cavity arises from branches of what arteries?
Ophthalmic artery
Maxillary artery
What branches of the ophthalmic artery supply the nasal cavity?
Posterior and anterior ethmoid
What branch of the maxillary artery supplies the nasal cavity?
Sphenopalatine artery
What is the ophthalmic artery a branch of?
Internal carotid artery
What is the maxillary artery a branch of?
External carotid artery
Where is the most common source of bleeding in epistaxis?
Kiesselbach’s area/plexus = area of arterial anastomoses
Is Kiesselbach’s are in the anterior or posterior nasal cavity?
Anterior
Veins from nasal cavity drain into…
Pterygoid venous plexus, cavernous sinus, facial vein
A small number of nose bleeds occur from what artery (more serious bleeding)?
Sphenopalatine artery
Why is bleeding from the sphenopalatine artery more difficult to treat?
At back of nasal cavity, so difficult to compress
What are paranasal sinuses?
Air filled spaces that are extensions of the nasal cavity
What are the paranasal sinuses lined with?
Respiratory mucosa - that are also ciliated and secrete mucous
How are the sinuses named?
According to bone they are in
Four pairs
What are the sinuses called?
Frontal
Maxillary
Ethmoid
Sphenoid
What is the role of the sinuses?
Help humidify and warm inspired air
Reduce weight of the skull
Where do sinuses drain into?
Nasal cavity via small channels called ostia into a meatus (mostly middle one)
Roots of the upper teeth can sometimes project into which sinus?
Maxillary
What are some important anatomical relations of the sinuses?
Nasal cavity
Orbit
Anterior cranial fossa
What innervates the frontal, ethmoid and sphenoid sinuses?
Ophthalmic division of trigeminal nerve
What innervates the maxillary sinus?
Maxillary division of trigeminal nerve
