Anatomy/Physiology - Nose & Sinus Flashcards
(34 cards)
Functions of the nasal cavity?
- Warm and humidify inhaled air
- Immune barrier
- Smell
- Drainage and aeration of middle ear
- Drainage of paranasal sinuses and lacrimal duct
What is choanal atresia?
Congenital disorder where the back of the nasal passage (choana) is blocked
Problem as neonates are obligate nasal breathers
Describe the epithelium of the specialized nasal mucosal lining
- First 1/3 stratified squamous epithelium with nasal hairs
- Posterior 2/3 pseudo-stratified columnar epithelium with cilia & goblet cells
Function of the mucus produced by goblet cells in the nasal cavity?
- Trap pathogens
Which nerve is responsible for smell? Which bone does it travel through?
Olfactory nerve
Passes through the cribriform plate of the ethmoid bone
Functions of the Sinuses?
- Reservoir of warm, humid air
- Lighten skull
- Crumple zones (protection)
- vocal resonance
- Immune barrier
How much of the external nose is bony and how much is cartilaginous?
- 1/3 bony
- 2/3 cartilaginous
Name the sections of the external nasal area
- Columella
- Tip
- Supratip
- Dorsum
- Nasion
- Glabella
What forms the roof, walls and floor of the nasal cavity?
Roof - Cribriform plate (skull base)
Walls - Turbinates
Floor - Hard palate
What structures make up the nasal septum?
- Septal cartilage
- Vomer bone
- Perpendicular plate of ethmoid bone
Describe the quality of blood flow to the septal cartilage
Poor blood supply
Gets blood from mucosa overlying it
What is a septal haematoma?
Localized bleeding outside of vessels in the septal mucosa - creates barrier of stagnant blood between septal cartilage and mucosal blood supply
Usually associated with trauma
Possible consequences of septal haematoma?
- No new blood supply to cartilage
- Can lead to septal necrosis and perforation
Haematoma needs to be drained ASAP
What are the three turbinates called? What is a turbinate?
Function?
Superior, Middle, Inferior
Bony projections from the lateral wall of the nose
Increase the SA of the nose (humidification and warming)
What is located underneath the turbinates?
The corresponding meatus
What is the nasolacrimal duct?
- Drainage pathway for lacrimal secretions (tears)
- From lacrimal sac (next to eye) to inferior meatus of nasal cavity
(runny nose when crying)
What are the paranasal sinuses?
Air filled extensions of the respiratory part of the nasal cavity
Lined with respiratory epithelium, and all open back into the nasal cavity
Four pairs of paranasal sinuses?
- Frontal
- Maxillary
- Ethmoid air cells
- Sphenoid
(not sure if the sphenoid is paired?)
Where is the frontal sinus? Where does it drain to?
Pathway of drainage?
Frontal sinuses are behind eyebrows
Drain to the middle meatus
Drains via frontal recess, moves inferiorly, just lateral to middle turbinate
Where are the ethmoid air cells?
Two divisions of the ethmoid sinuses?
Honeycomb structure between the eyes
Anterior and posterior
What separates the anterior and posterior ethmoid sinuses?
The ground lamella
- the turn of the middle turbinate at the back of the nose, where it attaches to the lateral nasal wall
Where does the anterior ethmoid sinus drain to?
The posterior sinus?
Anterior - middle meatus
Posterior - superior meatus
If sinusitis spreads to the ethmoid air cells, how may the disease progress?
Infection may spread to the orbits because bone of the ethmoid sinuses separating it from the orbit is paper thin
Causes periorbital/orbital cellulitis - won’t improve until sinusitis is treated
Where does the sphenoid sinus drain to?
What neurovasculature is closely associated with the sphenoid sinus?
Drains into sphenoethmoidal recess (above superior turbinate)
Optic nerve runs above, internal carotids either side
