Anatomy & Physiology of Nose Flashcards
5 functions of the nose
Airway passage Immune barrier Smell Drainage and aeration of middle ear Paranasal sinuses + nasolacrimal duct drain into nose
What does the nose do to inspired air
Warms + humidifies it
Why is nasal airway important for newborns (esp first 6 weeks) + what is the term that describes this
Because they mainly breathe through nose at the start
Babies are OBLIGATE NASAL BREATHERS - necessity to breathe through nose opposed to mouth
What is choanal atresia (2)
Congenital disorder where nasal passages are blocked by bone or soft tissue
Baby goes blue when they can’t breathe
How is the nose an immune barrier (3)
It contains nasal hairs to trap large particles
Contains goblet cells which secrete mucous to trap pathogens
Mucous contains antibodies and lysozymes
Epithelial lining of nasal mucosa (2)
- anterior 1/3
- posterior 2/3
Anterior 1/3 lined by stratified squamous epithelium
Posterior 2/3 lined by pseudostratified ciliated columnar epithelium
What does the anterior 1/3 of the nose contain
Nasal hairs to trap large particles
What does the posterior 2/3 of the nose contain (3)
Cilia - to move mucous
Goblet cells - secrete mucous
Mucous - to trap pathogens
Is mucous secreted in the nose acidic or alkaline + what effect does this have on pathogens
Alkaline - unfavourable for bacteria
Layers that make up mucous in the nose
Thick gel layer on the bottom Thin sol (watery) layer on top
What does mucous secreted in the nose contain (3)
IgA
IgE (for allergies)
Lysozymes - break down bacteria
What nerve allows smell + how does it get to nose
Olfactory nerve (CN I) Passes through foramina in cribriform plate at the roof of the nose
How is the middle ear drained and aired out
Via the Eustachian tube - links middle ear to nasopharynx to allow pressure in middle ear to equalise with atmospheric pressure
Function of paranasal sinuses (3)
Reservoir of warm air
Lighten the skull - because air is light
Act as ‘crumple zones’ - absorb trauma to face and protects brain
Vocal resonance
Components of external nose (describe top 1/3 and lower 2/3 components)
Top 1/3 is BONY = made of 2 nasal bones + frontal processes of maxilla
Lower 2/3 is CARTILAGINOUS = nasal septum centrally, upper lateral cartilages, lower lateral cartilages
Which is easier to fix - broken nasal bone or cartilage
Bone because you can move it back into position before they heal whereas it’s not easy to unbend broken/bent cartilage
What forms the midline/roof/walls (lateral)/floor of internal nose
Midline - nasal septum
Roof - skull base/ cribriform plate
Walls - turbinates
Floor - hard palate
Components of the nasal septum (3)
2 bones
- vomer
- perpendicular plate of ethmoid
Septal cartilage
Where does septal cartilage get its blood supply
From the mucosa overlying it so if mucosa gets separated from cartilage during trauma e.g. then it loses its blood supply and can necrose
What are turbinates + name them
Bony structures covered in soft tissue that protrude from the lateral wall of the inner nose
Super/middle/inferior
Function of turbinates (2)
Increase surface area of nasal cavity so more air can be humidified + warmed
Disrupt fast laminar air flow, making it slow and turbulent so air can spend longer in nasal cavity to be humidified
What space is under each turbinate
A meatus
What is the nasolacrimal duct + function + what meatus it drains into
Tear duct - drains tears secreted by lacrimal sac/gland into the nasal cavity via the inferior meatus
What causes septal haematoma + how it’s formed
Trauma to the nose damaging the mucosa and pulling it away from the septum so disrupting blood supply to the septum –> blood leaks from the injured blood vessels in the mucosa –> blood collects between the mucosal lining and the septum
Immediate treatment for septal haematoma
Drainage then squash mucosa back down to the cartilage of the septum so it can get blood supply back
Name the paranasal sinuses + how many of each
2 frontal sinuses 2 maxillary sinuses 1 sphenoid sinus 1 anterior ethmoid sinus (air cells) 1 posterior ethmoid sinus (air cells)
What drains into the middle meatus (3)
Frontal sinuses, maxillary sinuses and anterior ethmoid air cells
What can you present with if your frontal sinuses are blocked
Potts puffy - large bump on forehead
What drains into the superior meatus (1)
Posterior ethmoid air cells
What does the sphenoid sinus drain into (1) + describe the location of the thing it drains into
Sphenoethmoidal recess - on the posterior roof of the nasal cavity unlike the others which drain onto the lateral walls of the nasal cavity
How are the ethmoid sinuses different to the other paranasal air sinuses
They’re a collection of air cells between the eyes instead of being one single continuous air space
What is the ground lamella
The bony structure created where the middle turbinate turns at the back of the nose to attach to the lateral nasal wall, separating the anterior and posterior ethmoid sinuses
Which sinus drains anterior to the ground lamella
Anterior ethmoid
Which sinus drains posterior to the ground lamella
Posterior ethmoid
What drains into the inferior meatus (1)
Nasolacrimal duct
What is the lamina papyracea
Paper thin bone forming medial wall of the orbit (eye socket) and the lateral surface of the ethmoid air cells
How can orbital sinusitis arise
Infection can spread from the ethmoid air cells through the lamina papyracea into the orbit
What is sinusitis
Swelling of the sinuses due to infection or allergies
Treatment of sinusitis (5)
Remove allergy trigger
Antihistamines
Treat infection - with antibiotics
Steroids (long term steroid nasal spray)
Surgery - to remove polyps (in chronic sinusitis)
Blood supply to the nose (5)
- branches of ECA
- branches of ICA (2)
Branches of the ECA:
Sphenopalatine a - MAJOR one
Greater palatine a
Superior labial a
Branches of ICA:
Anterior ethmoidal a
Posterior ethmoidal a
Sphenopalatine artery supplying the nose is a branch of what branch of the ECA
Maxillary a
Anterior and posterior ethmoidal arteries are a branch of what branch of the ICA
Ophthalmic a
A nose bleed coming from higher up the nose is likely due to which 2 arteries
Anterior and posterior ethmoidal arteries
What is the kiesselbach’s area (little’s area)
Area in the anteroinferior part of the nasal septum where 4 arteries anastomose to form the kiesselbach’s plexus
Clinical relevance of keisselbach’s area
Most common site for epistaxis
General sensory and special sensory innervation of the nose
General sensory - CN V1 + V2
Special sensory - CN I
What structures are at the back of the nasal cavity in the nasopharynx
Adenoids
Clinical problems in the middle ear could be due to a primary problem where? (think Eustachian tube)
Back of nose because Eustachian tube opens into nasopharynx
What is the fossa of rosenmuller
A space/depression behind the Eustachian tube opening in the nasopharynx
What sits in the fossa of rosenmuller in the post nasal space
Node of rouvier (lymph node)
What can cause blue ear
If node of rouvier is enlarged, it can compress the Eustachian tube
