Nose And Paranasal Sinuses

Question 1

Functions of the nose and nasal cavity

Answer 1

Sense of smell

Provides a route for inspired air

Filters inspired air - trapping particles in nasal hair or mucous

Moistens and warms inspired air (V vascular)

Resonating chamber for speech

Question 2

What makes up the external nose? Why is it susceptible to fracture in facial injury? Which is most commonly fractured? Why do you sometimes have to ask them to come back after the initial injury?

Answer 2

Cartilage and bone: nasal bone, frontal process of maxilla

Prominence of nasal bones

Nasal bone most susceptible

Ask to Combe back once swelling has reduced (2-3 days)

Question 3

What is the vestibule? What’s it lined with?

Answer 3

Cavity opening

Lined with skin containing sebaceous/ sweat glands and hair

Question 4

What are the boundaries of the nasal cavity?

Answer 4

Medial wall - nasal septum

Roof- anteriorly frontal & nasal bones, middle cribriform plate of ethmoid, posteriorly sphenoid

Floor- hard palate

Lateral wall- ethmoid labyrinth, palatine bone, maxilla

Question 5

Why is the lateral wall irregular? What’s the purpose of this?

Answer 5

Bony projections (conchae) superior, middle, inferior part of ethmoid bone

Under each: meatuses: superior, middle (opening into maxillary air sinus), inferior (cry- nose run as nasal lacrimal duct runs through)

Slows airflow by causing turbulence which increases SA over which air passes (humidify, warm)

&

Openings under meatuses allow for drainage of paranasal air sinuses & nasolacrimal duct into nasal cavity

Question 6

What’s the nasal septum made from?

Answer 6

Bony part:
Perpendicular plate of ethmoid & volmer bone

Cartilaginous part:
Septal cartilage

Question 7

What is a saddle-nose deformity and how it is caused? How do you prevent this?

Answer 7

cartilage of nasal septum relieves blood supply from overlying perichondrium - injury to nose e.g. punch -> buckle septum and shear Bvs -> blood accumulates sub-perichondrium

✅aspartate blood and tamponade with dressings

Untreated septal haematoma leads to avascular necrosis of cartilaginous septum (saddling of nasal Dorsum)

Can also develop infection in the collecting haematoma (septal abscess further increases risk avascular necrosis)

Question 8

sensory Nerve innervation to the nose and nasal cavity

Answer 8

V1 - superior nose and first part of nasal Cavity
(ophthalmic)

V2 - second part of nasal Cristy and nasopharynx (maxillary)

V3- lower part of mouth (mandibular)

Trigeminal divisions

Question 9

What mucous membranes lines the nasal cavity? what is their functions?

Answer 9

Top is olfactory mucous membrane - houses olfactory receptor neurones CN1

Majority respiratory mucous membrane - pseudostratified columnar ciliated epithelium rich goblet cells, filters, humidifies, warms

Question 10

What are nasal polyps? What are some symptoms and some red flags?

Answer 10

fleshy, benign swellings of nasal mucosa

Usually bilateral

Common >40yrs

Pale/ yellow, fleshy, reddened

Symptoms:
Blocked nose, watery rhinorrhoea, post-nasal drip, decreased smell/ taste

Unilateral polyp +/- blood-tinged secretion May suggest tumour 🚩 (in children more likely foreign body stuck)

Question 11

What is Rhinitis?

Answer 11

Inflammation of nasal mucosal lining

Causes: acute infective rhinitis (viral cold), allergic rhinitis

Symptoms: nasal congestion, rhinorrhoea, sneezing, nasal irritation, postnasal drip

Question 12

Describe the blood supply to the nasal cavity. Where’s the most common site for epistaxis?

Answer 12

Arterial supply arises from branches of ophthalmic A and maxillary A -> anastomoses in anterior septum (Kiesselbach’s plexus/ Little’s area) - most common source of epistaxis

Venous drainage into pterygoid venous plexus, (cavernous sinus and facial vein)

Rich blood supply allows for warming and humidification inspired air

Question 13

How often do you get posterior epistaxis? How would you manage it?

Answer 13

10% - from spehnopalatine A

Difficult to treat - nasal packing, tamponade (nasal tampons)

Question 14

What are paranasal sinuses?

Answer 14

Air filled spaces that are extensions of the nasal cavity (rudimentary or absent at birth)

Lined with respiratory mucosa (ciliated and secrete mucous)

Named according to the bone they’re found: frontal, ethomoidal, sphenoid, maxillary

Help humidify and warm inspired air and reduce weight of skull

All drain into nasal cavity via ostia in a meatus (most into middle meatus)

Question 15

What is sinusitis? Which sinus is most commonly affected why?

Answer 15

Infections in nasal/ oral cavity can involve sinuses - symptomatic inflammation of mucosal lining of nasal cavity and paranasal air sinuses

Primary infection -> reduced ciliary function, oedema of nasal mucosa, sinus ostia and increased nasal secretions (drainage from sinus impeded). Can lead to bacterial infection e.g. streptococcus pneumoniae/ haemophilus influenza, moraxella catarrhalis

Often secondary to viral infection of nasal cavity (<10days), recent URTI, blocked nose, rhinorrhoea (green/ yellow), pyrexia, headache/ facial pain- worse leaning forwards

Maxillary most commonly bc has to work against gravity to drain mucous

✅self-limiting (analgesia, antipyretic, steam inhalation)

Question 16

What are the air sinuses and where are they located? What is there sensory innervation?

Answer 16

Frontal - above orbital fossa medial

Ethmoidal- on cribriform plate, top nasal cavity

Sphenoid - 2 behind nose between eyes

All of above- Va (trigeminal N ophthalmic branch)

Maxillary- biggest, bottom and lateral of nasal cavity, drain high into nasal cavity, roots of upper teeth can project into it. Trigeminal N - maxillary branch

Question 17

When is acute bacterial sinusitis more likely?

Answer 17

Symptoms particularly severe at onset, last >10 days without improving <4 weeks, symptoms worsen after initial improvement (secondary infection)