The Nose

Question 1

What are the functions of the nose and nasal cavity

Answer 1

Sense of smell

Route for inspired air

Filters inspired air

Humidifies and warms inspired air

Resonating chamber for speech

Question 2

What is the external nose formed of

Answer 2

External nose is formed of cartilage and bone covered by skin and subcutaneous tissue

Nasal bone forms prominence while cartilage forms the rest

Question 3

What is the nasal cavity bound by

Answer 3

Roof

Lateral walls

Medial wall

Floor - hard palate

Question 4

Describe the route of air from the nose into the trachea

Answer 4

Air enters through nares/nostrils -> enters vestibule

After vestibule air enters nasal cavity -> oropharynx -> larynx -> trachea

Question 5

Describe the structural features of the lateral walls of the nasal cavity and what their functions are

Answer 5

Lateral walls have conchae and meatuses

Conchae are bony projections that curve down - forms space underneath conchae (meatuses)

Conchae are lined by respiratory mucosa

Conchae slow airflow by causing turbulence of airflow as the air hits the conchae

Conchae also increase surface area over which air passes

Question 6

What structures communicate with the nasal cavity

Answer 6

Paranasal air sinuses communicate with the nasal cavity. They drain under meatuses

Nasolacrimal duct drains into nasal cavity from the corner of the orbit

Question 7

What is the nasal septum formed of

Answer 7

Formed of a bony part and a cartilaginous part

Bony part formed by perpendicular plate of ethmoid and the vomer

Cartilaginous part formed by septal cartilage

Question 8

What is the nervous innervation to the nasal cavity

Answer 8

Antero-superior portion supplied by CN Va - supplies frontal, ethmoid and sphenoid sinuses

Postero-inferior portion supplied by CN Vb - supplies maxillary sinus

Question 9

Describe the blood supply to the nasal cavity

Answer 9

Arterial supply by branches of opthalmic and maxillary arteries

• Anterior and posterior ethmoid arteries from opthalmic
• Sphenopalatine and greater palatine from maxillary

Arteries anastomose in anterior septum in Little’s area/Kiesselbach’s plexus

• Most common source of epistaxis

Venous drainage is into pterygoid venous plexus as well as cavernous sinus and facial vein

Question 10

What are the paranasal sinuses

Answer 10

Air filled spaces that are extensions of the nasal cavity

Either rudimentery or absent at birth

Lined by respiratory mucosa

Help humidify and warm inspired air and decrease weight of the skull

Drain into the nasal cavity via ostia into one of the meatuses (mostly middle)

Question 11

Name the paranasal air sinuses

Answer 11

Frontal
Ethmoid - air cells in this sinus are split into anterior, middle and posterior. Ethmoid sinus forms medial wall of orbit -> medial orbital wall thin

Sphenoid

Maxillary - roots of upper teeth sometimes project into maxillary sinus -> dental abscesses can cause maxillary sinusitis

Question 12

Name some types of nose pathology

Answer 12

Septal haematoma

Saddle-nose deformity

Nasal polyps

Rhinitis

Acute sinusitis

Epistaxis

Question 13

What is a septal haematoma

Answer 13

Where injury to the nose buckles the septum, shearing the blood vessels

Causes blood to accumulate in the sub-perichondrium

This separates the perichondrium from the cartilage, depriving it of its blood supply -> avascular necrosis if not treated

Question 14

What is a saddle-nose deformity

Answer 14

Untreated septal haematoma leads to avascular necrosis of cartilaginous septum -> saddling of nasal dorsum as have lost scaffolding of the nose

Can develop infections in collecting haematoma

Question 15

What are nasal polyps

Answer 15

Fleshy, benign swellings of nasal mucosa

Usually bilateral

Pale or yellow apperance

Are fleshy and reddened

Not tender to the touch

Question 16

What are the symptoms of nasal polyps

Answer 16

Blocked nose

Watery rhinorrhoea

Post-nasal drip - tickles back of throat -> chronic cough

Decreased smell and taste

Snoring

Question 17

What is rhinitis and what are some symptoms of it

Answer 17

Inflammation of the nasal mucosal lining

Common causes: simple acute infective rhinitis (viral), allergic rhinitis

Symptoms: nasal congestion, rhinorrhoea, sneezing, post-nasal drip, generally unwell nasal irritation

Question 18

What is acute sinusitis

Answer 18

Symptomatic inflammation of mucosal lining of nasal cavity and paranasal air sinuses

Often secondary to viral infection

Primary infection leads to decreased ciliary function, oedema of nasal mucosa, sinus ostia and increased nasal secretions which leads to drainage of sinus becoming impeded - causes stagenent secretions within sinus -> breeding ground for bacteria and secondary infection

Question 19

What bacteria commonly cause bacterial sinusitis

Answer 19

Step pneumoniae

Haemophilus influenzae

Moraxella catarrhalis

Question 20

What history and examination findings are there with acute sinusitis

Answer 20

Recent UTI

Blocked nose

Rhinorrhoea +/- green/yellow discharge

Pyrexia

Feeling unwell

Headache

Facial pain - in are of affected sinus, worse on leaning forward

Question 21

What complications can there be from acute sinusitis

Answer 21

Infection of air cells in ethmoid sinuses -> break through thin medial orbital wall -> spreads into orbit causing orbit cellulitis

Infection may spread and involve optic nerve or track back to involve intracranial structures

Question 22

What is epistaxis and where is it most common

Answer 22

Epistaxis - nose bleed. Are very common, usually treated with simple first aid

Arises spontaneously or due to minor trauma to the nose. Can have an underlying systemic disease that causes epistaxis

Little’s area is most common site of origin for nosebleeds but some arise from sphenopalatine artery

Question 23

What is the treatment for epistaxis

Answer 23

Apply simple compression and lean forward

Cold pack around bleeding - vasoconstriction

Give vasoconstrictor - e.g. adrenaline

Cauterise using silver nitrate or another cauterising agent

Anterior packing using nasal tampons

Posterior packing

Surgical intervention