The Nose Flashcards
What are the functions of the nose and nasal cavity
Sense of smell
Route for inspired air
Filters inspired air
Humidifies and warms inspired air
Resonating chamber for speech
What is the external nose formed of
External nose is formed of cartilage and bone covered by skin and subcutaneous tissue
Nasal bone forms prominence while cartilage forms the rest
What is the nasal cavity bound by
Roof
Lateral walls
Medial wall
Floor - hard palate
Describe the route of air from the nose into the trachea
Air enters through nares/nostrils -> enters vestibule
After vestibule air enters nasal cavity -> oropharynx -> larynx -> trachea
Describe the structural features of the lateral walls of the nasal cavity and what their functions are
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
What structures communicate with the nasal cavity
Paranasal air sinuses communicate with the nasal cavity. They drain under meatuses
Nasolacrimal duct drains into nasal cavity from the corner of the orbit
What is the nasal septum formed of
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
What is the nervous innervation to the nasal cavity
Antero-superior portion supplied by CN Va - supplies frontal, ethmoid and sphenoid sinuses
Postero-inferior portion supplied by CN Vb - supplies maxillary sinus
Describe the blood supply to the nasal cavity
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
What are the paranasal sinuses
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)
Name the paranasal air sinuses
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
Name some types of nose pathology
Septal haematoma
Saddle-nose deformity
Nasal polyps
Rhinitis
Acute sinusitis
Epistaxis
What is a septal haematoma
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
What is a saddle-nose deformity
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
What are nasal polyps
Fleshy, benign swellings of nasal mucosa
Usually bilateral
Pale or yellow apperance
Are fleshy and reddened
Not tender to the touch
What are the symptoms of nasal polyps
Blocked nose
Watery rhinorrhoea
Post-nasal drip - tickles back of throat -> chronic cough
Decreased smell and taste
Snoring
What is rhinitis and what are some symptoms of it
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
What is acute sinusitis
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
What bacteria commonly cause bacterial sinusitis
Step pneumoniae
Haemophilus influenzae
Moraxella catarrhalis
What history and examination findings are there with acute sinusitis
Recent UTI
Blocked nose
Rhinorrhoea +/- green/yellow discharge
Pyrexia
Feeling unwell
Headache
Facial pain - in are of affected sinus, worse on leaning forward
What complications can there be from acute sinusitis
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
What is epistaxis and where is it most common
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
What is the treatment for epistaxis
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
