Anatomy and Physiology of the Nose Flashcards
What are the main functions of the nose?
Nasal airway
Olfaction (smell)
Immune
Speech
What does the nose do to inspired air?
Warms and humidifies it
After which surgeries may a patient need need to humidifier to prevent drying out of the lower airways?
Tracheostomy
Laryngectomy
What in the function of the cilia on the walls of the nasal cavity?
Trap dust and harmful particles.
Why do we smell?
For pleasure and to warn against danger e.g. fire
How does smell link to taste?
While chewing, chemicals from food activate olfactory receptors to indentify food flavour.
What is choanal atresia of the nose?
Failed recanalization of the nasal fossae during foetal development
Why is choanal atresia an emergency in neonates?
They are obligate nasal breathers so will be unable to breathe.
How is choanal atresia fixed?
Surgery
How does the nose play a role in immunity?
Mucus consists of compounds which can neutralize antigens.
Which immunoglobulins are found on the mucosal surfaces of the nose?
IgA
IgE
What can reduce number of nasal cilia and changes mucus viscosity?
Smoking
How does the nose affect speech?
Provides vocal resonance and nasal clicks
->if bunged up because of a cold, voice is thicker and less easily understood
At which point does nasal flow turn from laminar to turbulent?
When it goes through the nasal valve
Why is it important that nasal laminar flow turns into turbulent flow?
Decreases velocity so there is prolonged exposure to nasal mucosa
->this is probably to give more time to trap dust, neutralize pathogens, smell, etc.
What are the paranasal sinuses?
Air filled cavities
What is the function of paranasal sinuses?
Debated but suggested decreases weight of skull?
Possible heat insulation?
Humidification?
What is meant by the dorsum of the nose?
Surface between root of nose and tip
What is the name of the openings of the nose?
Nares
What are the two nares separated by?
Columella
There are two parts of the nasal skeleton- bone and cartilage. Describe the bones of the nasal skeleton.
Paired, symmetrical and oblong
Name the two main paired cartilages of the nose.
Upper lateral cartilage
Lower lateral (alar) cartilage
Which bones do the nasal bones articulate with:
1. superiorly
2. laterally
- Frontal bones
- Maxilla bones
What are the two paired cartilages of the nose attached to and supported by?
Septal cartilage
What is the most common facial fracture?
Nasal fracture
What can a nasal fracture result in?
Permanent deformity
How can a nasal fracture be corrected?
Via surgery but has to be quick before bone heals
When assessing nasal injury, what trauma-related issue must you look out for?
Septal haematoma
What can untreated septal haematoma result in?
Saddle nose deformity
What is a septal haematoma?
Collection of blood between the perichondrium and cartilage of the nasal septum.
What happens if the septal haematoma is not correctly drained?
Mucal perichondrium is not replaced onto cartilage leading to ischaemia and necrosis of septum.
What does the saddle provide the nose with?
Support, therefore, in a saddle nose deformity, the support to the nose is lost.
Where does the skin of the external nose receive blood from?
Supratrochlear and dorsal nasal arteries.
Infraorbital artery.
Which artery are the supratrochlear and dorsal nasal arteries branches of?
Ophthalmic artery
Which artery is the infraorbital artery a branch of?
Maxillary artery
Where do the septum and agar cartilages receive arterial blood from?
Angular artery
Lateral nasal artery
Which artery are the angular and lateral nasal artery branches of?
Facial artery
Describe the venous drainage of the nose.
Drained by facial vain into internal jugular vein.
Describe what is meant by the danger triangle of the nose.
Highly anastomotic venous system of nose allows retrograde spread of infection to the cavernous sinus via ophthalmic veins.
Life and sight threatening.
What are some of the clinical signs of Cavernous sinus thrombosis?
Ptosis (drooping of eyes)
Chemosis (eye irritation)
Cranial nerve palsies
Which nerves are are danger of cranial nerve palsies in cavernous sinus thrombosis?
III- Oculomotor
IV- Trochlear
V- Trigeminal
VI- Abducens
What are some of the potential consequences of cavernous sinus thrombosis?
Papilledema (swelling of optic disc)
Retinal haemorrhages
Decreased visual acuity
Blindness
What may be present clinically in those with cavernous sinus thrombosis?
Fever
Tachycardia
Sepsis
Headache w neck stiffness
Which nerve is the innervation of the external nose derived from?
Trigeminal nerve
Which nerve supplies motor innervation to the muscles of the nose?
Facial nerve
Which nerves supply the skin of the dorsum of the nose, nasal alae and nasal vestibule?
Intertrochlear and external nasal nerves- both branches of the ophthalmic nerve.
Which nerve supplies the lateral aspects of the nose?
Infraorbital nerve, branch of maxillary nerve
What are the main two muscles of the nose?
Nasalis
Procerus
Which muscle covers the dorsum of the nose?
NasalisW
Which muscle is a small pyramidal shape superior to the dorsum occupying the glabella(between eyebrows)?
Procerus
What is the innervation of the nasalis muscle?
Buccinator branch of facial nerve
What is the action of the nasalis muscle?
Alar part- depresses ala laterally, dilates nostrils
Lateral part- wrinkles skin of dorsum
What is the innervation of the procerus muscle?
Temporal, lower zygomatic or buccal branches of facial nerve.
What is the action of the procerus muscle?
Depresses medial ends of eyebrows
Wrinkles skin over glabella (between eyebrows)
Creates frowning expression when exposed to bright light or eye irritants
Name the three parts of the nasal cavity.
- Vestibule
- Respiratory region
- Olfactory region
What is the vestibule of the nose?
Entrance to nasal cavity, lined with hair bearing skin
Describe the histology of the respiratory region of the nasal cavity.
Lined by ciliated pseudostratified epithelium with mucus secreting goblet cells.
Describe the olfactory region of the nasal cavity.
Apex of nasal cavity, lined with olfactory cells w olfactory receptors.
What does the nasal septum do?
Divides right and left nasal passages
Name the three paired bony projections from the lateral nasal wall.
Turbinates/conchea
- Superior turbinate
- Middle turbinate
- Posterior turbinate
What does the presence of the three tubinates form?
Superior, middle and inferior meatus
Why does the internal nose have a rich vascular supply?
Allows humidification and warming of air
The internal nose has a rich blood supply from the internal and external carotid arteries. Name the branches of the internal AND external.
Internal Carotid:
-anterior ethmoidal artery
-posterior ethmoidal artery
External Carotid:
-Sphenopalatine artery
-Greater palatine artery
Superior labal artery
-Lateral nasal artery
Epsitaxis?
Nosebleed
Where is the most common area for epsitaxis?
Little’s area on the anterior septum
Which plexus is found at the Little’s area?
Kiesselbach plexus
Where would posterior nasal bleeding usually come from?
Woodruff plexus
Which plexus is easier to access and cauterise under local anaesthetic?
Kiesselbach plexus
Which type of bleed is more likely to require nasal packing?
Posterior bleeding via Woodruff plexus
What is usual first aid for a noseblled?
Pinching of the nose
Which type of bleed does not respond to nose pinching?
Posterior bleed via Woodruff plexus
What are some surgical management options for epistaxis?
Endoscopic ligation of sphenopalatine artery
What are paranasal sinuses?
Air filled cavities lined by respiratory epithelium.
Name the four groups of paranasal sinuses.
HINT- named according to which bone they are located in
Frontal
Maxillary
Sphenoid
Ethmoid
Which sinuses are the most superior?
The 2 frontal sinuses
What is the arterial supply for the frontal sinuses?
Anterior ethmoidal artery
What is the sensation supply for the frontal sinuses?
Supraorbital nerve (branch of ophthalmic nerve).
What is the drainage for the frontal sinuses?
Frontonasal duct into hiatus semilunaris
Which sinuses are most posterior?
Sphenoid sinuses
What is the sensation supply for the sphenoid sinuses?
Posterior ethmoidal nerve (branch of ophthalmic nerve)
What is the arterial supply for the sphenoid sinuses?
Sphenopalatine artery
Posterior ethmoidal artery
What is the drainage for the sphenoid sinuses?
Spheno-ethmoidal recess
Which type of surgery may be carried out for the resection of pituitary adenomas?
Trans-sphenoidal surgery
What are the risks of a trans-sphenoidal surgery?
Close proximity to internal carotid artery so high bleeding risk.
Risk of CSF leak, which will need repaired.
Which of the sinuses are the largest?
Maxillary sinuses
What is the drainage for the maxillary sinuses?
Hiatus semilunaris
What is the arterial supply for the maxillary sinuses?
Branches of facial and maxillary arteries
What is the innervation for the maxillary sinuses?
Superior alveolar nerves
Greater palatine nerve
Both branches of maxillary nerve
There are two ethmoidal sinuses on either side of the face; an anterior and a posterior.
What is the arterial supply for the ethmoidal sinuses?
Anterior ethmoidal artery
Posterior ethmoidal artery
There are two ethmoidal sinuses on either side of the face; an anterior and a posterior.
What is the innervation for the ethmoidal sinuses?
Anterior and posterior ethmoidal branches of the nasociliary nerve
What is orbital cellulitis?
Sight threatening emergency!
Acute spread of infection from the sphenoid or frontal sinuses.
What are some of the clinical signs of orbital cellulitis?
Proptosis (eye swelling)
Chemosis (eye irritation)
Ophthalmoplegia (weakness/paralysis in eye movements)
Loos of colour vison and decreased visual acuity
In those with orbital cellulitis, which colour will they lose vision of first?
Red
What is the treatment of orbital cellulitis?
IV antibiotics
Nasal decongestants
Which imaging will be done in those with orbital cellulitis?
CT scan
Sometimes surgery can be done in treatment of orbital cellulitis…what can be done?
Drainage
What is sinusitis?
Inflammation of lining of sinuses
What is the cause of acute sinusitis (<3months)?
Usually viral
Chronic sinusitis is diagnosed when it’s been present for >3months. It can be with or without polyposis.
Describe the symptoms of chronic sinusitis.
Nasal obstruction
Chronic nasal discharge
Affect on smell
What is the post-nasal space/ nasopharynx?
Area posterior to nasal cholanae extending down to the soft palate
What are the contents of the post-nasal space/nasopharynx?
Adenoids
Tubal tonsils
Eustachian tube opening
What may enlarged adenoids or eustachian tube obstruction result in?
Glue ear (otitis media with effusion).
