Anatomy And Physiology Of The Nose Flashcards
What is the principal physiological function of the nose?
Humidify and warm inspired air
What can a blocked nose cause?
Dry mouth, disturbed sleep
What do tracheostomy/ Laryngectomy ‘patients need?
Humidifiers
What are other functions of the nasal airway?
Remove noxious particles from the air
Protects delicate distal lower respiratory tract
What is the olfaction?
Sense organ, housing the olfactory apparatus
What is the function of olfaction?
Smell substances for pleasure and defence purposes
Important role in protection from danger, such as fire
Central in forming positive and negative memories
Taste: while chewing, chemicals from food can activate olfactory receptors to identify food flavour
What can dysfunction in olfactory apparatus result in?
Poor quality of life
What is Choanal atresia?
Failed recanalization of the nasal fossae during foetal dvelopment
Why is choanal atresia an emergency?
Neonates are obligate nasal breathers, so will be unable to breathe
How is choanal atresia treated?
Surgical repair
How does the immune function of the nose work?
Mucus consists of compounds that are able to neutralise antigens (IgA and IgE).
What can affect the immune response of the nose ad why?
Smoking, reduces the number of cilia and change the mucous viscosity
How does the nose contribute to speech?
Nasal airflow modifies speech and produce nasal clicks or click consonants. Paranasal sinuses also contribute to viral resonance
What is nasal airflow like as it enters the nasal vestibule?
Laminar- no mixing of the different air layers at low velocity
Where does the velocity of air increase?
The nasal valve, narrowest site of upper respiratory tract
What type of airflow is observed at nasal valve?
Turbulent flow, with different layers swirling together.
What does the charge from laminar to turbulent flow allow?
The velocity to reduce, allowing prolonged contact with the nasal mucosa
What are paranasal sinuses?
Air filled, arise from the nasal cavit
What is the dorsum of the nose?
Surface between root of nose and tip
What is the opening of the nose called?
Nares
What are the opening of the nose separated by?
Columella
What is the nasal skeleton made up of?
Bony and cartilagenous components
What are the main cartlages?
Upper lateral cartilage
Lower lateral cartilage
What can nasal bone fracture result in?
Permanent deformity
Treatment for a nasal bone fracture?
Possible to correct before bone heals
Most often performed under local anaesthesia
What do yiu need to be aware of with nasal bone fracture?
Septal haematoma
What can cause a saddle nose deformity?
Nasal trauma - septal haematoma
What leads to a saddle nose deformity?
Can’t relate has no blood supply of its own
Relies on surrounding perichondrium
Haematoma results in ischaemia and necrosis of the septum
Support of the nose is lost
What is the vasculature of the skin of external nose?
Skin of external nose receives arterial supply from suratrochlear and dorsal nasal arteries and infra orbital artery
What is the vasculature of the septum and alar cartilages?
Angular artery and lateral nasal artery - both branches of the facial artery
What is the venous drainage of the external nose?
Facial vein and the internal jugular vein
What does highly anastomotic venous system of the nose allow?
Terograde preadolescent of infection to cavernous sinus via opthalmic veins
What can spread of infection to cavernous sinus be
Life and sight threatening
What can infection of cavernous sinus lead to?
Ptosis, chemosis, cranial nerve palsies
Sensory deficits of opthalmic and maxillary branches
Papilloedema, retinal haemorrhages, decreased visual acuity and blindness may occur
Fever, sepsis and tachycardia may be present
Headache with nuchal rigidity
What nerve is the innervation of external nose derived from?
Trigeminal nerve.
Describe the innervation of the external nose?
Infratroch;ear and external nasal nerves, branches of the opthalmic nerve, supply the skin of the dorsum of the nose, nasal alae and nasal vestibule
Lateral aspects of the nose are supplied by infra orbital nerve, a branch of the maxillary nerve
Motor innervation to the nasal muscles via the facial nerve
What muscle covers the dorsum of the nose>
Nasalis
What is the innervation of nasalis
Buccaneers branch of facial nerve
What is the action of nasalis?
Alar part: drepress ala laterally, dilates nostril
Transverse part: wrinkles skin of dorsum and nose
What muscle occupies the glabella
Procerus
What is the innervation of procerus
Temporal, lower zygomatic or buccaneers branches of facial nerve
What is the action of procerus?
Depress medial ends of the eyebrows, wrinkles skin over glabella- creates facial expression of frowning or when exposed to bright lights or other eye irritants
What separates the left and right nasal cavities?
Midline nasal septum
What 3 parts is the nasal cavity split into?
Vestibule
Respiratory region
Olfactory region
What is the vestibule
entrance to cavity, lineed hair bearing skin
What is the respiratory region?
Lined by ciliates pseudostratified epithelium, with mucous secreting goblet cells
What is the olfactory region?
At the apex of the nasal cavity. Lined by olfactory cells with olfactory receptors
What makes up the nasal septum
Quadrangular cartilage
Perpendicular plate of ethmoid
Vomer
Maxillary crest
Palatine bone
What are the paired bony projection from the lateral nasal wall?
Superior turbinate
Middle turbinate
Inferior turbinate
What does the presence of turbinates produce?
Meati
What does the rich vascular supply of the internal nose allow?
Allow humidification and warmin of inspired air
Branches of what arteries supply the internal nose?
ICA and ECA
What branches of the ICA supply the internal nose?
Anterior ethmoidal artery
Posterior ethmoidal artery
What branches of the ECA supply the internal nose?
Sphenopalatine artery
Greater palatine artery
Superior labial artery
Lateral nasal arteries
What are paranasal sinuses lined by?
Respiratory epithelium
What are the four paired sinuses?
Frontal
Ethmoidal
Sphenoid
Maxillary
Where do the frontal sinuses drain into?
Via the frontonasal duct into the hiatus semilunaris, within the middle meatus of the nasal cavity
What is sensation to the frontal sinus supplied by?
Supraorbital nerve
What is the arterial supply for frontal sinus?
Anterior ethmoidal artery
Where does the sphenoid sinus drain to?
Via sphenoethmoidal recess, supero-posterior to the superior turbinate
what is the sphenoid sinus innervated by?
Posterior ethmoidal nerve
What is arterial supply to sphenoid sinus?
Sphenopalatine and posterior ethmoidal artery
What is trans-sphenoid surgery most often uses for?
Pituitary adenoma (also possible in other skull base tumours)
What is the advantage of trans-sphenoidal surgery?
Avoids transcranial approach
Who is trans-sphenoidal surgery a joint procedure between?
ENT and neurosurgery
What is transphenoidal surgery in close proximity to?
Internal carotid artery
What does a CSF leak require
Repair
Where does the maxillary sinus drain to?
Via Ostia at hiatus semilunaris, underneath the frontal sinus opening
What is maxillary sinus innervated by?
Superior alveolar nerves and greater palatine nerve
What is the arterial supply of the maxillary sinus?
Branches of facial and maxillary arteries
How many ethmoidal sinuses are there?
2- anterior and posterior
Where does the anterior ethmoidal sinus open into?
Hiatus semilunaris, middle meatus via ethmoid bulla
Where does the posterior ethmoidal sinus open into?
Lateral wall of the superior meatus
What is the ethmoidal sinuses innervated by?
Anterior and posterior ethmoidal branches of the nasociliary nerve and the maxillary nerve
What is the arterial supply of the ethmoidal sinuses?
Anterior and posterior ethmoidal arteries
What is orbital cellulitis caused by?
Acute spread of infection from ethmoid or frontal sinuses
What clinical signs differentiate orbital cellulitis from pre-septal cellulitis?
Portosis, chemosis
Ophthalmopegia
Painful eye movement
Decreased visual acuity/ loss of colour vision
What is the treatment for orbital cellulitis?
Requires IV antib, nasal decongestants, CT scan +/- surgical drainage
What does the sphenoid sinus drain via?
The sphenoethmoidal recess
What does the posterior ethmoid drain via?
The lateral wall of the superior meatus
What does the anterior ethmoid, frontal and maxillary sinus drain via?
Ostiomeatal complex in the middle meatus
Where does the nasolacrimal duct open into?
Inferior meatus
What does blockage of ostiomeatal complex lead to?
Sinusitis
What is sinusitis?
Inflammation of lining of the sinus
How long does sinusitis occur for to be acute
<3 months
What causes acute sinusitis?
Viral origin
How long does sinusitis occur for to be chronic?
> 3 months
What can chronic sinusitis occur with?
Polyposis
What can chronic sinusitis cause?
Nasal obstruction
Chronic nasal discharge
Affect on smell
What can happen to static mucus?
Infection
What is the nasopharynx?
Area posterior to nasal choanae, extending down the soft palate
What is the contents of the nasopharynx?
Adenoids and tubal tonsils - lymphoid tissue, make up part of waldayers ring
Eustachian tube opening
What can obstruct Eustachian tubes?
Enlarged adenoids or post nasal space masses
What may glue ear require?
Adenoidectomy and insertion of grommets
What may unilateral glue ear indicate?
Nasopharyngeal mass
