Lecture 17- The nose Flashcards
functions of the nose
- Smell and taste
- Breathing- route for inspired air
- Filters inspired air trapping particle sin nasal hair and mucous
- Moistens (humidifies) and warms
- Resonating chamber for speech
what is the external nose called
vestibule
anterior nares
nostrils/ nasal apertures
posterior nares
posterior nasal apertures (choanae)
external nose is made up of
cartilage (near the nostrils) and bones (at the top)
important bone of the nose
nasal bone (paired bone) found right at the top of the nose
- Clinical correlates of nasal bone
v
skin inside the vestibule
lined with skin containing sebaceous/sweat glands and hair–> filters inspired air
the nasal cavity has bony boundaires and is divided into left and right by the
midline spetum
features of the 2 lateral walls of the nasal cavity
- Irregular due to presence of bony projections (conchae/ turbinates)
- Superior (part of ethmoid)
- Middle (part of ethmoid)
- Inferior (other bone
what are the bony projections of the lateral walls reffered as
conchae or turbinates
turbinates create
meatues
- superior
- middle
- inferior
- Openings under the meatuses allows for drainage of the
- Paranasal air sinus in nasal cavity
- Nasolacrimal duct in nasal cavity
why do the lateral walls of the nasal cavity have this irregular anatomy?
- slows airflow by causing turbulence of airflow
- increases surface area over which air passes
roof of the nasal cavity
the roof of the nasal cavity is formed by nasal cartilages and several bones, chiefly the nasal and frontal bones, the cribriform plate of the ethmoid , and the body of the sphenoid.
epithelium of the respiratory part of the nose
lined by a ciliated psudeostratified epithelium, interspersed with mucus-secreting goblet cells.
Olfactory region of the nose –
located at the apex of the nasal cavity. It is lined by olfactory cells with olfactory receptors.
the roof of the nasal cavity can be used to
- to access parts of the brain found on the cranial floor
- Transsphenoidal surgical approach- e.g. gaining access to the pituitary gland via the sphenoid bone
floor of the nasal cavity
The floor, wider than the roof, is formed by the palatine process of the maxilla and the horizontal plate of the palatine bone, i.e., by the palate.
Medial wall of the nasal cavity-
The septum
The septum
- Consists of a bony and cartilaginous part
- Anterior= septal cartilage
- Posterior= perpendicular plate of the ethmoid bone and the vomer bone
clinical correlate- septa haematoma
- Potential complication from nasal injury
- Buckling(bending) of cartilage due to trauma
- Tears/shears blood vessel
- Accumulation of blood
- Strips perichondrium away from cartilage (nasal septum)
- Starving cartilage of blood supply
- Cartilage dies fibrosis and affects shape
- Infection can be an issue
diagnosis of septa haemtoma
- Diagnosis- must look up the nostrils for swelling
- septa haematoma treatment-
must be incised and drain and a tamponade placed to stick perichondrium back onto cartilage
But if you don’t treat septal haematoma-
Saddle nose deformity (equivalent tof cauliflower ear)
Saddle nose deformity
untreated septa haematoma leads to avascular necrosis of cartilaginous septum
- saddling of nasal dorsum (saddle-nose deformity)
ALWAYS EXAMINE FOR SEPTAL HAEMATOMAS IN PTS PRESENTING WITH NASAL INJURY
questionL while picking her nose, the queen accidently catchers her nail on the nasal mucosa. the pain is itnense causing her to wince. Which cranial nerve carriers genral sensation from the nasal cavity
- Trigeminal – Va/Vb- maxillary
Nerve innervation to the nose and nasal cavity
Trigeminal nerve (V)
branches of the trigeminal nerve
- V1- Ophthalmic
-
V2- Maxillary
- Majority of nasal cavity (particularly lateral wall) supplies by V2
- V3- mandibular
Lining of the Nasal cavity:
- Vestibule
lined by skin
Lining of the Nasal cavity:
- respiratory muscous membrane
- Pseudostratified columnar epithelium
- Rich in goblet cells
- Filters (mucous and cilia)
- Humidifies and warms(rich blood supply)
Lining of the Nasal cavity:
- Olfactory mucous membrane
- Contains dendrites of olfactory nerves
- Covers over roof of the nasal cavity (including superior concha/superior part of the septum
Nasal polyps
Fleshy, benign swelling of the nasal mucosa
polyps imaging
- Polyps look slightly lighter
- In this pic: Emerge out of the middle meatus (between middle and inferior turbinate’s)
polyps are usually
bilateral and very common in those over 40
- Symptoms of nasal polyps
- Blocked nose and water rhinorrhoea
- Post-nasal drip
- Drip goes into the pharynx and larynx- irritation and cough
- Decrease smell and reduced taste
- Sinusitis- blockage of the sinus air cavities
- Unilateral poly +/- blood tinged secretion may suggest tumour - cancer
Rhinitis:
Inflammation of the nasal mucosa lining
rhinitis is usually
bilateral- entire nasal cavity affected
rhinitis has
many causes
common causes =
- Simple acute infective rhinitis (viral- common cold)
- Allergic rhinitis- similar symptoms to infective rhinitis
symptoms of rhinitis
- Nasal congestion
- Rhinorrhoea – runny nose
- Sneezing
- Nasal irritation
- Postnasal drip
question
- Foreign body
Infective and allergic rhinitis would be bilateral
Nasal cancers and nasal polyp - not seen in children
Rich blood supply to the nasal mucosa
*
Allows for warming and humidification of inspired air
*
nasal mucosa and blood vessels are
easily injured e.g. epistaxis (nose bleed)
The nose receives blood from both the
-
Internal and external carotid arteries:
-
Internal carotid branches:
- Anterior ethmoidal artery
- Posterior ethmoidal artery
- The ethmoidal arteries are branch of the ophthalmic artery. They descend into the nasal cavity through the cribriform plate
-
External carotid branches:
- Sphenopalatine artery
- Greater palatine artery
- Superior labial artery
- Lateral nasal arteries
-
Internal carotid branches:
In addition to the rich blood supply, these arteries form
anastomoses with each other. This is particularly prevalent in the anterior portion of the nose .
hat is this anastomoses called in the anteiror nose
-
Keisselbachs plexus or Little’s area
- Most common source of bleeding in epistaxis (e.g. picking of nose)
- Easily treatable with simple first aid measure- pinching nose
- Usually just one sided
- Sphenopalatine artery found
- Posteriorly
- Small proportion of nosebleeds
- Potentially more serious and difficult to reatch(harder to reach to tamponade
- Bleeding in both nostrils
The veins of the nose tend to
follow the arteries.
veins drain into
They drain into the pterygoid plexus, facial vein or cavernous sinus.
how to treat epistaxis when they occur (simple)
pinch the soft part of the nose to apply pressure to the keisselbachs plexus (little area)
Paranasal sinuses
- Air filled spaces that are extension of the nasal cavity
- Rudimentary or absent at birth
paranasal sinuses lined with
- respiratory mucosa
- Ciliated and secretes mucous
paranasal sinuses named according to
the bone in which they are found
functions of the paranasal air sinuses
- Various functions – humidify and warm inspired air
- Reduce weight of the skull
paranasal sinuses drain into the …….. ……… via …….. ………….
nasal cavity via small channels (ostia in the middle conchia) into a meatus (mostly)
- Infection of nasal cavity involving sinuses
- sinusitis
- Maxillary sinus most commonly infected
name and label the paranasal air sinuses
- Frontal air sinuses (can have 2,3 or 4)
- Ethmoid air sinuses
- Maxillary air sinuses
- Sphenoidal air sinuses
important anatomical relations of the paranasal sinuses include the
nasal cavity, orbit and anterior cranial fossa
(roots of upper teeth can sometimes project into maxillary sinus)
general sensory innervation of the paranasal sinuses
from branches of CN V
- Va (frontal, ethmoidal and sphenoid sinus)
- Vb (maxillary sinus)
plain facial X-ray sinuses
CT showing paranasal sinuses
CT showing conchae and meatus
Acute sinusitis
Symptomatic inflammation of mucosal lining of the nasal cavity and paranasal air sinuses
- Sinusitis is often secondary to
- viral infection of nasal cavity
- Symptoms typically peak early and resolve gradually (last <10days)
- Clinical diagnosis of sinusitis (i.e. based on history and exam)
- Recent URTI
- Blocked nose and rhinorrhoea +/- green/yellow discharge
- Pyrexia
- Headache/facial pain
- Worse on leaning forward
treatment of sinusitis
- Self-limiting- treatment is symptomatic e.g. Analgesics, antipyretics, steam inhalation
pathophysiology of sinusitis
- Primary infection e.g. rhinitis leads to reduced ciliary function, oedema of nasal mucosa and sinus ostia and increased nasal secretions
- Drainage from sinus impeded
acute bacterial sinusitis
more likely if
- symptoms particularly severe at onset
- symptoms >10 days without imporvement but <4 weeks
- symptoms wosen after an intitial imporvement (suggesting secodnary bacterial infections)
which paranasal sinus is most commonly affected
maxillary sinus
why is the maxillary sinus most likely affected in sinusitis
Maxillary sinus most commonly affected
- Opening is high up – has to work against gravity
- Stagnant secretions within the sinus become ideal for bacterial breading
bacterial causes of sinusitis
- Pneumonia, H. influenzae and Moraxella catarrhalis
