Anatomy of the Nose and Paranasal Sinuses Flashcards
List 4 functions of the nose
1) Olfaction
2) Respiration
3) Filter and humidify
4) Drain & eliminate paranasal sinus and nasolacrimal duct secretions
5) Humidifies air
6) Defence mechanism, preventing pathogen entry
How much mucus does your nose produce every day?
1.5 litres
What is the function of the external nose?
Provides opening into nasal cavity
Describe the structure of the external nose
Bony and (predominantly) cartilaginous components
Nostrils bounded laterally by alae
Skin covering nose extends into the vestibule
What are the little hard hairs inside the external nose and state their function
Vibrissae which function to stop foreign particles and dust entering nose
Lable the components of the external ear shown on the image below
What are the openings into the nasal cavity?
Nares (nostrils)
What is the central bone (green) indicated by the arrow?
Vomer: thin sheath of bone which forms part of the nasal septum (this is part bone part cartilage)
What is the hole in the centre of the skull
Piriform aperture: where the bony and cartilaginous bits join
Name the bone located in the centre of the Piriform aperture
Vomer
List all 8 bones contributing to the skeleton of the nose (FINE SHVP)
Frontal
Nasal
Ethmoid (plus its perpendicular plate)
Sphenoid
Vomer
Palatine process of maxilla
Horizontal process of palatine bone
Inferior concha
Label the 3 improtant cartilages of the external nose skeleton and label them on the image below
1) Upper lateral cartilages
2) Lower lateral cartilages
3) Septal cartilage
What is the most common facial fracture and how may it occur?
Nasal fracture: usually by force to the face
What does a nasal fracture result in and list a complication that may arise as a result of this
Deformity of the nose: doesn’t usually cause a large amount of problem with breathing, the bigger problem is usually cosmetic ONLY
Complication: Septal haematoma
What is a septal haematoma and how would it appear?
What may occur if it goes untreated?
Main consequence of a nose fracture. A collection of blood builds up between cartilage of septum and the mucosa
Soft cherry tomato appearance
If untreated we can get necrosis and collapse of the cartilage and changes in the bridges
List 2 ways in which we treat a nasal fracture?
1) Manipulation (early): within 3 weeks in order to prevent bone resetting in the deformed shape
2) Septorhinoplasty (late) after the 3 week mark when deformed bone shape is permanent
What is the hole at the back that joins the nose to the nasopharynx
What may occur if this hole doesn’t open up in babies
Choanea
If this hole doesn’t open up in babies it results in an inability to breathe
What is the lining of the nasal cavity?
All mucosal lining which is continuous with areas draining into the cavity
EXCEPT for vestibule which is covered in skin
Label the image below
What 3 structures comprise the Medial wall (nasal septum)?
Perpendicular plate of the ethmoid bone
Vomer bone
Septal cartilage
What comprises the lateral wall of the nasal cavity?
3 Turbinates (conchae) which function to filter and humidify air:
- Superior, Middle and Inferior Turbinates
** Inferior is a bone of its own, Other 2 are part of the ethmoid bone.
What do the Turbinates (conchae) create?
5 passages within the cavity called meatuses:
1) Inferior meatus
2) Middle meatus
3) Superior meatus
4) Spheno-ethmoidal recess
5) *one passageway which pass down the middle
Above which turbinate is the spheno-ethmoidal recess located?
Above the Superior turbinate
What is located laterally on both sides of the Ethmoid bone?
How are these joined?
Ethmoidal sinuses located laterally on the ethmoid bone joined by cribriform plate
What structure projects superiorly from the cribriform plate of the Ethmoid bone?
What is its function?
Crista Galli
Anchors the falx cerebri (sheet of dura mater that separates the two cerebral hemispheres)
What is the name of the ‘projection of bone’ which descends from the cribriform plate?
The perpendicular plate: Forms the superior two-thirds of the nasal septum
What is the Infundibulum?
Groove penetrating ethmoidal labyrinth and drains frontal sinus
List 3 routes of drainage of the nasal cavity?
1) Sinuses
2) Lacrimal apparatus (nasolacrimal duct which drains into the inferior meatus)
3) Middle ear (eustachian tube)
List 4 openings of the nasal cavity
Label these on the image below
1) Cribriform plate: olfaction
2) Sphenopalatine foramen: passage of sphenopalatine artery
3) Incisive foramen: opening in the oral hard palate for vessels
4) Foramen cecum: where nasal veins drain to superior sagittal sinus (in some individuals)
What is the main blood supply to the nose
Little’s area (Kiesselbach’s plexus): conglomeration and anastomoses of many little arteries
What is the main consequence of a nasal septum deviation?
Is it congenital or aquired?
Narrowing/obstruction making breathing and air circulation through the affected nostril more difficult
Can be congenital OR acquired
Why may Nasal septum necrosis occur?
What is the term used to describe the type of deformity
Injury to nasal septum (esp if left untreated)
Saddle nose deformity
What nerve provides special sensory innervation to the nose?
CN I: Olfactory N
What 2 nerves provides general sensory innervation to the septum and lateral walls of the nasal cavity?
1) Ophthalmic (CN V1)
2) Maxillary (CN V2)
Both branches of the trigeminal nerve
What nerve supplies the ‘Antero-superior’ nasal cavity?
What CN is this a branch off?
Nasociliary nerve: branch of the Ophthalmic N (V1)
Innervates the septum and lateral wall of the ‘antero-superior’ nasal cavity
What 2 nerves supplies the ‘Postero-inferior’ nasal cavity?
What CN are these branchs off?
1) Nasopalatine N: inneravtes the septum
2) Branches of the Greater Palatine N: innervates lateral wall
Both branches of the Maxillary N (V2)
What 2 nerves supply the external nose and what CN are these branches off?
Incl what areas of the external nerve each innervates
1) External nasal N (CN V1): innervates the dorsum, ala, vestibule
2) Infraorbital N (CN V2): innerates the lateral external walls
Both branches of the Trigeminal nerve
The Nasocillary nerve (branch of V1) is also responsible for what important reflex?
Corneal reflex: Nasocillary nerve is the afferent branch of the corneal reflex
What epithelium is found in the Respiratory region of the nasal cavity?
Pseudostratified columnar ciliated, with goblet cells
What epithelium is found in the Olfactory region of the nasal cavity?
Olfactory cells with olfactory receptors
Lines the upper surface of superior turbinate and spheno-ethmoidal recess + corresponding septum and roof
What Glands found in the nose have a specific function involving sensing smells
Bowmans glands function to bring smells into the nose (specific function to do with sense of smell)
What are Paranasal sinuses and state 3 functions of these
Paired, mucous membrane lined out-pocketings of the nasal cavity which are filled with air
1) May contribute to conditioning of inspired air
2) Resonance
3) Reduce weight of skull
List my 4 paranasal sinuses which drain into the nasal cavity
Indicate each on the image below
1) Maxillary
2) Frontal
3) Sphenoid
4) Ethmoid
Compare sinuses at birth to sinuses in an adult
At birth sinuses are non-existent/small. As we age the sinuses develop and grow (fill with air) which serves to reduce the weight of the skull and changes the shape of the face to more closely resemble the structure of an adult face
What forms the roof and floor of the maxillary sinus?
Roof: The floor of the orbit
Floor: Alveolar part of maxilla (specifically the roots of first 2 molars supplied by the superior alveolar N which is a branch of the Maxillary nerve)
What is found posteriorly to the Maxillary sinus
Pterygopalatine and infratemporal fossae
What is the clinical implication for spread of infection from the maxillary sinus?
Close proximity (alveolar part of maxilla) means dental infections can spread into the maxillary sinus and extend intracranially
State whether each of the following is present and birth and when it enlarges to resemble an adult:
a) Maxillary sinus
b) Frontal sinus
c) Sphenoid sinus
a) Maxillary: Present at birth, enlarging from about 8yrs
b) Frontal: Not present at birth, as it grows its size varies amoung individuals
c) Sphenoid sinus: small at birth, enlarging after puberty
What is the frontal sinus closly related to anatomically?
Related to anterior cranial fossa and the orbit
Where is the sphenoid sinus located?
Located within the sphenoid bone
List 4 anatomical structures closly related to the Sphenoid sinus
1) Pituitary fossa
2) Cavernous sinus and ICA
3) Middle cranial fossa
4) Roof of nasopharynx
What are the 3 types of Ethmoid air cells in the Ethmoidal sinus?
State where each drains
1) Anterior cells: Drains into middle meatus via infundibulum
2) Middle cells: Drains directly into middle meatus
3) Posterior cells: drains into superior meatus
Where is the ethmoidal sinus and ethmoidal air cells located?
Between orbit and nasal cavity
States the drainage of the following:
Maxillay
Frontal
Sphenoid
Ethmoids (3)
Nasolacrimal ducts
(Hint all middle EXCEPT SPeN)
Maxillary: drains into middle meatus
Frontal: drains into middle meatus
Sphenoid: drains into spheno-ethmoidal recess
Ethmoids:
- Anterior→ Middle meatus
- Middle → Middle meatus
- Posterior→Superior meatus
Nasolacrimal duct: drains into inferior meatus
State 4 locations that infection of the nasal cavity may spread through and include via what structures
1) Anterior cranial fossa: via cribriform plate
2) Middle ear: via Eustachian tube
3) Paranasal sinuses
4) Lacrimal apparatus and conjunctiva: via nasolacrimal duct
What is Rhinitis and is it acute or chornic?
Inflammation of nasal mucosa leading to swelling & increased volume of secretion
Can be acute OR chronic
Give 3 causes of Rhinitis
1) Infective (usually viral)
2) Allergic
3) Non-Allergic
Chronic Rhinitis may progress to what 2 things?
Nasal polyps or sinusitis
List 4 things thought to be associtaed with Rhinitis
Linked to chronic rhinosinusitis
May be associated with asthma, aspirin, allergy
Give 3 main symptoms of Rhinitis
1) Nasal obstruction
2) Post nasal drip/ rhinorrhoea
3) Snoring / obstructive sleep apnoea
What is Sinusitis?
When does it commonly occur and is it usally bacterial or viral?
Inflammation of the mucosal lining of the sinuses (most commonly occurs following a cold)
Usually viral with a secondary bacterial infection
List 2 common bacteria responsible for a secondary infection of Rhinitis
S pneumoniae and H influenzae
