Week 7.0 - Nose Flashcards
Which bones contribute to the bony skeleton of the nose?
- Frontal bone
- Nasal bone
- Ethmoid bone
- Maxilla (palatine process)
- Sphenoid
- Vomer
What contributes to the cartilage of the nose?
- Septal cartilage
- Major and minor alar cartilage
What is the most common facial fracture?
-Nasal fracture
Give a common complication of nasal fracture
-Septal haematoma
What are choanae?
-Exit at the posterior of nose into nasopharynx
What are concha (turbinates)? What is their function?
-Grooves in the lateral wall of the nasal cavity which act to mix air (create turbulent flow) and increase the SA of the nose
What are superior, middle and inferior meatus?
-Passageways under corresponding concha which are openings from the sinuses, eustachian tube and nasolacrimal duct into the nasal cavity
What is the sphenoethmoid recess?
-A passage way located above the superior conchae
Describe the ethmoid bone
- Located in the midline of the anterior fossa of the cranial cavity
- 2 ethmoidal labyrinths of air cells joined by cribriform plate
- Cribriform plate has many holes penetrated by CN1 and crista galli which anchors falx cerebri
- Also has infundibulum - a groove which penetrates ethmoidal labyrinth to drain frontal sinus into middle meatus
Name the main openings in the bony skeleton of the nose
- Cribriform plate (olfaction)
- Sphenopalatine foramen
- Incisive foramen
- Foramen cecum
Describe the blood supply to the nose
- Many anastamoses
- Facial artery (superior labial a)
- Maxillary artery (sphenopalatine and greater palatine)
- Ophthalmic artery (Anterior and posterior ethmoidal)
What is kiesselbachs area (little’s area)?
- Area rich in anastamoses
- Common site of nose bleed
Why is it important the nasal caviry has a rich blood supply?
-Warm and humidify air
Describe the venous drainage of the nasal cavity
- Nasal vein (foramen cecum)-> saggital sinus
- Drainage into facial vein
- Drainage into cavernous sinus
- Drainage into pterygoid plexus
What is epistaxis?
-Nose bleed
What are the 2 most likely sites of a nose bleed? Which is most common?
- Anterior (kiesselbach’s area ~90%)
- Posterior (sphenopalatine artery)
In who do nose bleeds normally occur?
-Young children or older adults
Name 2 common septal problems and their causes
- Septal deviation -> congenital or aquired
- Nasal septum necrosis -> injury to septum
What is a saddle nose deformity?
-Nasal septum necrosis causes loss of skeletal support -> saddle nose
Describe the innervation of the nasal cavity
- Olfaction -> CN1 (special sensory)
- General sensory -> CNV1 and CNV2 (both inside and out)
What epithelium lines the nasal cavity?
- Pseudostratified columnar ciliated epithelium with goblet cells
- Olfactory cells with olfactory receptors
What are paranasal sinuses?
- Paired mucous membrane lined out-pockets of the nasal cavity which drain into the nasal cavity
- Maxillary, frontal, sphenoid and ethmoid
What is the fuction of the paranasal sinuses?
-Largely unknown
?reduce weight of skull
Why can sinusitis in the maxillary sinus cause toothache?
-Roots of first two molars are in very close proximity to maxillary sinus -> inflammation can lead to toothache
When does the maxillary sinus develop from?
- Present at birth
- Enlarges from 8 years onwards
Where does the maxillary sinus drain?
-Middle meatus
When does the frontal sinus develop from?
- Not present at birth
- Develops from 7 years onwards
Where does the frontal sinus drain and through what duct?
- Middle meatus
- Frontonasal duct
When does the sphenoid sinus develop from?
- Small at birth
- Enlarges after puberty
What structures is the frontal sinus in close proximity with?
- Anterior cranial fossa
- The orbit
What structures is the sphenoid sinus in close proximity to?
- Pituitary fossa/middle cranial fossa
- Cavernous sinus and ICA
- Posterior cranial fossa/pons
- Roof of nasopharynx
What is different about the ethmoid sinus?
-Made from air cells of Ethmoidal labyrinth of ethmoid bones between orbit and nasal cavity
Where do the anterior ethmoidal air cells drain and how?
-Middle meatus by infundibulum
Where do the middle ethmoidal air cells drain?
-Directly into middle meatus
Where do the posterior ethmoidal air cells drain?
-Superior meatus
Related to the nasal cavity, how can infection spread to the anterior cranial fossa?
- Saggital sinus (foramen cecum)
- Cavernous sinus
Related to the nasal cavity, how can infection spread to the middle ear?
-Eustachian tube
Related to the nasal cavity, how can infection spread to paranasal sinuses?
-Directly through meatus and ducts
Related to the nasal cavity, how can infection spread to the lacrimal apparatus and conjunctiva?
-Nasolacrimal duct
What are the functions of the nose?
- Olfaction
- Respirtation
- Filter and humidify
- Drain and eliminate paranasal sinus and nasolacrimal duct secretions
What is rhinitis?
-Inflammation of the nasal mucosa leading to swelling and increased volume of secretions
Give 3 causes of rhinitis
- Infective (viral)
- Allergic
- Nasal polyps
Are nasal polyps common?
-Yes
What is sinusitis? When is it defined as acute, sub-acute and chronic?
- Inflammation of the mucosal lining of the sinuses
- Acute = 7-30 days
- Sub acute -> 4 weeks - 12 weeks
- Chronic > 90 days
What are the most common causes of sinusitis?
- Viral infection with secondary bacterial infection
- S pneumoniae
- H influenzae
