Nose and Paranasal sinuses Flashcards
What are the functions of the nose?
Olfaction (smell)
Respiration
Filter and humidify
Drain & eliminate paranasal sinus and nasolacrimal duct secretions
Briefly describe the external nose.
Provides opening into nasal cavity
Bony and (predominantly) cartilaginous components
Nostrils bounded laterally by alae
Skin covering nose extends into the vestibule
List the bones that constitute the external nose.
Nasal bone
Frontal process of maxilla
(Lacrimal bone?)
List the cartilage of the external nose.
Septal cartilage - Lateral process of septal cartilage - Superior margin of septal cartilage Major alar cartilage Minor alar cartilage
What is the most common facial fracture?
Nasal fracture
Tell me a little bit about nasal fractures.
Most common facial fracture
History of force to the face
Deformity
Complications include septal haematoma
What are the openings to the nasal cavity called?
Nares
What are the passage ways from the nasal cavity to the nasopharynx called?
Choanae
What bones contribute to the skeleton of the nose?
Frontal Nasal Ethmoid (plus its perpendicular plate) Sphenoid Vomer Palatine process of maxilla Horizontal process of palatine bone Inferior concha
What are the lateral walls of the nasal cavity?
Conchae (a.k.a. turbinates) (creates 5 passages within cavity - 1 unpaired and 3 paired) (made from ethmoid bone) Openings into the nasal cavity - Draining - Sinuses - Lacrimal apparatus - Middle ear
What are on the medial walls (septum) of the nasal cavity?
Bony part - ethmoid bone
Cartilaginous part
What re the passages of the naval cavity called?
Sphenoidal recess
Superior meatus
Middle meatus
Inferior meatus
Describe the ethmoidal bone.
It has a perpendicular plate in the centre with a cribriform plate at the top
Cribriform plate has lots of holes - for olfaction
Two Ethmoidal labyrinths (air cells) joined by the cribriform plate
The cribriform plate has the crista galli on top
Crista galli anchors falx cerebri
Infundibulum - a groove penetrating ethmoidal labyrinth and drains frontal sinus
What are the openings inside the nasal cavity?
Cribriform plate - olfaction
Sphenopalatine foramen
Incisive foramen - nerve and artery exchange (to mouth)
Foramen cecum - nasal veins to superior sagittal sinus
(some individuals)
Give an overview of the blood supply of the nasal cavity.
Facial artery (external carotid artery) - Brachial superior labial artery Maxillary artery (external carotid artery) - Sphenopalatine artery - Greater palatine artery Ophthalmic artery (internal carotid artery) - Anterior ethmoidal artery - Posterior ethmoidal artery
What is the clinical significance to nasal blood supply?
An area of anastomoses:
- Kiesselbach’s plexus - (a.k.a. Little’s area)
So any damage can lead to epistaxis (nose bleed)
Give an overview of the venous drainage of the nasal cavity
Drains to:
- Cavernous sinus
- Facial vein
- Pterygoid plexus
Name some deformities of the nose and nasal cavity.
Nasal septum deviation - Congenital / acquired - Narrowing / obstruction Nasal septum necrosis - Injury to nasal septum - Saddle nose deformity
Give an overview of the innervation of the nasal cavity.
Special sensory innervation
- CN I: Olfactory Nerve
General sensory innervation to septum and lateral walls
- Ophthalmic (CN V1) and Maxillary (CN V2)
Posterior inferior of nasal cavity
- Maxillary nerve
- Nasopalatine nerve (septum) & branches greater
palatine nerve to lateral wall
Anterior superior of nasal cavity
- Ophthalmic nerve
- Branches of nasociliary nerve
Give an overview of the innervation of the external nose.
Infraorbital nerve (CN V2) External nasal nerve (CN V1)
What is the epithelium of the respiratory region of the nasal cavity?
Pseudostratified columnar ciliated, with goblet cells
What is the epithelium of the olfactory region of the nasal cavity?
Olfactory cells with olfactory receptors
What are the paranasal sinuses?
Paired, mucous membrane lined out-pocketings of the nasal cavity, draining into the nasal cavity
Maxillary
Frontal
Sphenoid
Ethmoid
What is the function of the paranasal sinuses?
Unknown
May contribute to conditioning of inspired air
Reduce weight of skull
Describe the maxillary sinus.
Roof = floor of orbit Floor = alveolar part of maxilla Posteriorly = pterygopalatine & infratemporal fossae
Present at birth, enlarging from about 8yrs
Opens into middle meatus
Describe the frontal sinus.
Not present at birth
Variable in size
Related to anterior cranial fossa and the orbit
Drains into the middle meatus through the frontonasal duct
Describe the sphenoid sinus
Small at birth, enlarging after puberty
Related to:
- Pituitary fossa & middle cranial fossa
- Cavernous sinus and inferior carotid artery
- Posterior cranial fossa & pons
- Roof of nasopharynx
Describe the ethmoidal sinus.
Ethmoid air cells between orbit and nasal cavity
Anterior cells - Middle meatus via infundibulum Middle cells - Bulla - Directly into middle meatus Posterior cells - Superior meatus
What is the clinical importance of the nasal cavities and the spread of infection?
Infection can spread to:
- Anterior cranial fossa
- Middle ear
- Paranasal sinuses
- Lacrimal apparatus & conjunctiva
What is rhinitis?
Inflammation of the nasal mucosa - Leading to swelling & increased volume of secretion Causes include: - Infective (viral) - Allergic - Nasal polyps
Tell me abut nasal polyps.
Prevalence ~2-4%
Might be linked to chronic rhinosinusitis
Grow close to the ostiomeatal complex of the nasopharynx
Nasal obstruction
- Snoring/obstructive sleep apnoea
What is sinusitis?
Inflammation of the mucosal lining of the sinuses
Acute: 7 - 30 days
Sub-acute: 4-12 weeks
Chronic: >90 days
Infection
- Viral with secondary bacterial infection
- S pneumonia & H influenzae
