Functions of the Nose?
- Airway for respiration
- Warming & Humidifying air
- Filtering out large particles
- Immune function
- Drains paranasal sinuses & nasolacrimal duct
- Drains/aerates middle ear via eustachian tube
- Voice Modification
- Pheromone Detection via Vomeronasal organ (of Jacobson) (in animals)
Who is most in need of the nose for respiration?
Neonates, they are obligate nasal breathers.
Describe the epithelium of the nasal cavity?
The sinonasal mucosa is the same as most of the resp. tract.
Ciliated Pseudostratified Columnar Epithelium with Goblet Cells
How does the nose filter out particles?
Coarse hairs (Vibrisae) in the nasal vestibule catch large particles. Smaller ones are caught in mucous and cleared by the cilia
What is the eustachian tube?
Connects nasopharynx and middle ear, to aerate/equalise pressure in the middle ear.
Normally its closed but opens on positive pressure or swallowing
What is the nasolacrimal duct?
Carries excess tears from the lacrimal sac to the nasal cavity.
The reason your nose runs when you cry or you can taste eyedrops.
Also known as tear duct
What is the function of sinuses?
Debated but we think:
- Help with vocal resonance
- Decrease weight of skull bones
- Buffer for Trauma
What are the sections of the external nose? (Locate on self)
Glabella Nasion Dorsum Supratip Tip Collumnella
What are the bony sections of the external nose?
The frontal process of the maxilla and the nasal bones.
What are the borders of the internal nose?
Midline - Nasal Septum
Laterally - Turbinates
Roof - Cribriform plate of ethmoid bone
Floor - Hard palate (maxilla and palatine bones)
What structures are associated with the internal nose?
The paranasal sinuses
What is a turbinate?
A bony scroll like projection from the internal lateral wall of the nose. There are 3: - Sup - Middle - Inf
Each is associated with its respective meatus which drains the sinuses
What are the clinical relevancies of the inner nose?
- Septal deviation
- Septal perforation
- Septal haematoma
- Nasal blockage due to inflamed turbinates
How does a septal perforation occur?
Pressure on the blood supply to the septum due to infection, trauma etc.
This leads to necrosis and break down of cartilage leading to perforation.
How would we treat inflamed turbinates?
Topical steroid treatment
Or Turbinate reduction surgery
List the sinuses in the face?
What is drained through the inferior meatus?
Excess tears from the eye (lacrimal sac) along the nasolacrimal.
What is drained by the middle meatus?
- Frontal Sinuses
- Maxillarly Sinuses
- Anterior Ethmoid Sinus
- Middle Ethmoid Sinus
What is drained by the superior meatus?
- Posterior Ethmoid sinus
clinical relevance of the sinuses?
- Concurrent inflammation and infection of the nasal passage and paranasal sinuses.
- Acutely its probably bacterial
- Chronic it may be allergic or non-allergic
- Non-allergic comes with or without polyps
What are the anatomical relations of the frontal/ethmoid sinuses?
Anterior Cranial Fossa
What are the anatomical relations of the maxillary sinus?
What are the anatomical relations of the sphenoid sinus?
- Optic Nerve
- Cavernous Sinus
What are the clinical relevance of the sinuse’s anatomical relations?
Spread of infection E.g.:
- Intracranial Abscess
- Orbital Sepsis
Risks from surgery E.g.:
- Orbital complications from sinus surgery
Explain the nasal blood supply?
Anterior of the nose:
ICA -> Opthalmic Art -> Ant/Post Ethmoid Art.
Posterior of the nose:
ECA -> Maxillary -> sphenopalatine
Whats the clinical relevance of the nasal blood supply?
(acute haemorrhage from the nose)
Usually occurs in little’s area (anterior of nasal cavity)
- Iatrogenic (surgery)
Explain the nervous innervation of the nose?
Most of the nasal cavity is supplied by the pterygopalatine ganglion at the back of the cavity.
It in turn is mainly facial nerve with some maxillary (Trigeminal V2) involvement…
The olfactory bulb inserts fibres through the roof of the nasal cavity and inserts directly into the forebrain.
Clinical relevance of the nose nerves?
Olfactory dysfunction can occur due to rhinosinusitis, post-viral anosmia (loss of smell) or trauma.
What drains the sphenoid sinus?
The spheno-ethmoid recess