10) Anatomy of Nose Flashcards
What are the functions of the nose?
Sense of smell Route for inspired air Filters air (removes particles by trapping in nasal hair or mucus) Moistens and warms air Resonating chamber for speech
What gives the external nose shape?
Hyaline cartilage (located anteriorly)
Describe the features of the external nose:
Root (top)
Bridge (below root)
Tip/apex
What bones form the root of the nose?
Nasal bone and frontal process of maxilla
What is the nose susceptible to and why?
Fractures and septal deviation due to prominent position
Where does the nasal cavity run?
Nostrils to posterior nasal aperture (choana)
What is posterior to the nasal cavity?
Nasopharynx and Eustachian tube
What forms the lateral wall of the nasal cavity?
Maxilla and inferior concha
What forms the medial wall of the nasal cavity?
Septal cartilage, perpendicular plate of ethmoid and vomer
What forms the floor of the nasal cavity?
Hard palate (maxilla and palatine) and soft palate
What forms the roof of the nasal cavity?
Nasal, frontal, ethmoid and sphenoid
What is the path of CSF in CSF rhinorrhoea?
Crista gala perforates meninges, CSF leaks through cribriform plate
What is a septal haematoma?
Trauma to nose leads to buckling of septum and shearing of BVs causing blood to accumulate between perichondrium and cartilage
What can occur if a septal haematoma is left untreated?
Avascular necrosis of cartilaginous septum and saddling of nasal dorsum
Also, infection leading to septal abscess
What is the function of the concha on the lateral wall of nasal cavity?
Slow airflow and increase SA for humidification and warming of air
What is the relevance of the spheno-ethmoidal recess?
Where some sinuses drain into nasal cavity
What is the majority of epithelium of nasal cavity?
Pseudostratified columnar ciliated epithelium
Where does the nasolacrimal duct drain into the nasal cavity?
Inferior meatus
How does the epithelium of the nasal cavity carry out functions of the nose?
Filters - mucus and cilia
Warms - rich blood supply
Humidifies - watery secretions
What are nasal polyps?
Fleshy, benign swellings arising from nasal mucosa, usually both sides
Greater than 40 years
What are the symptoms of nasal polyps?
Blocked nose
Watery rhinorrhoea
Post nasal drip
Decreased smell and taste
How does a nasal tumour present?
Unilateral polyp with blood tinged secretion
What is rhinitis?
Inflamm of nasal mucosa lining
What are the symptoms of rhinitis?
Nasal congestion Rhinorrhoea Sneezing Irritation Post nasal drip
What are the causes of rhinitis?
Acute infective rhinitis, allergic rhinitis
Describe the blood supply to the nasal cavity:
Branches of ophthalmic artery (ICA) - ant and pos ethmoidal
Branch of maxillary artery (ECA) - sphenopalantine (posterior septum)
What is the clinical relevance of Kiesselbach’s area?
Where anastomoses occur, 90% of nose bleeds from here
Why are nose bleeds from sphenopalantine artery worse?
Hard to stop as posterior and blood is at higher pressure
What is the venous drainage of the nasal cavity?
Cavernous sinus, facial vein and pterygoid plexus
Name the paranasal sinuses:
Frontal, ethmoid, sphenoid and maxillary
What are the paranasal sinuses?
Air filled spaces lined with respiratory mucosa
What is the function of the paranasal sinuses?
Help humidify and warm air, lighten skull
How do the sinuses drain into the nasal cavity?
Via ostia, most into middle meatus
What can cause sinusitis?
Where is it most likely?
Infections spreading from nasal cavity
Obstruction of drainage
Maxillary Sinus
What are some important anatomical relations to the sinuses?
Orbit and anterior cranial fossa (frontal and ethmoidal)
Roots of upper teeth (maxillary)
What is acute sinusitis?
Acute inflammation of lining of sinus lasting less than 4 weeks
Commonly infective or secondary to cold
Describe the pathophysiology of acute sinusitis:
Infection leads to reduced ciliary function, mucosal oedema and increased nasal secretions. This impedes drainage and stagnant secretions are breeding ground for bacteria
What are the symptoms of acute sinusitis?
Non-resolving cold
Pyrexia
Rhinorrhoea with discharge
Headache/facial pain in area of sinus (worse leaning forward)
What conditions can increase the risk of sinusitis?
Conditions blocking ostia e.g. polyps or deviated septum
Dental infection
What is the treatment for sinusitis?
Self limiting, but may need antibiotics
What is a complication of sinusitis?
Orbital cellulitis
What is the nerve supply to the nasal cavity and sinuses?
Antero-superior part of cavity and most sinuses - ophthalmic nerve (CN Va)
Postero-inferior part and maxillary sinus - maxillary nerve (CN Vb)
What is epistaxis and how can it be self-treated?
Nose bleed, pinch nose in front of bony bridge
What can cause nose bleeds?
Spontaneous, minor trauma, abnormal coagulation or CT disorders
What is the treatment for nose bleeds if compression fails?
Cauterise
Anterior packing or nasal tampons
Posterior packing
Surgery e.g. ligation
