Anatomy and physiology of the nose and sinuses

Question 1

What are functions of the nose?

Answer 1

• Primary function is respiration
• Warming of inspired air
• Humidification
• Filtration of large particulate matter by hairs (vibrisae)
• Mucus production, trapping and clearance of small particulate matter
• Immune protection
• Olfaction
• Drainage/aeration of the middle ear via Eustachian tube
• Drainage of paranasal sinuses and nasolacrimal duct
• Voice modification
• Pheromone detection

Question 2

Describe the epithelium of the nose

Answer 2

Ciliated columnar epithelium with goblet cells

Question 3

What are the coarse hairs in the nasal vestibule called?

Answer 3

vibrisae

Question 4

What in the nose is responsible for pheromone detection?

Answer 4

Pheromone detection via the vomero-nasal organ of Jacobsen

Question 5

What are the functions of the sinuses?

Answer 5

• Help with vocal resonance
• Decrease the weight of skull and facial bones
• Act as buffer for trauma

Question 6

What makes up the internal nose?

Answer 6

Midline partition - nasal septum

Lateral walls
– Turbinates

Roof
– Cribiform plate of the ethmoid bone

Floor
– Hard palate

Associated structures
– Paranasal sinuses
– Nasopharynx

Question 7

What makes up the septum of the nose?

Answer 7

Made up of the:

• perpendicular plate of the ethmoid bone
• vomer bone
• septal nasal cartilage
• crest of the maxillary bone
• crest of the palatine bone

Question 8

What is a serious complication often associated with a deviation or perforation of the septum?

Answer 8

Septal haematoma

Question 9

What can result from the delayed treatment of a septal haematoma?

Answer 9

Saddle nose deformity - collapsed nose due to necrosis of tissue due to compression of blood supply by a haematoma

Question 10

What is the clinical significance of the nasal turbinates?

Answer 10

Clinical relevance – usually inferior turbinate only
Can cause nasal blockage due to
• Infection
• Inflammation e.g allergic rhinitis
Usually managed medically with topical steroid sprays
Can be managed surgically with turbinate reduction surgery
Can also become inflamed and cause nasal congestion, so are surgically removed

Question 11

List the paranasal sinuses

Answer 11

•	Frontal
•	Maxillary x 2
•	Ethmoid
–	Anterior and posterior
•	Sphenoid

Question 12

Describe the drainage pathways of the three meatuses of the nose

Answer 12

Inferior meatus
– Nasolacrimal duct

Middle meatus
– Frontal sinus
– Maxillary sinus
– Anterior ethmoid sinus

Superior meatus
– Posterior ethmoid sinus
– Sphenoid sinus

Question 13

Describe both acute and chronic rhinosinusitis

Answer 13

Rhinosinusitis – reflects a concurrent inflammatory and infective process that affects the nasal passageway and contiguous para-nasal sinuses

Acute (bacterial): lasts <12 weeks

Chronic: lasts  >12 weeks 
•	Allergic
•	Non allergic
–	With gelatinous polyps
–	Without polyps

Question 14

Describe some important anatomical relations of the sinuses

Answer 14

Frontal and ethmoid sinus
– Anterior cranial fossa

Maxillary sinus
– Orbits

Sphenoid sinus
– Optic nerve
– Internal carotid artery
– Cavernous sinus

Question 15

What is the importance of the neighbouring anatomical relations to the sinuses?

Answer 15

Spread of infections
– Meningitis
– Intracranial abscess’
– Orbital sepsis

Risks of surgery
– CSF leak
– Orbital complications - blindness

Question 16

Describe the nasopharynx

Answer 16

The nasopharynx is the upper part of the throat (pharynx) that lies behind the nose. It is a box-like chamber about 1½ inches on each edge. It lies just above the soft part of the roof of the mouth (soft palate) and just in back of the nasal passages

Question 17

Describe the blood supply of the nasopharynx

Answer 17

Anterior
– Derived from branches of internal carotid artery
• Ophthalmic artery, which branches into the anterior and posterior ethmoid arteries

Posterior
– Derived from branches of external carotid artery
• Sphenopalantine artery

Question 18

What is Little’s area?

Answer 18

Kiesselbach’s plexus, which lies in Kiesselbach’s area, Kiesselbach’s triangle, or Little’s area, is a region in the anteroinferior part of the nasal septum where four arteries anastomose to form a vascular plexus.

Question 19

What is the other name for Little’s area?

Answer 19

Kiesselbach’s plexus

Question 20

What is the clinical relevance of Little’s area?

Answer 20

Epistaxis: nose bleeds
– Most commonly occurs from Little’s area

Common causes
•	Trauma aka nose picking
•	Anticoagulants
•	Iatrogenic – surgery
•	Idiopathic
•	Hypertension

Question 21

What neural structure of the vertebrate forebrain is involved in olfaction?

Answer 21

The olfactory bulb (bulbus olfactorius) is a neural structure of the vertebrate forebrain involved in olfaction, the sense of smell.

Question 22

What nerve provides sensory innervation to the skin of the lower half of the nose and the septum?

Answer 22

The external nasal nerve (or external nasal branches) are terminal branches of the anterior ethmoidal nerves (from the ophthalmic division of the trigeminal nerve), and provide sensory innervation to the skin of the lower half of the nose and of the septum mobile nasi.