The Nose and Paranasal Sinuses

Question 1

List the bones that contribute to the skeleton of the nose

Answer 1

Frontal
Nasal
Vomer
Ethmoid
Sphenoid
Maxilla
Palatine
(+ cartilage - lateral x2, alar x2, septal)

Question 2

Describe the neurovascular structures that supply the nose

Answer 2

Blood supply:
Facial artery (ECA) –> superior labial
Maxillary artery (ECA) –> sphenopalatine, greater palatine
Ophthalmic artery (ICA) –> anterior ethmoidal, posterior ethmoidal
Venous drainage:
Cavernous sinus
Facial vein
Pterygoid plexus
Innervation:
Special sensory - CN I
General sensory - ophthalmic and maxillary division of CN V

Question 3

Describe some cases of common disorders and pathologies affecting the nose

Answer 3

Fracture - force to face –> deformity, complications including septal haematoma
Epistaxis - in Little/Kisselbach’s area, rich anastamoses of five arteries, local or systemic, anterior or posterior
Nasal septum deviation - congenital/acquired, narrowing/obstruction
Nasal septum necrosis –> saddle nose deformity
Rhinitis - inflammation of nasal mucosa (infective, allergic) –> swelling, increased secretion
Nasal polyps
Cribiform plate fracture –> anosmia,mCSF rhinorrhea, meningitis risk as infection may spread to anterior cranial fossa (therefore give prophylactic antibiotics)

Question 4

What are paranasal sinuses?

Answer 4

Paired, mucous membrane lined out pocketings of the nasal cavity

Question 5

Describe some of the functions of paranasal sinuses

Answer 5

Conditioning of inspired air
Reduce weight of skull
Buffer for trauma
Regular intranasal pressure
Increase voice resonance

Question 6

Describe the anatomy of the maxillary sinus

Answer 6

Largest sinus
Roof - floor of orbit
Floor - alveolar part of maxilla, 1+2 molar teeth
Posteriorly - pterygopalatine and infratemporal fossae
Opens into middle nasal meatus via semilunar hiatus
Present at birth, enlarged from 8yrs
Innervated by CN V2

Question 7

Describe the anatomy of the frontal sinus

Answer 7

Not present at birth 
Variable in size
Drains into middle nasal meatus via frontonasal duct --> ethmoidal infundibulum --> semilunar hiatus 
Inferiorly - orbits
Posteriorly - anterior cranial fossa 
Innervated by CN V1

Question 8

Describe the anatomy of the sphenoidal sinus

Answer 8

S,all at birth, enlarges after puberty 
Extensive formation of air cells 
Related to - pituitary fossa (transsphenoidal pituitary surgery), Middle cranial fossa, cavernous sinus, ICA, posterior cranial fossa, pons, roof of nasopharynx 
Drains into sphenoethmoidal recess
Innervated by CN V1

Question 9

Describe the anatomy of the ethmoidal sinus

Answer 9

Between nasal cavity and orbit
Anterior cells drain into middle nasal meatus via infundibulum
Middle cells drain directly into middle nasal meatus
Posterior cells drain directly into superior nasal meatus
Superiorly - cribiform plate
Laterally - lamina papyracea (orbit medial wall)
Innervated by CN V1

Question 10

Describe some cases of common disorders and pathologies affecting the paranasal sinuses

Answer 10

Sinusitis - inflammation of the mucosal lining of the sinuses. Acute - 7-30 days, sub acute - 4-12 weeks, chronic >90 days. Infection can be viral or bacterial, usually same causative agents at URTI (s pneumoniae, h influenzae)
Meningitis - infection spreading through anterior cranial fossa

Question 11

List some of the causes of epistaxis

Answer 11

Trauma
Infection
NSAIDs
Vascular abnormalities
Coagulation defect
Tumour
Mucosal drying

Question 12

Describe the stepwise approach in the management of epistaxis

Answer 12

1. IV fluid, resuscitation, FBC, clotting factors, renal tests
2. Hippocratic method - 10 mins
3. ICE - nasoconstriction
4. Cautery - silver nitrate, electro (with anaesthetic)
5. ‘Nasal Tampons’ - merocel, rapid rhino, entered horizontally, put in rapidly –> pushes against turbinates to attempt to stop bleeding
6. Posterior packing - horizontally layered gauze packing saturated with mupirocin ointment, foley ballon in posterior choana (back of oropharynx)
7. Surgical intervention - ligation of branches (sphenopalatine, maxillary, external carotid), radiological embolisation

Question 13

Describe the function of the nose and nasal cavity

Answer 13

Olfaction
Filter, humidify and warm air
Respiration
Drain and eliminate paranasal sinus and nasolacrimal duct secretions

Question 14

What arteries form Little’s area?

Answer 14

Greater palatine (ECA)
Anterior ethmoidal (ICA)
Superior labial (ECA)
Posterior ethmoidal (ICA)
Sphenopalatine (ECA)