Nose

Question 0

Describe the features of the nose

Answer 0

External nose:

• boney prominence (nasal, maxilla frontal process and frontal bone)
• cartilaginous portion (2 lateral, 2 alar and 1 septal cartilage)

Nasal septum:

• anterior is cartilage
• middle is perpendicular plate of ethmoid bone
• posterior is vomer
• inferior is hard palate of palatine and maxilla bones (separate nasal and oral cavities)

Question 1

Briefly describe the function of the nose

Answer 1

Olfaction
Respiratory: warm, filter and humidify air
Drain paranasal sinuses and naso lacrimal duct

Question 2

Discuss abnormalities of the nose

Answer 2

Nasal fracture: common due to position, can lead to septal haematoma
Nasal septum deviation: birth/trauma can lead to nasal obstruction
Nasal septum necrosis: loss of blood supply to cartilage can lead to saddle nose deformity

Question 3

What structures form/found within the nasal cavity?

Answer 3

Nostrils: openings
Conchae: (turbinates) superior, middle and inferior to increase surface air
- inferior is longest and is an independent bone
- superior and middle are derived from ethmoid bone
- inferior, middle and superior nasal meatus lie beneath

The nasal cavity is lined with nasal mucosa, except the vestibule which is lined with skin

Houses sphenoethmoidal recess, modified mucous membrane containing olfactory cells. Atonal processes project through the cribriform plate to the olfactory bulb

Question 4

What are the opening within the nasal cavity?

Answer 4

Cribriform plate: CN I olfaction
Sphenopalatine foramen: Sphenopalatine artery
Incisive foramen: arterial blood supply
Foramen cecum: nasal vein drainage

Question 5

What is the blood supply to the nose and why is it important?

Answer 5

ICA: Opthalmic artery to anterior/posterior ethmoidal arteries
ECA: maxillary artery to Sphenopalatine and greater palatine arteries
ECA: facial artery to superior labial artery

Kesselbachs (Littles) area is an area of anastomoses to the anterior septum, rupture is associated with 90% of all epistaxises
If the Sphenopalatine artery ruptures then this is associated with a posterior epistaxis

Venous drainage occurs via sub mucosal venous plexus, draining Ito the cavernous sinus, facial vein and pterygoid plexus

Question 6

What is the innervation to the nose?

Answer 6

Smell
- olfactory nerve CN I

General sensory posterior/inferior nasal mucosa
- nasopalatine nerve (CN V2-maxillary)

General sensory anterior/superior nasal mucosa
- anterior/posterior ethmoidal nerves (CN V1-Opthalmic)

General sensory external nose

• external nasal nerve CN V1
• infra orbital nerve CN V2

Question 7

What are the paranasal sinuses?

Answer 7

• paired air filled spaces (respiratory origin)
• 4 sinuses
  A) Frontal:
• in frontal bone detectable from 7yrs
• drain into frontonasal duct, ethmoid infundibulum to middle nasal recess/meatus

B) Ethmoidal:

• invaginations of middle/superior nasal recesses (visible from 2yrs)
• anterior ethmoidal: drains via infundibulum to middle nasal recess
• middle ethmoidal: drains direct to middle nasal recess
• posterior ethmoidal: drains direct to superior nasal recess

C) Sphenoidal:

• found in body of sphenoid bone, small at birth but grow
• drain into sphenoethmoidal recess

D) Maxillary:
- largest, drain via maxillary Ostium to middle nasal recess

Question 8

Why is it important to know about the the nose and it’s contents?

Answer 8

To allow consideration to the spread of infection…to

• anterior cranial fossa via cribriform plate
• paranasal sinuses via their openings
• lacrimal apparatus and conjunctiva via nasolacrimal duct
• middle ear via Eustachian tube

Question 9

Discuss the problems associated with the nose.

Answer 9

Rhinitis: inflamed nasal mucosa and increased secretions, of infective, allergic or nasal polyp origin

Nasal polyps: growth of osteomeatal complex causing obstruction

Sinusitis: inflamed sinus mucosa (acute: 7-30 days, sub acute: 4-12/52, chronic: >3/12)

Ethmoidal sinus infection: may break through medial wall of orbit and affect Opthalmic artery and CN II causing visual problems

Maxillary sinus infection: common, sinus can drain if full when laid on side

Maxillary teeth: 3 maxillary molars near maxillary floor, can become infected if the bone is fractured or toothache can occur if the nerves supplying them (superior alveolar nerves CN V2) irritated