Paranasal Sinuses - Regional Anatomy

Question 1

What age do the frontal and sphenoid become visible on a radiograph

Answer 1

6/7 years of age

Question 2

What sinus develops last

Answer 2

Ethmoid

Question 3

What is it lined by

Answer 3

Nasal mucous membrane e.g. ciliated columnar epithelium

Question 4

What are the paranasal sinuses?

Answer 4

1. Maxillary (2) - maxillary (facial) bones
2. Frontal (2) - frontal (cranial) bones
3. Ethmoid (many) - ethmoid (cranial) bones
4. Sphenoid (cranial) bones

Question 5

Maxillary sinus

Answer 5

• frontal view - pyramidal shaped
• anteriorly - bounded by facial surface of maxilla
• posteriorly - related to pterygopalatine fossa
• opening of maxillary sinus is into nasal cavity between inferior and middle conchae

Question 6

Maxillary sinus complications?

Answer 6

Complications:
• Walls of the maxilla are very thin
• They are usually paired and fairly symmetric in size and shape
• Complications can occur when extracting molars
• Oral Antral Fistula can occur
• Infection called sinusitis occurs

Question 7

Frontal sinuses

Answer 7

• occupy frontal bone above superior surface of orbit, posterior to the glabella
• rarely become aerated before age 6
• rarely symmetric
• separated by a septum

Question 8

Ethmoid sinus

Answer 8

• contained within the lateral masses or labyrinths of the ethmoid bone
• these air cells are grouped into anterior, middle and posterior collections but they all intercommunicate
• side view -anterior ethmoid sinuses appear to fill the orbits - because portions of the ethmoid sinuses are contained in the lateral masses of the ethmoid bone, which helps form the medial wall of each orbit

Question 9

Sphenoid sinus

Answer 9

• lies in body of the sphenoid bone directly below the sella turcica
• body of sphenoid containing these is cubic and frequently divided by a thin septum to form two cavities - septum may be incomplete or absent entirely, however, resulting in only one cavity

Question 10

Functions of paranasal sinuses

Answer 10

• Aid in cleaning nasal passages
• Providing resonance to voice
• Warming and moistening air
• Reducing total weight of head
• Insulating brain from temperature extremes

Question 11

Lymphatic Drainage - where does the lateral wall of the nose drain into

Answer 11

Submandibular nodes

Question 12

Lymphatic Drainage - where does the posterior part of the nasal cavity drain into

Answer 12

Retropharangeal and upper deep cervical lymph nodes

Question 13

Nerve supply - frontal

Answer 13

Supplied by supraorbital nerve from ophthalmic from ophthalmic division of the trigeminal

Question 14

Nerve supply - sphenoidal and ethmoidal

Answer 14

Supplied by ethmoidal branches of maxillary division of the trigeminal nerve

Question 15

Nerve supply - maxillary

Answer 15

Supplied by branches of superior alveolar and infraorbital nerves from maxillary division of trigeminal nerve

Question 16

Blood supply - maxillary and ethmoidal sinuses

Answer 16

supplied by sphenopalatine or nasal artery (terminal branch of maxillary artery)

Question 17

Blood supply - sphenoidal, frontal and ethmoidal

Answer 17

supplied by anterior and posterior ethmoidal branches of opthalmic artery

Question 18

Blood supply

Answer 18

Branches of anterior middle and posterior superior
alveolar arteries also help to supply maxillary sinus