1. Paranasal Sinuses: Anatomy and Function
Dr. Jihan AL Maddah

2. Sinus Anatomy Overview
7 bones
4 paired sinuses
4 turbinates
3 meati
Drainage system
Nervous supply
Vascular supply
Related structures

3. Sinus
Development
Max: 1=newborn, 2=12 yrs, 3=adult sphenoid: 1=newborn, 2=3yo, 3=5yo, 4=7yo, 5=12yo, 6=adult, (7=presphenoid) frontal: 1=nasal septum, 2=middle nasal concha, 3=orbit, 4=newborn, 5=1yo, 6=4yo, 7=7yo, 8=12yo, 9=adult

4. Bony Structure Ethmoid Maxilla Palatine Lacrimal Pterygoid plate of
Sphenoid
Nasal
Inferior Turbinate

5. Arterial Supply External Carotid Internal Carotid Maxillary A.
Sphenopalatine
Internal Carotid
Ophthalmic A.
Ant. Ethmoid
Post. Ethmoid
Supraorbital
Supratrochlear

6. Innervation

7. Neurovascular Supply

8. Drainage
All sinus ostia drain into the nares at locations beneath the middle and superior turbinates.
The posterior ethmoid and sphenoid sinuses drain into the superior meatus below the superior turbinate.
Osteomeatal complex: The ostia of the maxillary, anterior ethmoid, and frontal sinuses share a common site of drainage within the middle meatus.
The common drainage pathway of the frontal, maxillary, and anterior ethmoid sinuses within the middle meatus allows relatively localized mucosal infection processes to promote infection in all these sinuses.

9. Osteomeatal Complex Middle meatus Maxillary Sinus Ostium
Anterior Ethmoid
Drainage

10. Sinus Drainage Schema

11. Anterior and posterior ethmoid sinuses are composed of multiple air cells separated by thin bony partitions. Each cell is drained by an independent ostium that measures only 1-2 mm in diameter.
The sphenoid sinuses sit immediately anterior to the pituitary fossa and just behind the posterior ethmoid.

12. Maxillary
Sinus

13. Frontal Sinus
Development
Frontal bone at birth
Age 5

14. Sphenoidal Sinus Development Arise within the nasal capsule (no pouch)
Age 3 begins to pneumatize

15. Sphenoid Sinus

16. Sphenoid Ostium
Sphenoethmoid Recess
Sphenoid Rostrum

17. Microscopic Anatomy Mucosa Goblet Cells Basement membrane
Cilliated columnar epithelial cells
Noncilliated columnar cells
Basal cells
Goblet Cells
Glycoproteins—viscosity and elasticity
Basement membrane
Submucosal glands

18. Microscopic Anatomy

19. Mucous Blanket Two layers Function Superficial layer Sol layer
Superficial layer traps bacteria and particulate matter.
Enzymes, antibodies, immune cells

20. Mucociliary Transport
Directional Flow of Mucous
Toward the choanae
Ostium drainage

21. Function of Paranasal Sinuses
Humidifying and warming inspired air
Regulation of intranasal pressure
Increasing surface area for olfaction
Lightening the skull
Resonance
Absorbing shock
Contribute to facial growth