This document provides information about the paranasal sinuses. It discusses the embryology, classification, anatomy and histology of the different paranasal sinuses including the frontal sinus, maxillary sinus, ethmoidal sinuses and sphenoidal sinus. For each sinus, it describes the measurements, relations, arterial supply, venous drainage, lymphatic drainage and nerve supply. The document appears to be notes for a medical student on the topic of paranasal sinuses.

1. Venkatesh Karthikeyan
III MBBS
Velammal Medical College
Email : 4852012@gmail.com

2. 
 They are air containing cavities in the bones around
the nasal cavity.
 Embryology – Develop as mucosal diverticula of
main nasal cavity, invading the adjacent bones.
What are they?

3. 
Histology

4. 
 Makes skull lighter
 Adds resonance to voice
 Acts as air conditioning chamber by adding
humidity and temperature to inspired air
 Aids in growth of facial skeleton after birth.
Why it is important?

5. 
The Paranasal Sinuses

6. 
Relation to Orbit

7. 
 Anterior group (draining into middle meatus)
 Frontal sinus
 Maxillary sinus
 Anterior and middle ethmoidal sinus
 Posterior group (not draining into middle meatus)
 Posterior ethmoidal sinus
 Sphenoidal sinus
Classification of PNS

8. 

9. 
 Number : 2
 Shape : Triangular
 Lies between outer and inner tables of frontal bone
Frontal Air Sinus

10. 
 Drainage : Anterior part of hiatus semilunaris of
middle meatus (through frontonasal duct)

11. 
 Vertical : 3 cm
 Transverse : 2.5 mm
 Antero- posterior : 1.8 cm
Measurements

12. 
 Anterior wall – Superciliary
arch of forehead
 Posterior wall – Meninges
and Frontal lobe
 Inferior wall – Roof of nose
and orbit, ethmoidal air cells
Relations

13. 
 Arterial supply : Supraorbital artery ( Ophthalmic
artery Internal Carotid artery)
 Venous drainage : Supraorbital vein and Superior
ophthalmic vein
 Lymphatic drainage : Submandibular nodes
 Nerve supply : Supraorbital nerve

14. 
 Largest of Paranasal sinuses
 Number : 2
 Shape : Pyramidal
Maxillary Sinus

15. 
 Drainage : Posterior part of Hiatus semilunaris of the
middle meatus

16. 
 Vertical : 3.5 cm
 Transverse : 2.5 cm
 Antero-posterior : 3.25 cm
Measurements

17. 
 Roof : Floor of orbit.
Traversed by infraorbital
nerve and artery
 Floor : Alveolar process of
nose
Relations

18. 
 Base : Lateral wall of nose
 Apex : Zygomatic process of maxilla

19. 
 Anterior wall : Anterior
surface of body of
maxilla(Anterior superior
alveolar nerve runs in a
curved bony canal called
canalis sinuosus)
 Posterior wall :
Infratemporal surface of
maxilla (pierced by
posterior superior alveolar
nerves and vessels)

20. 
 Arterial Supply : Facial, infraorbital and greater
palatine arteries
 Venous drainage : Facial vein and pterygoid venous
plexus
 Lymphatic drainage : Submandibular nerves
 Nerve supply : Anterior, Middle and Posterior
Superior alveolar nerve

21. 
 Three groups:
 Anterior : upto 11 cells
 Middle : 1-3 cells
 Posterior : 1-7 cells
Ethmoidal air sinus

22. 
 Drainage :
 Anterior group  Hiatus semilunaris
 Middle group  Middle on surface of Bulla ethmoidalis
 Posterior group  Posterior part of superior meatus

23.  Anterior ethmoidal sinus:
 Supplied by anterior ethmoidal nerves and vessels
 Lymphatics : Submandibular nodes
 Middle ethmoidal sinus :
 Supplied by anterior ethmoidal nerves and vessels and orbital
branches of pterygopalatine ganglion
 Lymphatics : Submandibular nodes
 Posterior ethmoidal sinus :
 Supplied by posterior ethmoidal nerves and vessels and orbital
branches of pterygopalatine ganglion
 Lymphatics : Retropharyngeal nodes

24. 
 Within body of sphenoid
bone above and behind nasal
cavity.
 Separated by bony septum.
Sphenoidal Sinuses

25. 
Drainage : Sphenoethmoidal recess of nasal
cavity

26. 
 Vertical : 2 cm
 Transverse : 1.5 cm
 Anteroposterior : 2 cm
Measurements

27.  Above : Pituitary gland and optic
chiasma
 Below : Roof of nasopharynx
Relations

28.  Lateral : Cavernous sinus and Internal carotid artery
 Behind : Pons and Medulla oblangata
 In front : Sphenoethmoidal recess

29. 
 Arterial supply : Posterior ethmoidal and internal carotid
artery
 Venous drainage : Into pterygoid venous plexus and
cavernous sinus
 Lymphatics : Retropharyngeal node
 Nerve supply : Posterior ethmoidal nerve and orbital
branches of pterygopalatine ganglion

30. 
Firing Round

31. 
Histology of Paranasal
Sinus?

32. 
Base and Apex of
Maxillary Sinus?

33. 
Superior Relation of
Sphenoidal sinus?

34. 
Drainage of Frontal
Sinus?

35. 
Who is he?

36. 
Thank you 