Anatomy of paranasal air sinuses

Basic anatomy of Paranasal air sinuses described in a simple way with the aid of images.

1. Anatomy of Paranasal Air Sinuses Venkatesh Karthikeyan III MBBS Velammal Medical College Email : [email protected]

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

9. Drainage : Anterior part of hiatus semilunaris of middle meatus (through frontonasal duct)

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

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

12. 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

13. Largest of Paranasal sinuses Number : 2 Shape : Pyramidal Maxillary Sinus

14. Drainage : Posterior part of Hiatus semilunaris of the middle meatus

15. Vertical : 3.5 cm Transverse : 2.5 cm Antero-posterior : 3.25 cm Measurements

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

17. Base : Lateral wall of nose Apex : Zygomatic process of maxilla

18. 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)

19. 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

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

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

22. 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

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

24. Drainage : Sphenoethmoidal recess of nasal cavity

25. Vertical : 2 cm Transverse : 1.5 cm Anteroposterior : 2 cm Measurements

26. Above : Pituitary gland and optic chiasma Below : Roof of nasopharynx Relations

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

28. 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

29. Firing Round

30. Histology of Paranasal Sinus?

31. Base and Apex of Maxillary Sinus?

32. Superior Relation of Sphenoidal sinus?

33. Drainage of Frontal Sinus?

34. Who is he?

35. Thank you 