Paranasal sinuses are a group of air containing spaces that surround the nasal cavity and directly open into the nasal cavity through their ostia. Lined by pseudo stratified columnar epithelium

1. ANATOMY
OF
PARANASAL
SINUSES
By Ramagopalan

2. INTRODUCTION:
• Paranasal sinuses are a group of air containing
spaces that surround the nasal cavity and directly
open into the nasal cavity through their ostia.
• Lined by pseudostratified columnar epithelium

3. DEVELOPMENT:
Sinuses develop as small diverticula from the
nasal capsule which invade the surrounding
bones of the skull. Only the frontal sinus is
absent at birth and most of the sinuses are fully
developed by puberty.
• Maxillary and ethmoid sinuses are
present at birth
• Sphenoid sinus is rudimentary at birth
• Frontal sinus is recognizable at 6 years of
age.

4. DIVISION:
Paranasal
sinuses
Anterior group:
• Frontal
• Anterior ethmoidal
• Maxillary air sinus
Posterior group:
• Posterior ethmoidal
• Sphenoidal air sinus

5. MAXILLARY SINUS:
• Also called Antrum of high more
• First appears at the 14 to 16th week of
gestation
• Largest sinus
Dimensions:
• Pyramidal in shape
• Apex towards zygomatic process
• height is 33 mm, width is 23 mm,
AP is 34 mm
• Capacity varies from 15 to 30 ml

6. MAXILLARY SINUS:
Roof:
• By floor of orbit
• Traversed by infraorbital canal
Floor:
• Lies 1.25 cm below the nasal floor
• By alveolar & palatine process of the
maxilla
• Related to the roots of the teeth

7. MAXILLARY SINUS:
Anterolateral wall:
• By facial surface of maxilla
• corresponds with canine fossa
Posterior wall:
• Pterygopalatine fossa
• Internal maxillary artery,
sphenopalatine ganglion, greater
palatine nerve( vidian nerve)

8. Median or nasal wall:
• From above: Uncinate
process, descending part
of lacrima bone
• From below: inferior
turbinate
• From behind:
perpendicular plate of
palatine bone
MAXILLARY SINUS:

9. MAXILLARY SINUS:
Arterial supply:
• Maxillary, facial, infraorbital and greater palatine arteries
Venous drainage:
• Anterior facial vein & pterygoid venous plexus
Lymphatics drainage:
• Submandibular lymph nodes

10. FRONTAL SINUS:
• Paired sinuses and separated by
intervening bony septum
• Posterior to the superciliary arches
• Between the outer and inner tables
Dimensions:
• Two parts : vertical and horizontal
• Like a pyramidal
• height is 31.6 mm, breadth is 25.8 mm,
depth is 18 mm
• Capacity varies from 15 to 30 ml

11. FRONTAL SINUS:
Anterior wall:
• By outer table of frontal bone
Posterior wall:
• Thin
• By inner table of frontal bone
• Separates the sinus from anterior
cranial fossa
Medial wall:
• Septum and anterior ethmoidal sinus

12. Floor:
• Orbital cavity and its contents
• Slopes towards the opening of
frontonasal duct
Extensions:
• Superiorly – between inner and
outer tables of frontal
FRONTAL SINUS:

13. FRONTAL SINUS:
Arterial supply:
• Supraorbital artery
• Anterior ethmoidal arteries
Venous drainage:
• Supraorbital vein
• Superior ophthalmic vein
Lymphatics drainage:
• Submandibular lymph nodes

14. ETHMOIDAL SINUSES:
• The ethmoid sinuses are the most
variable of the sinuses and develop from
pneumatization of the ethmoid bone.
• Occasionally, the pneumatization of the
ethmoid bone can extend beyond the
ethmoid bone
• Well pneumatised at birth

15. Group:
• Anterior group
• Posterior group
By basal/ground lamina
from middle turbinate
ETHMOIDAL SINUSES:

16. Anterior group:
• Agger nasi cells – anterior most ethmoid cells
• Ethmoid bulla - posterior boundary of the hiatus
semilunaris.
• Supraorbital sinus – posterior & lateral to frontal sinus
• Frontoethmoid cells – floor of frontal sinus
• Haller cells – pneumatisation of orbital floor
• Concha bullosa – pneumatisation of middle turbinate
Posterior group:
• Onodi cells – most posterior ethmoidal air cells & related
to optic nerve and internal carotid artery.
ETHMOIDAL SINUSES:

17. HALLER’S CELLS CONCHA BULLOSA ONODI CELLS
ETHMOIDAL SINUSES:

18. Roof:
• Related to cranial cavity
• Fovea ethmoid
• Orbital plate of frontal bone
Floor:
• Anteriorly- orbital plate of
maxilla
• Posteriorly- orbital process
of palatine bone
ETHMOIDAL SINUSES:

19. Lateral wall:
• By lamina papyracea, which
separates it from orbit
• Anteriorly – lacrimal bone
• Posteriorly – with lesser wing of
sphenoid
Medially:
• Both middle and superior
turbinate
ETHMOIDAL SINUSES:

20. Arterial supply:
• Anterior and posterior ethmoid artery
• Sphenopalatine artery
Venous drainage:
• Anterior and posterior ethmoidal vein
Lymphatics drainage:
• Submandibular and retropharyngeal lymph nodes
ETHMOIDAL SINUSES:

21. • It occupies the body of sphenoid
• Two sinuses are separated by a
thin bony septum
• Rudimentary at birth
• Bones of Bertin
• Major cause of cavernous sinus
thrombophlebitis
SPHENOID SINUS:
Dimensions:
• 2 cm – height, breadth, depth
• Capacity varies from 0.5 to 30 ml
Average 7.5ml

22. Roof:
• Anteriorly – frontal lobe &
olfactory tract
• Posteriorly - sellae turcica &
optic chiasma
Floor:
• Roof of nasopharynx
• Vidian nerve
SPHENOID SINUS:

23. Lateral wall:
• Cavernous sinus
• Internal carotid artery
• CN 3, 4, 5
SPHENOID SINUS:

24. Anterior wall:
• Supraorbital fissure
• CN 3,4
• Ophthalmic division of CN 5
Posterior wall:
• By thick wall
• Pons
• Basilar artey
SPHENOID SINUS:

25. Arterial supply:
• Sphenopalatine artery br. of maxillary artery
Venous drainage:
• Posterior ethmoidal vein to the superior ophthalmic vein
Lymphatics drainage:
• Retropharyngeal lymph nodes
SPHENOID SINUS:

26. DRAINAGE OF PARANASAL SINUS:
Osteomeatal complex:
It is that area of middle meatus
where sinus ostia of anterior
group of sinuses are surrounded
by uncinate process, ethmoidal
infundibulum and bulla
ethmoidalis.

27. DRAINAGE OF PARANASAL SINUS:
Structures of osteomeatal
complex:
• Uncinate process
• Bulla ethmoidalis
• Ethmoidal infundibulum
• Hiatus semilunaris
• Frontal recess
Even a minor pathology in this area can lead to secondary
sinusitis in major sinuses by obstruction to sinus ostia.

28. DRAINAGE OF PARANASAL SINUS:
Frontal sinus:
• Ethmoidal infundibulum or
frontonasal duct
Anterior ethmoid cells:
• Ethmoidal infundibulum
Bulla ethmoidalis:
• Retrobullar recess
Maxillary sinus:
• Natural ostium
Into the middle meatus:

29. DRAINAGE OF PARANASAL SINUS:
Into the superior meatus:
Into the nasal cavity:
• Sphenoid sinus

30. FUNCTION OF PARANASAL SINUS:
• Air conditioning, i.e. warming and moistening
• Reduction of skull weight
• Heat insulation of orbital & intracranial structures
• Vocal resonance
• Secretion of mucus to keep nasal chambers moist
• Provides mechanical rigidity to skull