The maxillary sinus is an air-filled space within the body of the maxilla bone. It develops from the lateral nasal wall and communicates with the nasal cavity via the middle meatus. It has a four-sided pyramid shape with four walls. Its epithelial lining contains ciliated pseudostratified columnar cells that help clear mucus and debris. The maxillary sinus serves functions like warming inhaled air, moisturizing dry climates, and protecting the brain from cold temperatures. Clinical considerations include sinusitis, fistulas, and infections of the mucoperiosteal layers.

1. Maxillary sinus
DEPARTMENT OF ORAL PATHOLOGY

2. Introduction
Definition, Structure
Developmental Aspect & Anomalies
Microscopic Features
Functional Importance
Clinical Considerations

3. DEFINATION
“The maxillary sinus is the pneumatic space
that is lodged inside the body of maxilla & communicates
with the environment by way of the middle nasal meatus”
It is also known as the “Antrum of Highmore”
Four-sided pyramid: Base , Apex
Four Sides:1. Anterior2. Posterior3. Superior4. Inferior

4. ANATOMY

6. DEVELOPMENT
Maxillary sinus is the first of the PNS to develop
Initial development of the sinus follows a number of
morphogenic events in the differentiation of nasal cavity in
early gestation.
Horizontal shift of the Palatal Shelves & subsequent fusion
with one another
Nasal Septum separates the 2° Oral cavity from the two nasal
chambers
Influences further expansion of the lateral nasal wall & 3 walls
begin to fold
3 Conchae & Meatuses arise

7. 1. Superior Nasal Meatus
2. Middle Nasal Meatus
3. Inferior Nasal Meatus
Superior & Inferior Meatuses remain as shallow
depressions along the lateral nasal wall for the first half
of IUL, Middle Meatus expands immediately into lateral
nasal wall & expands in an inferior direction occupying
more of the future maxillary body

8. Boundaries:
 Apex – by zygomatic process of Maxilla
 Roof – by orbital surface of Maxilla
(traversed by infra-orbital nerves & vessels)
 Base- by nasal surface of body of maxilla
Arterial Supply:
Supplied by branches of Facial, Maxillary,
Infra-orbital & Greater Palatine Arteries
Periosteal supply is provided by sinus
membrane which is supplied by Posterior-
Superior dental artery or by the Infraorbital
artery (buccaly) and the Palatine artery
(palatally)

9. BLOOD SUPPLY

10. VENOUS DRAINAGE

11. Venous Drainage:
Via the Facial vein, Sphenopalatine vein anteriorly and the
Pterygoid venous plexus posteriorly, Anterior, middle and superior
dental veins drain into the infra-orbital vein .
Pterygoid plexus communicates with the cavernous sinus by
emissary veins
The significance of the vascular drainage of the sinus lies in
the fact that apart from the joining typical pathways in the maxilla
to the jugular veins, it can also drain upward into the ethmoidal and
frontal sinuses and eventually reach the cavernous sinus
in the floor of the brain.
Spread of infections via this route is a serious complication
of maxillary sinus infections.

12. NERVE SUPPLY

13. Lymph Drainage:
Into Submandibular lymph nodes and deep cervical lymph
nodes
and retro pharyngeal nodes
Nerve Supply:
Branches from Anterior, middle and posterior superior
alveolar nerves,
infra orbital nerves; greater palatine nerve

14. MICROSCOPIC FEATURES
Three layers surrounds the space of the Maxillary sinus:
1. Epithelial Layer
2. Basal Lamina
3. Sub-epithelial layer including periosteum
Ciliated Pseudostratified Columnar –> derived from
olfactory epithelium of middle nasal meatus
Most numerous cells -> Columnar ciliated cells
Additional cells :
1. Basal cells
2. Columnar non-ciliated cells
3. Goblet cells (mucus –producing)

15. :
Cilia is composed of 9+1 pairs of microtubules and
provide mobile apparatus to the sinus epithelium.
By ciliary beating, the mucous blanket lining the epithelial
surface moves from the interior of the sinus towards the nasal
cavity
Goblet cells (secretory cells) contains RER & SER along with the
Golgi apparatus all of which are involved in the synthesis of
secretory substances

17. In addition to epithelial secretion, the surface of the
sinus is provided with a mixed secretory product .
This serous secretion consists of water, neutral lipids, proteins,
carbohydrates and a mucous secretion consisting of compound
glycoprotein's and mucopolysaccharides.
These are located in the sub epithelial layer of the sinus and
reach the sinus by excretory ducts .
Ciliated Cells – Ciliary Beating Mucous blanket lining the
epithelium
Moves from sinus to nasal cavity

18. Functions Of Maxillary Sinus
• Functions Of Maxillary Sinus Biological Functions with
nose:
•Warming of inspired air
• Moisturize the air in dry climates (avoids dry throat)
• Accessory Olfactory organ
• Production of bactericidal lysozyme to the nasal cavity
Filters Debris
• Protects brain: By increasing the temperature of inspired
air against exposure to cold air environment

19. Other Functions:
Resonance of voice
 Lightening of skull weight
 Enhancement of craniofacial resistance to mechanical shock
Protects from infection via the production of immunoglobulins
which diminish the frequency of infection from inhaled bacteria,
molds and viruses

20. Clinical consideration
• Fistula
• Chronic infection of mucoperiostial layers
• Maxillay sinusitis

21. FAQ’S
1.Describe in detail of maxillary
sinus.-10 marks
2.Histology of maxillary sinus-5 or
2 marks

22. THANK YOU