2.  Introduction
 Definition, Structure & Variations
 Developmental Aspect & Anomalies
 Microscopic Features*
 Functional Importance
 Clinical Considerations
 Revision & Conclusion!

4.  “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”

5.  Four-sided pyramid
 Base
 Apex

7. Four-Sided
Pyramid

8.  Four Sides:
1. Anterior
2. Posterior
3. Superior
4. Inferior

11.  Perforation at the level of middle nasal
meatus
 Accessory Ostia-In 23% Population
 Different locations of ostium

12.  Some processes of maxilla get
invaded by air spaces & these
expansions k/a recesses
 Later pneumatizes floor of
sinus adjacent to roots of
Molars

13.  Fully developed alveolar recess:
Three depressions separated by two
incomplete bony septa
1. Anterior
2. Middle
3. Posterior

15.  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 (32 mm CRL)

16.  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

19. 1. Superior Nasal Meatus
2. Middle Nasal Meatus
3. Inferior Nasal Meatus

20. 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

21.  Development
of sinus starts
at 12 weeks as
an evagination
of the mucous
membrane in
the lateral wall
of the middle
meatus

22. In its development:
 Tubular at birth
 Ovoid at childhood
 Pyramidal in
adulthood

24. Three Growth Spurts
1. Birth-2.5 years
2. 7.5-10 years
3. 12-14 years

25.  Agenesis(complete absence), Aplasia &
Hypoplasia(altered development or under
development) of the sinus occurs either alone
or in association with other anomalies like:
 Chonal atresia
 Cleft palate
 Septal deformity
 Absence of concha
 Malformation of external nose

30.  Three layers surround the space of the
Maxillary sinus:
1. Epithelial Layer
2. Basal Lamina
3. Sub-epithelial layer including periosteum

31.  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

33.  The cilia is composed of typical
9+1 pairs of microtubules &
provide mobile apparatus to the
sinus epithelium

34.  The ciliated cells enclose the
nucleus & electron-lucent
cytoplasm with numerous
mitochondria & enzyme
containing organelles

35.  The basal bodies serve as
attachment of ciliary
microtubules
 The cilia provide motile
apparatus

37.  By ciliary beating the mucous
blanket lining the epithelial
surface moves from the interior
of the sinus towards the nasal
cavity

38.  Basal segment contains nucleus
 Goblet cells contain RER & SER along with
Golgi apparatus, all of which are involved in
synthesis of secretory substances
 This means that they contain all the
characteristics of secretory cells

40.  They are located in the subepithelial
layers of the sinus & reach the sinus
lumen by the way of excretory ducts
 The glands contain both serous &
mucous acini
Myoepithelial Cells
 Surrounded by acini

42.  The subepithelial layer consists
of collagen bundles, fibroblasts,
vessels & nerves

44.  In addition to epithelial
secretion, the surface of the
sinus is provided with a mixed
secretory product

45.  The serous secretion consists
of water, neutral
lipids, proteins, carbohydrates
& a mucous secretion
consisting of compound
glycoproteins &
mucopolysaccharides

47.  These are located in the
subepithelial layers of the sinus
& reach the sinus lumen by way
of excretory ducts

48.  Mucous blanket lining the sinus
epithelium moves from the
sinus to nasal cavity

50.  Three types of
mucociliary flow have
been described:
1. Smooth-Moving at
0.85cm/min
2. Jerky-Moving at
0.30cm/min
3. Mucostasis-Moving at
less than 0.30cm/min

53.  Warming/Humidification of air
 Contribution to immune response
 Lightening of skull
 Resonance to voice
 Assistance in regulation of intracranial
pressure
 Enhance facio-cranial resistance to shock
 Most recent research on sinus
function has focused on Molecular
NO

54. 1. Superior dental nerve
2. Infraorbital nerve
3. Greater palatine nerve

55.  Internal maxillary artery via:
1. Infraorbital artery
2. Posterior superior dental
artery
3. Anterior superior dental
artery

56. 1. Inferior ophthalmic vein
2. Anterior facial vein

57.  Submandibular lymph nodes

59.  Developmental Anomalies:
 Agenesia
 Aplasia
 Hypoplasia
 Supernumerary sinus

60.  Pituitary gigantism-Sinuses larger than normal
 Some congenital infections-Sinuses smaller
than normal
Example: Congenital Syphilis by Spirochetes
 Pathologically generated-Functional & systemic
association
Transfer of pathologic condition is through
MECHANICAL, BLOOD or LYMPHATIC SYSTEM

61.  Oroantral Fistula [Maxillary Molars]
˜ Surgical Manipulation for extraction
˜ Extraction of tooth showing Hypercementosis
˜ Radicular cyst
˜ Granuloma
˜ Abscess
˜ Therefore, RADIOGRAPHIC INTERVENTION is
necessary

62.  Chronic infections of the
mucoperiosteal layer cause Neuralgia
 Neuralgia of Maxillary nerve-’tic
douloreux’
 Non-specific bacterial sinusitis

63.  Infections caused by streptococci,
staphylococci, pneumococci, virus of
common cold
 Malignant Lesions:
˜ Adenocarcinoma
˜ Squamous cell carcinoma
˜ Osteosarcoma
˜ Fibrosarcoma
˜ Lymphosarcoma