The document provides an extensive overview of the paranasal sinuses, specifically detailing the maxillary sinuses, their anatomy, structure, and functions. It discusses the processes of pneumatization, microscopic features, and the sinus's clinical significance, including common conditions such as maxillary sinusitis, its causes, and complications related to dental procedures. Additionally, it highlights the anatomical relationships and implications of infections, emphasizing the importance of understanding sinus anatomy in dentistry and maxillofacial surgery.

7. Paranasal sinuses

8. Paranasal sinuses

9. Paranasal sinuses
 Paranasal Sinuses (PNS) are air
containing bony spaces around the nasal
cavity. Usually lined by respiratory mucous
membrane of ciliated columnar epithelium
4 paired (bilateral) PNS are: Maxillary
Frontal, Sphenoidal ,Ethmoidal

10. Sinus
 LATIN word meaning a Fold or Pocket.

11. TYPES
named according to the bone in which they
lie.
1) The Maxillary sinuses: largest of the
paranasal sinuses ,are under the eyes in
the maxillary bones.

12. Maxillary Sinuses
Copyright © 2005, Mosby, Inc.

13. Types of paranasal sinuses
 2) The frontal sinuses: superior to eyes in
the frontal bone which forms the hard part
of the forehead.

14. FRONTAL SINUSES

15. Types of paranasal sinuses
 3) the ethmoid sinuses: which are formed
from several discrete air cells within the
ethmoid bone between the nose and eyes.

16. Ethmoid sinuses

17. Sphenoid sinus
 4) The sphenoid sinuses in the sphenoid
bone at the centre of skull base under the
pituitary gland.

18. Lateral Sinus Anatomy

19. Maxillary sinus
 Maxillary sinus is the pneumatic space
that is lodged inside the body of the
maxilla and that communicates with the
environment by way of the middle meatus
and the nasal vestibule

20. ANTRUM
 Maxillary sinus is also called “ maxillary
antrum” .ANTRUM IS A GREEK WORD
MEANING “CAVE”.
 ATTRIBUTED TO NATHIENEL
HIGHMOORE ENGLISH PHYSICIAN
1600.

21. Dr NATHANIEL HIGHMOORE

22. Maxillary sinuses

23. PARANASAL SINUSES

24. STRUCTURE OF MAXILLARY SINUS
 ANATOMY: FOUR SIDED PYRAMID
 BASE: medially towards nasal cavity
forming the lateral nasal wall.
 APEX: Extends laterally into the body of
zygomatic bone.
 ROOF( upper wall): Floor of the orbit.
 FLOOR: Alveolar process

25. PYRAMID

26. Boundaries

27. Walls of maxillary sinus

28. Occipitomental view

29. Size
 Adult maxillary sinus averages 34 mm in
anteroposterior direction
 Height= 33 mm
 Width= 23 mm.
 Volume of max sinus=15 to 20 ml.

30. Radiological view

31. Maxillary sinus
Osteum: at the base of sinus.
Level: Middle nasal meatus
Accessory ostia: 2 or more
connect the sinus with middle
nasal meatus.

32. Osteum of max sinus

34. Pneumatization
 Physiologic process that occurs in all paranasal sinus during the
growth period causing them to increase in volume.
 Pneumatization is the enlargement of the sinus by
resorption of alveolar bone that formerly served to
support a missing tooth or teeth and then occupies the
edentulous space. A thin cortex remains over the
alveolar ridge (arrow) to maintain a normal contour
 Gradual pneumatization continuous process persisting
throughout life.

35. PNEUMATIZATION
 EXPANSION OF MAXILLARY SINUS
GREATER BASALLY IMPINGING MORE
AND MORE ON ALVEOLAR PROCESS.

36. pneumatization???
 Pneumatization of alveolar process is
believed to result from disuse atrophy
initiated by tooth removal.

37. Periapical xray normal sinus

38. Pneumatization

39. Pneumatization of the sinus. Extension of the maxillary
sinus into the tuberosity as a result of pneumatization

40. RECESSES
 RECESSES: The maxillary sinus pneumatization may
extend into nearby bony elements as recesses - infero-
medially into hard palate, laterally into zygomatic bone
and posteriorly into ethmoids So, the expansions of
maxillary sinus beyond the maxillary bone are known as
recesses. Found in alveolar process(50 %), zygomatic
process(41.5%),frontal process(40.5%),Palatine process
(1.75%).
 Some processes of maxilla get invaded by air spaces
and these are called recesses

41. Alveolar recess

42. Recesses

43.  ZYGOMATIC RECESS= Superior alveolar nerves plus
vessels in proximity with sinus.
 Frontal Recess= invades and surrounds the contents of
infraorbital canal.
 Alveolopalatine recess; reduce the amount of bone
between dental apices and sinus space.most often
pneumatizes the floor of sinus adjacent to the roots of
the first molar.
 Fully developed alveolar recess= 3 depressions
separated by 2 incomplete bony septa.
 Anterior depression=premolar buds site
 Middle depression=molar buds, posterior depression=
third molar bud

45. Microscopic features
 3 layers surround the space of the max sinus :
 1) Epithelial Layer
 2) Basal lamina
 3) Subepithelial layer including the periosteum.
 Most numerous cells in max sinus are –
Columnar ciliated cells.
 Additional cells:Basal cells, columnar non
ciliated cells, mucus secreting goblet cells

46. Histology of max sinus

47. Epithelium
 Ciliated Pseudostratified, columnar
derived from olfactory epithelium of
middle meatus
 Most numerous cells in max sinus
epithelium Columnar ciliated cells.
 Additional cells:1)Basal cells 2)columnar
non ciliated cells 3)mucus secreting goblet
cells

48. MICROSCPIC FEATURES

49. MICROSCPIC FEATURES

50. MICROSCPIC FEATURES

51. MICROSCOPIC FEATURES

52. Ciliated cells
 Cilia is composed of typical 9+1 pairs of
microtubules and provide mobile
apparatus to the sinus epithelium

53. Ciliated cells

54. Scanning Electron microscopy of nasal/sinus cilia (orange in this
image). The pink ball is a speck of pollen. The gray blobs are dust
particles

55. Pathway of sinus drainage inside the maxillary sinus.
Ciliated cells continually sweep mucous towards the
ostium.

56. Ciliated cells
 The ciliated cells enclose the nucleus &
electron lucent cytoplasm with numerous
mitochondria & enzyme containing
organelles.

57. Ciliated cells
 The basal bodies serve as attachment of
ciliary microtubules.
 The cilia provide motile apparatus.

58. Ciliated cells
 By ciliary beating, the mucous blanket
lining the epithelial surface moves from
the interior of the sinus towards the nasal
cavity

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

60. Goblet GLASS

61. GOBLET CELLS

62. Subepithelial layer
 Contain subepithelial glands and reach the sinus
lumen by way of excetory ducts.
 The glands contain both serous and mucous
acini i.e secrete serous as well as mucous
secretion.
 Myoepithelial cells surround the acini composed
of either both secretory cells
or a pure population of cells of either secretory
type.

63. Subepithelial layer
 The subepithelial layer also consists of
collagen bundles,fibroblasts,vessels and
nerves.

64. Composition
 serous secretion= water, neutral lipids,
proteins, carbohydrates.
 mucous secretion=compound
glycoprotein's and mucopolysaccharides

65. Subepithelial glands
 AUTONOMIC NERVOUS SYSTEM(ANS)
Control secretions from these glands.
Supplied to max sinus from max nerve
complex.

67. Functions Of Maxillary Sinus
 Warming/Humidification of air.
 Contribution to immune response i.e bactericidal
lysozyme .
 Lightening the skull
 Resonance to voice
 Assistance in regulation of intracranial pressure
 Enhance Facio-cranial resistance to shock

68. Nerve Supply
 Nerve Supply:
MAXILLARY DIVISION OF V
NERVE i.e V2
 1) Anterior, middle
and posterior superior
alveolar nerves,
 2) Infra orbital nerves
 3) greater palatine
nerve

69. Maxillary nerve

70. GREATER PALATINE NERVE

71. INNERVATION
 The innervation of the sinus is important from a
diagnostic standpoint. Post wall of the sinus
receives its supply from Posterior and Middle
Superior Alveolar nerves while anterior wall is by
Anterior Superior Alveolar Nerve. These nerves
travel enclosed in the wall of the sinus
innervating the related teeth (Wallace 1996).
Thus it is commonly seen that pain of the sinus
is mimicked as toothache and vice versa and is
difficult to distinguish

72. Arterial supply
 Major blood supply from branches of maxillary
artery
1) infraorbital artery
2) posterior superior dental artery
3) anterior superior dental artery
4) greater palatine
5) sphenopalatine
Smaller contribution from facial artery
both branches of external carotid artery.

73. EXTERNAL CAROTID

74. FACIAL ARTERY

75. SPHENOPALATINE ARTERY

76. Venous Drainage
 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

77. Venous Drainage

78. VENOUS DRAINAGE

79. CLINICAL IMPORTANCE
 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

80. Lymph Drainage
 PREAURICULAR NODES
 Submandibular lymph node
 PAROTID node
 Facial node

82. CLINICAL CONSIDERATIONS

83. CLINICAL CONSIDERATIONS
 Developmental anomalies
 Agenesis( complete absence of max sinus)
 Aplasia( altered development)
 Hypoplasia(underdevelopment)
 Supernumerary sinus(occurrence of 2
completely separated sinuses on the same side)

84. CLINICAL CONSIDERATIONS
 Pituitary gigantism: sinuses larger than normal
 Some congenital infections: sinuses smaller
than normal
e.g congenital syphilis
 Pathologically generated- functional and
systemic association
 Transfer of pathologic condition is through
Mechanical blood or lymphatic system.

85. Hypoplasia
Maxillary sinus hypoplasia presence of three of following four criteria:
 1. oval-shaped sinus
2. absence of pneumatization of the sinus
below the level of the nasal floor
 3. presence of medial wall of the sinus laterally
to a vertical line drawn tangentially to the
medial orbital border
 4. lateral extension of the sinus medial to a
vertical line drawn through the middle of the
orbit at the level of the infundibulum, in the
coronal plane

86. HYPOPLASIA

87. HYPOPLASIA OF MAXILLARY SINUS

88. MAXILLARY SINUS HYPOPLASIA

89. HYPOPLASIA OF MAXILLARY
SINUS

90. Clinical considerations
 Chronic infections of mucoperiosteal layer cause
neuralgia becoz of superior al n invovolvement.
 Neuralgia of maxillary nerve “tic doulorex”
may mimic sinus pain
 Non specific bacterial sinusistis
 Infections caused by
streptococci,staphylococci,pnemococci,virus of
common cold.

91. Clinical considerations/importance/implications
 1) Oroantral communication
accidental opening in the floor of the
antrum caused during extraction of
maxillary first molar which has a thin bone
separating the roots from the antrum.
a tract b/w oral cavity and max antrum not
lined by epithelium.

92. Fates of oro antral communication
 Either close spontaneouly
 Become epithelialized and persist as true
fistulae

93. OROANTRAL COMMUNICATION

94. Oroantral commmunication/fistula
CAUSES
 Surgical extraction of first molar
 Extraction of tooth showing
hypercementosis
 Radicular cyst
 Granuloma
 Abscess
Therefore surgical intervention necessary

95. EXTRACTION OF FIRST MOLAR

97. PERIAPICAL LESION OR
GRANULOMA CAUSING OAF

98. Pituitary gigantism

99. Tic doulourox( trigeminal neuralgia)

100. Malignant lesions
 Malignant lesions
adenocarcinoma
squamous cell carcinoma
osteosarcoma
fibrosarcoma
lymphosarcoma

101. Malignant lesions
 Primary manifestation in max teeth
1) pain
2) loosening
3) Supraeruption
4) bleeding in gingival tissue

102. MALIGNANT LESION

103. AXIAL VIEW CT SCAN

104. CORONAL VIEW CT SCAN

105. CT SCAN REPORT

106. CLINICAL
CONSIDERATIONS/IMPLICATIONS
 Infections introduced into the antrum
through periapical infections.

107. Infections introduced into the antrum
through periapical infections.

108. Maxillary sinusitis

109. Maxillary sinusitis

110. Signs symptoms
 When you begin to experience maxillary sinusitis you will
notice the following symptoms:
 • Nasal congestion
• Facial pain
• Differentiated facial sensations
• Night-time coughing
• Jawbone pain
• Teeth pain
• Runny nose
• Sinus pressure
• Chronic tooth aches

111. Axial CT showing a displaced tooth root into
the right maxillary sinus causing sinusitis

112. Maxillary Sinusitis of Dental
Origin :
 Maxillary Sinusitis of Dental Origin Spread of infection
from Periapical or Pdl. Abscess Due to overextension of
Sealers, Cements, GP, Silver cones As a result Of
Periapical Surgery of posterior maxillary teeth Due to
iatrogenic Causes like Perforation of Sinus membrane
Or breakage of Instrument
 Maxillary Sinusitis of Dental Origin Spread of infection to
the sinus from a dental abscess: Commonest cause of
direct spread of oral infection to the sinus is a “Periapical
abscess” Odontogenic sinusitis is seldom associated
with acute abscess. It is always secondary to chronic
suppuration from a granuloma or a periodontal abscess

113. Maxillary Sinusitis of Dental
Origin :
 Some common causes of maxillary sinusitis related to dentistry are the
iatrogenic displacement of a maxillary tooth root tip into the sinus during
extraction, perforation of the sinus membrane during exodontia,
andextrusion of materials used in root canal therapy into the sinus. When
teethadjacent to a lone-standing molar have been removed, alveolar bone
isresorbed over time mesial and distal to the remaining tooth. This
resorptionresults in thinner alveolar bone separating the oral cavity and
sinus. If ata later time the lone-standing molar requires extraction, the risk of
alveolarbone or maxillary tuberosity fracture with concomitant oroantral
commu-nication is high. Other oral and maxillofacial surgery or dental
procedures,such as maxillary orthognathic surgery, preprosthetic surgery,
sinusmembrane lifts and sinus grafting, and dental implant placement,
haveoccasionally been cited as causing sinusitis. The incidence of sinusitis
withthese procedures, when properly performed is almost nonexistent,
howev

114. Displacement of root into maxillary sinus during
extraction of a tooth.