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
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.
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.
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.
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
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.
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
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
44.
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
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.
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.
65. Subepithelial glands
AUTONOMIC NERVOUS SYSTEM(ANS)
Control secretions from these glands.
Supplied to max sinus from max nerve
complex.
66.
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
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.
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
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
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
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
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
The maxillary sinuses appear rectangular in the lateral image but they are really pyramidal in shape and have 3 walls.
The apices project inferiorly and laterally
There are several conic elevations at the floor of the maxillary sinuses for roots of the first and second molar teeth. Occasionally these roots can allow infections originating int eh teeth to travel to the sinuses.
Maxillary sinus membrane. Light micrograph of a section through a mucous membrane from one of the two paired maxillary sinuses. The sinuses are the spaces in the facial bones of the skull, and the maxillary sinuses are found in the upper jaw bones (maxillae). The mucous membrane (mucosa) comprises columnar epithelial (surface) cells (across top) that include many goblet cells that secrete mucus. This outer layer is supported by a richly vascular (containing many blood vessels) layer called the lamina propria (across bottom). The mucosa serves to trap particles in inspired air, and also helps to humidify and heat inspired air
Odontogenic periapical pathology originating from the premolar tooth has invaded the floor of the maxillarysinus (arrow). There is associated reactive sinus mucosal thickening