The document discusses the paranasal sinuses and their clinical considerations. It begins by introducing the four pairs of paranasal sinuses - maxillary, frontal, sphenoidal, and ethmoidal sinuses. For each sinus, it describes the anatomy, development, neurovascular supply, and other key details. It then covers the functional importance of the sinuses and common clinical issues like sinusitis, developmental anomalies, dental issues that could impact the sinuses, and more. The document provides an overview of the paranasal sinuses and factors relevant to their examination and treatment.

1. Paranasal Sinuses & its Clinical
Considerations
Sudeep M. Chaudhari
PG 1st
year
Dept. of Paedodontics & Preventive Dentistry

2. Contents
● Introduction
●
Types of paranasal sinuses
1)Maxillary sinus
2)Frontal sinus
3)Sphenoidal sinus
4)Ethmoidal sinus
●
Functional importance
●
Clinical considerations
● Conclusion
●
References

3. Introduction
● The paranasal sinuses are air-filled spaces located within the
bones of the skull and facial bones. The sinus is regarded by
some as an accessory space to the nasal cavity, occurring only
as a result of an inadequate process of ossification. In contrast,
others report the functional contributions of the maxillary sinus
in many aspects of olfactory and respiratory physiology.
● The sinuses are rudimentary or even absent at birth. They
enlarge rapidly during the ages of six to seven years, i.e. time of
eruption of permanent teeth and then after puberty. From birth
to adult life the growth of the sinuses is due to enlargement of
the bones; in old age it is due to resorption of the surrounding
cancellous bone.

4. Types of paranasal sinuses -
There are 4 pairs of paranasal
sinuses
1) Frontal sinus
2) Maxillary sinus
3) Sphenoidal sinus
4) Ethmoidal sinus

5. 1) Maxillary Sinus
● Definition-
The 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 nasal meatus and the nasal vestibule.
● Anatomy of the maxillary
sinus was first described by
the British surgeon and
anatomist Nathaniel
Highmore in 1651.
● It is also known as the
“Antrum of Highmore”.

6. Develomental aspect
● Maxillary sinus is the first of the paranasal sinus to develop.
●
4th
week intra-uterine life – dorsal portion of 1st
Pharyngeal arch
forms the Maxillary process, which extends forward and
beneath the developing eye to give rise to the maxilla.

7. Horizontal shift of the palatal
shelves & fusion with one another.
Nasal septum separates the oral
cavity from the two nasal
chambers.
Influences further expansion of the
lateral nasal wall & 3 wall begin to
fold.
3 conchae & meatuses arise

8. Superior & Inferior Meatus
Remain as shallow depressions
along the lateral nasal wall for
first half of I.U. life
3 Meatus
Middle Meatus
Expands immediately into lateral
nasal wall in an inferior direction
occupying more of the further
maxillary body

9. ● Development of sinus starts at 12 weeks as an evagination of
the mucous membrane in the lateral wall of the middle meatus
of the nose when the nasalepithelium invades the maxillary
mesenchyme.

10. Age changes of Maxillary Sinus
Tubular at birth
Ovoid in
childhood
Pyramidal in
adulthood

11. 0-3 years
● At birth filled with
deciduous tooth
germs
● Size : 7mm X
4mm X 4mm
● Volume 6-8ml
●
20th
month –
posterior
development
●
3rd
year : 1/2 adult
size
3-4 years
● Increase in width
with facial growth
●
Position : 2nd
deciduous molar
& 1st
permanent
molar
5-9 years
● Size : 27mm X
18mm X 17mm
● Growth
corresponds to
permanent teeth
eruption

12. 9-12 years
● Antral floor same
level with nasal
floor
12-15 years
● Floor of sinus 5-
12mm below
nasal floor
● Size : 32mm X
33mm X 25mm
● Volume : 15-20ml
●
Floor : 1st
molar <
2nd
molar < 2nd
premolar
Old age
● Resorption of
ridge with
continued sinus
pneumatization
which leaves a
thin layer of
corticle bone
separating the
sinus mucosa
from oral mucosa

14. Anatomy of Maxillary Sinus
● Largest of the paranasal sinus
● Pyramidal shaped cavity within
the body of the Maxilla
● The base of the pyramid
forming the lateral nasal wall
and apex at the root of the
zygoma.

15. Roof of the antrum
● Formed by floor of the orbit
and is transversed by the
infraorbital nerves.It is flat
and slopes slightly
anteriorly and laterally.

16. Floor of the sinus
● Curved rather than flat
formed by alveolar process
of the maxilla and lies
about 1cm below the level
of the floor of the nose.
● Closely related to root
apices of the maxillary
premolar and molar.

17. Anterior wall
● Formed by the facial surface of the maxilla.
● Extends from pyriform aperture anteriorly to
zygomaticomaxillary suture & inferior orbital rim superiorly to
alveolar process inferiorly.
● Convexity towards sinus
thinnest in canine fossa
● Important structures -
Infraorbital foramen
Anterior superior alveolar
nerve (ASA)
Middle superior alveolar
nerve (MSA).
Canine Fossa

18. Posterior wall
● Made of zygomatic and greater wing of sphenoid bone.
● A thin plate of bone separate the antral cavity from the
infratemporal fossa.
● Thick laterally, thin medially.
● Important structures -
➢ Posterior superior
alveolar nerve
➢ Maxillary artery
➢ Pterygopalatine
ganglion
➢ Nerve of pterygoid
canal

19. Medial wall
● Bounded by the nasal cavity
● The opening of the sinus is closer to the roof and thus at a higher level than the
floor.
● Formed by lateral nasal wall
● Inferior - nasal conchae
● Posterior - palatine bone
● Superior -uncinate process of
ethmoid,lacrimal bone
● Contains double layer of mucous
membrane(pars membranacea)
● Important structures -
➢ Sinus ostium
➢ Hiatus semilunaris
➢ Ethmoidal bulla
➢ Uncinate process
➢ Infundibulum

20. Ostium
● Opening of the maxillary sinus is called osteum.
● Ostium of the maxillary sinus is situated high up in medial wall and
opens into the middle meatus of the nose in the lower part of the
hiatus semilunaris.
● Lies above the level of nasal floor.
●
The ostium lies approximately 2/3rd
up the medial wall of the sinus,
making drainage of the sinus inherently difficult.
● Blockage of the ostium can easily occur when there is inflammation
of the mucosal lining of the ostium.
● An accessory ostium is also present behind the main ostium in 30%
cases.

21. Neurovascular supply
● Arterial supply :
➔ By facial artery branch of external carotid artery.
➔ By infra orbital & greater palatine arteries branch of
maxillary artery which is branch of external carotid artery.
● Venous:
➔ To anterior facial vein & pterygoid plexus.
➔ Infection from the maxillary sinus may spread to involve
cavernous sinus via any of its draining veins as the
pterygoid plexus communicates with the cavernous sinus
by emissary vein.

22. Neurovascular supply
● Nerve supply :
➔ Anterior superior alveolar nerve
➔ Middle superior alveolar nerve
➔ Posterior superior alveolar nerve
● Lymphatic Drain :
➔ The lymphatic drains in to submandibular lymph nodes.

23. Microscopic Features
● The epithelial layer of maxillary sinus lining is thinner than that of
nasal cavity.
● Lined by Ciliated pseudostratified columnar epithelium derived
from olfactory epithelium of middle nasal meatus
● Most numerous cells -Columnar ciliated cells
● Additional cells- Basal cells,Columnar non-ciliated cells,Goblet
cells

24. Ciliated Cells
● The cilia is composed of typical 9+1 pairs of microtubules &
provide mobile apparatus to the sinus epithelium which moves
the debris, microorganisms and the mucous film lining the
epithelial surface of the sinus into the nasal cavity through the
ostium.

25. Goblet Cells
● It is mucous synthesizing and secreting cells.
● It resembles an inverted wine glass with a short stack like basal
end containing the nucleus and a swollen apical end containing
mucin.
● It is an apocrine gland, i.e it
pours its secretion through
rupture of its apical cell
membrane that get
regenerated. So it has all
the criteria of the
synthesizing and secreting
cells.

26. 2) Frontal Sinus
● Situated in between inner and outer table of frontal bone
● Usually asymmetrical
● Pyramidal in shape with apex upwards and base is formed by the
floor
● Boundaries
➔ Anterior wall-outer table of frontal
bone
➔ Posterior wall- inner table of
frontal bone separates the sinus
from cranial cavity
➔ Floor- formed by thin bone
separating sinus from orbit
➔ Medial wall- forms the septum
between two frontal sinuses

27. ● Average measurements:
➔ Heightt.: 3.2cm
➔ Width: 2.4cm,
➔ Depth: 1.6cm
➔ Capacity- 5-10 ML
● NEUROVASCULAR SUPPLY :
➔ Blood supply - Supra orbital artery
➔ Venous return - Anastomotic veins in supra orbital notch,
connecting supra orbital and superior ophthalmic veins.
➔ Lymphatic drainage – Submandibular nodes.
➔ Nerve supply - Supra orbital nerve(ophthalmic nerve)

28. 3) Sphenoidal Sinus
● There are two sphenoidal sinuses in the sphenoid bone divided
unequally by a thin bony septum
● Relations-
●
Laterally- cavernous sinus containing 3rd
,4th
,5th
,6th
cranial nerves,
internal carotid artery, optic nerve
● Superiorly- pituitary gland,
optic chiasma, olfactory
bulb, frontal lobe
● Inferiorly- nasopharynx
and vidian nerve
● Posteriorly- brainstem,
basilar artery

29. ● NEUROVASCULAR SUPPLY :
➔ Blood supply: Posterior ethmoidal and internal carotid
arteries.
➔ Venous drainage: Pterygoid venous plexuses and cavernous
sinus.
➔ Nerve supply: Posterior ethmoidal nerve and orbital branches
of pterygopalatine ganglion.
➔ Lymphatic drainage: Retropharyngeal nodes

30. 4)Ethmoidal Sinus
● Thin walled air cavities in the lateral masses of ethmoid bone.
● Relations -
➔ Roof- anterior cranial fossa
lateral to cribriform plate
➔ Lateral wall- orbit, optic
nerve, nasolacrimal duct
separated by thin bone
called lamina papyracea
➔ Inferior- maxillary sinus
➔ Posteriorly- sphenoid sinus
➔ Medially- superior and
middle turbinate

31. ● Divided into three groups – anterior, middle, posterior
1) ANTERIOR ETHMOIDAL SINUS :
➔ Has 1 to 11 air cells.
➔ NEUROVASCULAR SUPPLY : Anterior ethmoidal nerve
and vessels.
➔ LYMPHATICS : Submandibular
nodes.
➔ Some of the important anterior
group cells includes
a) Agger nasi cells
b) Ethmoidal bulla
c) Supraorbital cells
d) Frontoethmoidal cells
e) Haller cells

32. 2)MIDDLE ETHMOIDAL SINUS :
➢Has 1 to 7 air cells.
➢NEUROVASCULAR SUPPLY : Anterior ethmoidal nerve and
vessels and orbital branches of pterygopalatine ganglion.
➢LYMPHATICS : Submandibular nodes.
3)POSTERIOR ETHMOIDAL SINUS :
➢Has 1 to 7 air cells.
➢NEUROVASCULAR SUPPLY :
Posterior ethmoidal nerve and
vessels and orbital branches of
pterygopalatine ganglion.
➢LYMPHATICS :
Retropharyngeal nodes.
➢Onodi cells – one of the most
important air cell of this group.

33. Functional Importance
➔ Imparts resonance to the voice
➔ Increases the surface area and lightens the skull
➔ Moistens and warms inspired air
➔ Filters the debris from the inspired air
➔ Mucus production and storage
➔ Limit extent of facial injury from trauma
➔ Provides thermal insulation to important tissues
➔ Serves as accessory olfactory organs.

34. Clinical Considerations

35. Developmental anomalies
• Aplasia – complete absence
• Agenesis – functionally underdevelopment
• Hypoplasia – altered development
➢ Occurs either alone or in association with other anamolies -
➔ Choanal atresia
➔ Cleft palate
➔ High palate
➔ Mandibulofacial dysostosis

36. ● Supernumerary maxillary sinus -
➔ Two competely separated sinuses on the same side
➔ Results in two permanently separated ostia of the sinus
● Pituitary gigantism – all sinuses assume a much larger volume
● Congenital syphilis – small sinuses

37. Maxillary Sinusitis
● Acute Maxillary Sinusitis
➔ Sudden onset
➔ Duration of 4weeks or less
● Subacute Maxillary Sinusitis
➔ Duration of 4 – 12 weeks
● Chronic Maxillary Sinusitis
➔ Duration of atleast 12 weeks

38. Odontogenic origin
● Periapical infection from the
teeth
● Oroantral fistula
● Dental material in antrum
● Traumatic injuries
● Implant
● Infected dental cyst
● Periodontitis
Non-odontogenic origin
● Mechanical obstruction of
ostium
● Bacterial contamination
● Immune deficiency

39. ● Severs pain, constant and
localized
● Area: area of eyeball cheek
frontal region.
● Exacerbated by stooping or
lowering head.
● Referred to : Teeth, orbit,ear
● Pain increased by biting on
affected side but unaffected by
drinking hot cold or sweet fluids.
● Generalized Toxemia: Fever with
chills & nausea
Symptoms
● Nasal discharge : watery in
start, later mucopurulent.
● Nasal mucosa: show
reddening and inflammation
with pus.
● In case of odontogenic
sinusitis: discharge foul odor
● Tenderness to pressure on
swelling over the sinus
Signs

40. Periapical infection from the teeth
● The spread of pulpal disease beyond the confines of the dental
supporting tissues into the maxillary sinus was termed Endo –
antral syndrome (EAS) by Selden (1974).
● The anatomic proximity of the roots of the maxillary bicuspid
and molar teeth to the floor of the sinus leads to potential
infection of the sinus by direct extension of an apical abscess.

41. Oroantral fistula
● Oroantral communication: Abnormal connection between the
oral and antral cavities. When oroantral communication is left
open, epithelial tissue may develop in its track -"oroantral
fistula".

42. Etiology
● Extraction of teeth
● Destruction of portion of floor of sinus by periapical lesion
● Injudicious use of instruments
● Forcing a tooth or a root during the attempted removal
● Extensive trauma to face
● Surgery of maxillary sinus
● Chronic infections
● Implant dentures

43. Symptoms of fresh oroantral
communication:
● Escape of fluids
● Epistaxis
● Escape of air
● Enhanced column of air
● Excruciating pain
Symptoms of established
oroantral fistula:
● Pain.
● Persistent purulent unilateral
nasal discharge.
● Post nasal drip.
● Popping out of antral polyp

44. Dental Material In The Antrum
● During obturation, the sinus may be invaded by either sealer or
by solid materials such as gutta percha or silver cones
● The material produces an inflammatory reaction with an area of
rarefaction in the periapical tissues. Such inflammation is likely
to persist until the foreign object is removed.
Overextended obturating material
into the maxillary sinus

45. Displacement of A Root or Tooth into
Maxillary Sinus
● It is basically a mishap incident results
from a neglected act by the operator
while applying wrong force.
●
Occurs rarely but the 3rd molar and 2nd
premolar are the most at risk of
dislodgement.
● May occur with severe maxillofacial
injuries.
● Removal of root tip can be done through
the tooth socket or through the canine
fossa by Caldwell Luc approach.

46. Conclusion
Due to close proximity of maxillary sinus to orbit, alveolar ridge,
diseases involving these structures may produce confusing
symptoms. Hence a precise information about the surgical
anatomy is essential to dentist.
The close anatomical relationship of the maxillary sinus and the
roots of maxillary molars, premolars and in some instances
canines, can also lead to several endodontic complications.
Clinicians must be particularly cautious when performing dental
procedures involving the maxillary posterior teeth.

47. References
● Chaurasia BD. BD Chaurasia's human anatomy regional and
applied, dissection and clinical volume 3: head, neck and brain.
CBS publishers; 2004.
● Kumar GS. Orban's oral histology & embryology. Elsevier Health
Sciences; 2014 Feb 10.
● Rajendran R. Shafer's textbook of oral pathology. Elsevier India;
2009.
● Ghom AG, Ghom SA, editors. Textbook of oral medicine. JP
Medical Ltd; 2014 Sep 30.
● Neelima AM. Textbook of oral maxillofacial surgery. Jaypee
brothers medical publisher ltd. 2008;1:549-65.