Nasal cavity and paranasal sinuses lecture

1. Nasal Cavity and Paranasal
Sinuses
Dr. Wael Mohamed Talaat
Assistant Professor of Oral and Maxillofacial
Surgery
University of Sharjah

2. Objectives
 Knowledge of the anatomy of the
nasal cavity
 Knowledge of the anatomy of the
paranasal sinuses and their dental
implications

3. Nasal Cavity

4. Is the nasal cavity closely related
to our practice ??
 Why did a patient experience bubbling
of blood and escape of fluids through
his nostril following extraction of his
second upper molar ???

5. Functions
 A passageway for air to lungs
 Organ of smell
 Filters impurities from inspired air
 Warms and humidifies inspired air
 Aids in phonation
 Receives secretions from paranasal
sinuses
 Receives secretions from nasolacrimal
duct

6. Bony framework
 Nasal bone
 Frontal process of the maxilla
 Nasal process of the frontal bone

7. Bony Framework: Nasal Bone

8. Bony Framework: Nasal Bone
 The two nasal bones form the upper part
of the bridge of the nose. Each nasal
bone is quadrilateral, being longer than it
is wide.
 The superior border articulates with the
nasal part of the frontal bone.
 The inferior border forms the superior
boundary of the anterior nasal aperture.
 The lateral border meets the
frontal process of the maxilla
and the medial border meets
its fellow in the midline.

9. Bony Framework:
Frontal process of the maxilla

10. Bony Framework:
Frontal process of the maxilla
 The frontal process of the maxilla
projects postero-superiorly from the
body of the maxilla and is situated
between the nasal bone in front and
the lacrimal bone behind. The process
articulates apically with the frontal's
nasal part, the anterior border with the
nasal bone and the posterior border
with the lacrimal bone.

11. Bony Framework:
Nasal process of the frontal bone

12. Bony Framework:
Nasal process of the frontal bone
 The nasal part of the frontal bone is a
small, thin plate of bone that projects
antero-inferiorly in the midline
between the supra-orbital margins and
forms a small portion of the roof of the
nose.

13. Cartilaginous framework
• Lateral Superior Nasal cartilage
• Greater Lower Nasal Cartilages
• Minor Alar Cartilages
• Septal Nasal Cartilages

14. Lateral Superior Nasal cartilage

15. Lateral Superior Nasal cartilage

16. Greater Lower Nasal
Cartilage

17. Lateral Superior & Greater Nasal cartilages
 The lateral (upper) nasal cartilages
and the greater (lower) nasal
cartilages support the lateral surfaces
of the external nose. The lateral nasal
cartilages are triangular plates. They
are united in the midline with each
other and with the septal cartilage.

18. Minor Alar Cartilages

19. Minor Alar Cartilages
 The minor alar cartilages are found at
the back of the major nasal cartilages,
embedded in fibrous tissue that
connects them to the maxilla.
 Function
Extend to maintain the patency of the
anterior nares.

20. Septal Nasal Cartilages

21. Septal Nasal Cartilages
 The cartilaginous elements form the
lower part of the external nose and in the
midline lies the septal cartilage. It is
quadrangular and fits posteriorly into the
notch between the perpendicular plate of
the ethmoid bone and the vomer. The
septal cartilage is also attached to the
nasal crest of the maxilla and to the
anterior nasal spine. The septal cartilage
at the apex of the external nose is
termed the 'columella'. The columella
can also be defined as the tip of the
mobile part of the septum.

22.  The entire nasal
cavity extends from
the nares (nostrils)
anteriorly to the
choanae posteriorly Choanae
•It is divided into 2
parts by an
osseocartilaginous
nasal septum

23. Each half of the nasal cavity has a:
 Floor
 Roof
 Lateral wall
 Septal wall

24. The Floor
 Palatine process
maxilla
 Horizontal plate
palatine bone
(the superior surface of
the hard palate)
http://www.netterimages.com/images/vtn/000/000/001/1966-150x150.jpg

25. The Roof
 Narrow
 Formed by a number of bones and cartilages
Nasal Cartilages, Nasal, Frontal, Ethmoid,Sphenoid Bones

26. The Nasal Septum (the medial wall)
Divides the nasal cavity into right and left halves
It is part osseous and part cartilaginous
Perpendicular
Plate (ethmoid)
Septal
Cartilage Vomer

27. The Lateral Walls
Marked by 3
projections:
◦ Superior concha
◦ Middle concha
◦ Inferior concha
The area below each
concha is referred to as a
meatus (passageway).

28. Superior Meatus

29. Middle Meatus

30. Inferior Meatus

31. Paranasal Sinuses

32.  Paranasal Sinuses are air containing
bony spaces around the nasal cavity
 Usually lined by respiratory mucous
membrane of ciliated columnar
epithelium

33.  Four pairs of paranasal sinuses surround
the nasal cavities and are named from the
bones
in which they are located: maxillary,
frontal, sphenoid, and ethmoid sinuses.

34.  The maxillary sinuses are located lateral to
the nasal cavities. Each of the two sinuses is
pyramidal in shape with the apex of each
located near the zygomatic bone.

35.  The maxillary sinus is the first of the
paranasal sinuses to develop, and its
growth ends with the eruption of the
third molars at approximately 20 years
of age

36. Roof:
 The roof of the
sinus is part of the
floor of the orbit
and contains the
infra-orbital canal,
which transmits
the infra-orbital
nerve and
vessels.

37. Floor
 The alveolar
process and part
of the palatine
process of the
maxilla form the
floor of the sinus,
which lies below
the level of the
floor of the nose
and is related to
the roots of the
teeth.

38. Apex:
 The apex extends into the
zygomatic process of the
maxilla.
Anterior wall
 The anterior wall of the
maxillary sinus is the facial
surface of the maxilla.

39. Posterior wall
 The posterior wall
is the
infratemporal
surface of the
maxilla. The
posterior superior
alveolar nerve
and vessels pass
through canals in
the posterior
surface of the
sinus.

40. Medial wall:
 The base or
medial wall
forms part of
the lateral
wall of the
nose and has
the opening
(ostium) of
the sinus.

42. √ Size varies from one person to
another.
√ Asymmetry existed in the same
individual.
√ Small in children and grows up with
aging.
√ Average height is about 3.5 cm,
depth 3.2 cm and width 2.5 cm.
√ Capacity of about 15 cc.

43. √ Divided into several compartments by
bony septa (underwood’s septa).
√ Lined with pseduo-stratified columnar
ciliary epithelium.

44.  Pneumatization is the enlargement of
the sinus by resorption of the alveolar
bone that formerly served to support a
tooth or teeth

46.  What might be the clinical implications
of maxillary sinus pneumatization ??

48.  Each maxillary sinus communicates
with the nasal cavity by the ostium
which opens into the middle nasal
meatus under the overlapping middle
nasal turbinate. Although the ostium is
located at a higher level than the floor
of the maxillary sinus, the normal
sinus drains satisfactorily because of
the action of the cilia of the
pseudostratified columnar epithelium.

50.  Kilic C et al, An Assessment of the
Relationship between the Maxillary
Sinus Floor and the Maxillary
Posterior Teeth Root Tips Using
Dental Cone-beam Computerized
Tomography, Eur J Dent. 2010
October; 4(4): 462–467.

51. Mean, standard deviation, minimum and maximum values obtained from
right premolar and molar teeth.
N Mean Std. Dev. Minimum Maximum
R 1st pm 87 8.42 9.10 −1.32 28.52
R 2nd pm 87 3.75 6.67 −21.00 23.70
R 1st mo bm 87 1.77 6.10 −5.41 27.55
R 1st mo bd 87 0.70 4.69 −4.71 27.17
R 1 st mo pal 87 1.86 6.06 −4.22 29.46
R 2nd mo bm 87 0.42 2.85 −5.06 16.45
R 2nd mo bd 87 0.25 2.17 −5.97 8.76
R 2nd mo pal 87 1.06 2.36 −4.52 9.57
R 3rd mo bm 87 1.63 3.33 −2.67 8.41
R 3rd mo bd 87 0.62 3.40 −3.50 8.48
R 3rd mo pal 87 0.92 3.32 −2.87 8.54

52.  Their results showed that the distance
between sinus floor and root tip was
longest for the first premolar root tip
and shortest for the second molar
buccodistal root tip for both right and
left sides. No statistically significant
differences were found between the
right and left side measurements or
between female and male patients
(P>.05).

53. Ethmoid Air Sinus

54. Ethmoid Air Sinus
 The ethmoid sinus is each of the two
paranasal sinuses within the ethmoid
bone, comprising the ethmoidal air
cells and filled with air. They lie
between the upper parts of the nasal
cavities and the orbits, and are
separated from these cavities by thin
bony laminae.

55. Sphenoid Air Sinus

56. Sphenoid Air Sinus
 The two sphenoidal sinuses are
contained within the body of the
sphenoid and they vary in size and
shape; owing to the lateral
displacement of the intervening
septum.

57. Functions of Paranasal Sinuses
 Humidifying and warming inspired air
 Regulation of intranasal pressure
 Increasing surface area for olfaction
 Lightening the skull
 Resonance
 Absorbing shock

58. Frontal Sinus

59. Frontal Sinus
Within the frontal bone are two funnel-shaped cavities, termed the '
frontal air sinuses '.
They lie above and behind the superciliary arches immediately above
the roof of the nasal cavity and may extend into the medial part of the
roof of the orbit. In such cases, a thin layer of bone separates the sinus
from the floor of the cranial cavity and from the roof of the orbit.

60.  Please answer question on slide 4.

61. Thank You