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Nasal Cavity and Paranasal
Sinuses
Dr. Wael Mohamed Talaat
Assistant Professor of Oral and Maxillofacial
Surgery
University of Sharjah
Objectives
Knowledge of the anatomy of the
nasal cavity
Knowledge of the anatomy of the
paranasal sinuses and their dental
implications
Nasal Cavity
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 ???
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
Bony framework
Nasal bone
Frontal process of the maxilla
Nasal process of the frontal bone
Bony Framework: Nasal Bone
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 thefrontal process of the maxilla and the medial border meets its fellow in the midline.
Bony Framework:
Frontal process of the maxilla
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.
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.
Bony Framework:
Nasal process of the frontal bone
Cartilaginous framework
• Lateral Superior Nasal cartilage
• Greater Lower Nasal Cartilages
• Minor Alar Cartilages
• Septal Nasal Cartilages
Lateral Superior Nasal cartilage
Lateral Superior Nasal cartilage
Greater Lower Nasal
Cartilage
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.
Minor Alar Cartilages
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.
Septal Nasal Cartilages
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 columellacan also be defined as the tip of the mobile part of the septum.
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
Each half of the nasal cavity has a:
Floor
Roof
Lateral wall
Septal wall
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
The Roof Narrow
Formed by a number of bones and cartilages
Nasal Cartilages, Nasal, Frontal, Ethmoid,Sphenoid Bones
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)
Vomer
Septal
Cartilage
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).
Superior Meatus
Middle Meatus
Inferior Meatus
Paranasal Sinuses
Paranasal Sinuses are air containing
bony spaces around the nasal cavity
Usually lined by respiratory mucous
membrane of ciliated columnar
epithelium
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.
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.
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
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.
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.
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.
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.
Medial wall:
The base or medial wall forms part of the lateral wall of the nose and has the opening (ostium) of the sinus.
√ 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.
√ Divided into several compartments by bony septa (underwood’s septa).
√ Lined with pseduo-stratified columnar ciliary epithelium.
Pneumatization is the enlargement of
the sinus by resorption of the alveolar
bone that formerly served to support a
tooth or teeth
What might be the clinical implications
of maxillary sinus pneumatization ??
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.
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.
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
Mean, standard deviation, minimum and maximum values obtained fromright premolar and molar teeth.
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).
Ethmoid Air Sinus
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.
Sphenoid Air Sinus
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.
Functions of Paranasal Sinuses
Humidifying and warming inspired air
Regulation of intranasal pressure
Increasing surface area for olfaction
Lightening the skull
Resonance
Absorbing shock
Frontal Sinus
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.
Please answer question on slide 4.
Thank You