Transcript nasal cavity and paranasal sinuses

NASAL CAVITY AND
PARANASAL
SINUSES
Dr. Vohra
THE NOSE
THE NOSE
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The external nose
has a free tip
(apex) and a root
(bridge).
The external
orifices are the two
nostrils (nares).
Each nostril is
bounded medially
by the nasal
septum.
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THE NOSE
The nostrils
are bounded
laterally by
the alla.
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NOSE
The framework of the
nose is made:
• Above by :
– The nasal bones;
– The frontal
processes of the
maxillae;
– The nasal part of
the frontal bone
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Below by hyaline
carilages:
– Upper nasal
cartilages
– Lower nasal
cartilages
– Septal catilage
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Blood Supply of the External Nose
The skin of the external nose is supplied by
branches of the ophthalmic and the maxillary
arteries.
The skin of the ala and the lower part of the septum
are supplied by branches from the facial artery.
Nerve Supply of the External Nose
The infratrochlear and external nasal branches of
the ophthalmic nerve (CN V) and the infraorbital
branch of the maxillary nerve
NASAL CAVITY
BOUNDARIES
NERVE SUPPLY
BLOOD SUPPLY
LYMPH DRAINAGE
BOUNDARIES
• From the nostrils
in front
• to the choanae
behind
• Divided into right
and left half by the
nasal septum
• Each half has:
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Floor
Roof
Lateral wall
Medial wall
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Boundaries of the Nasal Cavity
•
The floor (this is the upper surface of the hard palate) is made from:
– The palatine process of the maxilla and
– The horizontal process of the palatine bone
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The roof is narrow and it is formed, from behind forward, by:
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The body of the sphenoid
The cribriform plate of the ethmoid
The frontal bone
The nasal bone
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The nasal cartilages
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The lateral wall of the nose
• The lateral wall
has three
projections
called the:
– Superior
concha
– Middle
concha
– Inferior
concha
• The area below
each concha is
called a meatus.
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The lateral wall of the nose
• The area below
each concha is
called a meatus.
– Superior
meatus
– Middle
meatus
– Inferior
meatus
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Openings in the Superior Meatus
• The superior meatus
lies below and lateral to
the superior concha.
• The sphenoethmoidal
recess lies anterior to
the body of the sphenoid
bone.
– It receives the opening
of the sphenoidal air
sinus.
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– It receives the openings
of the posterior
ethmoidal air sinuses
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Openings in the Middle Meatus
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The middle meatus lies below and lateral to the middle concha.
– It has on its lateral wall a rounded prominence, the bulla ethoidalis.
– Bulla ethmoidalis is caused by the bulging of the underlying middle ethmoidal
air sinuses, which open on its upper border.
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Hiatus semilunaris is a curved cleft below the bulla.
– It leads into a funnel-shaped channel called the infundibulum
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– The frontal sinus opens into and
continuous with the infundibulum.
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Openings in the Middle Meatus
• The maxillary sinus opens in the middle meatus via
hiatus semilunaris.
• The anterior ethmoidal sinuses also open in the
infundibulum.
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Structures related to the middle meatus
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The middle meatus is coninuous anteriorly with a depression called the
antrum.
The antrum is limited above by a ridge called agger nasi.
Below and in front of the antrum is the vestibule.
It is lined by modified skin and has short hairs called vibrissae.
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Openings in the Inferior Meatus
• The inferior meatus lies below and lateral to the inferior concha.
• It receives the opening of the nasolacrimal duct.
• The opening of the nasolacrimal duct is garded by a fold of mucosa,
forming an imperfect valve.
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Medial wall of the nose
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The medial wall (the nasal septum) is an osteocartilaginous
partition, covered by mucous membrane.
It is formed by:
– the vertical (perpendicular) plate of the ethmoid bone,
– the vomer and
– the septal cartilage.
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MUCOUS MEMBRANE
• It lines all the nasal cavity, with the
exception of the vestibules (lined with
modified skin).
• Two types of mucous membrane:
– olfactory
– respiratory
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OLFACTORY MUCOSA
• On the lateral wall, it lines the upper surface of
the superior concha and the spheno-ethmoidal
recess.
• On the medial wall, it lines the superior part of
the nasal septum.
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RESPIRATORY MUCOSA
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It lines the lower part of the nasal cavity.
It functions to moisten, clean and warm the inspired air.
The air is moistened by the secretion of numerous serous glands.
The air is warmed by a submucous venous plexus.
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NERVE SUPPLY TO THE NASAL CAVITY
• The olfactory nerves arise from the central axons of the
olfactory nerve cells.
• They ascend through the cribriform plate to reach the
olfactory bulbs.
• The nerves of ordinary sensation are branches of the
ophthalmic division (CnV1) and the maxillary division
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(CnV2) of the trigeminal nerve
ARTERIAL BLOOD SUPPLY
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It comes mainly from branches of the maxillary artery.
The most important branch is the sphenopalatine artery.
This artery anastomoses with the septal branch of the superior labial
artery in the region of the vestibule.
This is a common site of bleeding from the nose (epistaxis).
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LYMPH DRAINAGE
• The vestibule of
the nasal cavity is
drained into the
submandibular
lymph nodes.
• The reminder of
the nasal cavity is
drained into the
upper deep
cervical lymph
nodes.
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PARANASAL
SINUSES
MAXILLARY
FRONTAL
SPHENOIDAL
ETHMOIDAL
DEFINITION
• They are cavities
inside the:
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Maxilla
Frontal bone
Sphenoid bone
Ethmoid bone
• They are:
– Lined with
mucoperiosteum;
– Filled with air;
– Communicate with
the nasal cavity.
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Functions of the Paranasal Sinuses
• Reduce the weight of the skull.
• Resonators of the voice.
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Drainage of Mucus and
Function of Paranasal Sinuses
• The mucus produced by the mucosus membrane is
drained into the nose by the ciliary action of the
columnar cells.
• It is also helped by siphon action created during
blowing of the nose.
• When the apertures of the sinuses are blocked or when
they are filled with fluid, the quality of the voice
becomes markedly changed.
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MAXILLARY SINUS
• It is located within the
body of the maxilla
behind the skin of the
cheek.
• It has a pyramidal
form:
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The roots of the:
– First premolar tooth
– Second premolar
tooth
– Third molar tooth
– Canine tooth
(sometimes)
- Project into the
maxillary sinus
Tooth extraction can
produce a fistula.
Tooth infection can
produce sinusitis.
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MAXILLARY SINUS
The maxillary sinus opens in the middle meatus
through the semilunar hiatus.
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NERVE
SUPPLY
MAXILLARY
SINUS
• The mucous
membrane
of the
maxillary
sinus is
supplied by
the:
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– Superior
alveolar
and the
– Infraorbital
nerves. 30
FRONTAL SINUS
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The frontal sinuses (two) present within the frontal bone.
They are separated by a bony septum (frequently deviated to one
side).
Each sinus is roughly triangular.
It extends:
– Upward above the medial end of the eyebrow
– Backward into the medial part of the roof of the orbit.
• Each frontal sinus opens into the middle meatus
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SPHENOIDAL SINUSES
• They are two in number
• They lie within the body of the sphenoid bone.
• Each sinus opens into the sphenoethmoidal recess above
the superior concha.
• The mucous membrane is supplied by the posterior
ethmoidal nerves.
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ETHMOIDAL SINUSES
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They are contained within the ethmoid bone.
Only a thin layer of bone separates these sinuses from the orbit.
Infection can readily spread from the ethmoidal sinuses into the orbit.
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ETHMOIDAL SINUSES
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They are divided into three groups:
anterior, middle and posterior.
The anterior group drains in the
infundibulum.
The middle group drains in the middle
meatus (on or above bulla ethmoidalis).
The posterior group drains in the
superior meatus.
The mucous membrane of the
ethmoidal sinuses is supplied by
the anterior and posterior
ethmoidal nerves.
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Paranasal Sinuses and Their Site of
Drainage Into the Nose
Paranasal Sinuses and Their Site of Drainage Into the Nosea
Sinus
Site of Drainage
Maxillary sinus
Middle meatus through hiatus semilunaris
Frontal sinuses
Middle meatus via infundibulum
Sphenoidal sinuses
Ethmoidal sinuses
Sphenoethmoidal recess
Anterior group
Infundibulum and into middle meatus
Middle group
Middle meatus on or above bulla ethmoidalis
Posterior group
Superior meatus
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INFECTION OF THE NASAL
CAVITY (RHINITIS)
• Infection of the nasal
cavity may spread to:
– The paranasal
sinuses;
– Via the nasopharynx to
the auditory tube and
the middle ear;
– To the anterior cranial
fossa (via the
cribriform plate) – and
to produce meningitis.
NOSE BLEEDING (EPISTAXIS)
• The most common cause is nose picking.
• May be arterial or venous in origin.
• Often occurs from the anteroinferior
portion of the septum and involve the
septal branches of the sphenopalatine and
facial vessels.
INFECTION OF PARANASAL
SINUSES (SINUSITIS)
• A common complication of nasal
infection.
• Rarely, it could be a complication
of apical dental abscess (for the
maxillary sinus).
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