Transcript 22.NASAL CAVITY AND PARANASAL SINUSES.ppt
NASAL CAVITY AND PARANASAL SINUSES
Dr. Vohra
THE NOSE
THE NOSE
Dr. Vohra • • • 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
Dr. Vohra The nostrils are bounded laterally by the
alla.
4
Dr. Vohra
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
Below
carilages: – by hyaline
Upper nasal cartilages
–
Lower nasal cartilages
–
Septal catilage
5
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
Dr. Vohra
BOUNDARIES
• From the
nostrils
in front • to the
choanae
behind • Divided into right and left half by the
nasal septum
• Each half has: – – – –
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
The roof – – – – – is narrow and it is formed,
The body of the sphenoid The cribriform plate of the ethmoid The frontal bone The nasal bone The nasal cartilages
Dr. Vohra
from behind forward
, by: 9
The lateral wall of the nose
•
The lateral wall
has three projections called the: –
Superior concha
–
Middle concha
–
Inferior concha
• The area called a
below
each concha is
meatus
.
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The lateral wall of the nose
Dr. Vohra • The area called a
below
each concha is
meatus
.
–
Superior meatus
–
Middle meatus
–
Inferior meatus
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Openings in the Superior Meatus
•
The sphenoethmoidal recess
lies anterior to the body of the sphenoid bone.
– It receives the opening of the
sphenoidal air sinus
.
Dr. Vohra •
The superior meatus
lies
below and lateral
to the superior concha.
– It receives the openings of the
posterior ethmoidal air sinuses
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Openings in the Middle Meatus
• •
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 air sinuses ,
is caused by the bulging of the underlying which open on its upper border.
middle ethmoidal Hiatus semilunaris
is a curved cleft below the bulla.
– It leads into a funnel-shaped channel called the
infundibulum
–
The frontal sinus
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Openings in the Middle Meatus • •
The maxillary sinus
hiatus semilunaris.
opens in the middle meatus via
The anterior ethmoidal sinuses
infundibulum.
also open in the Dr. Vohra 14
Structures related to the middle meatus • • • • 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
• • 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 recess.
lateral wall
, it lines the upper surface of the superior concha and the spheno-ethmoidal • On the
medial wall
, it lines the superior part of the nasal septum.
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RESPIRATORY MUCOSA
• 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 olfactory nerve cells
.
arise from the central axons of the • 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 21
• • • •
ARTERIAL BLOOD SUPPLY
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 Dr. Vohra • 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
Dr. Vohra • They are
cavities
inside the: – 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 Dr. Vohra • • • • • It is located within the body of the maxilla behind the skin of the cheek.
• It has a
pyramidal form:
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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Dr. Vohra NERVE SUPPLY MAXILLARY SINUS • The mucous membrane of the maxillary sinus is supplied by the: –
Superior alveolar
and the –
Infraorbital nerves
.
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FRONTAL SINUS • • The
frontal sinuses
(two) present within the frontal bone.
They are separated by a
bony septum
side).
(frequently deviated to one • • 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 Dr. Vohra 31
SPHENOIDAL SINUSES
• They are two in number • They lie within the body of the
sphenoid bone
.
• Each sinus opens into the
sphenoethmoidal recess
the superior concha.
• The mucous membrane is supplied by the
posterior ethmoidal nerves.
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ETHMOIDAL SINUSES
• • • 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
• • • • They are divided into three groups: anterior, middle and posterior.
The
anterior group
infundibulum.
drains in the The
middle group
drains in the middle meatus (on or above bulla ethmoidalis).
The
posterior group
superior meatus.
drains in the Dr. Vohra 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 Nose
a
Sinus Maxillary sinus Site of Drainage
Middle meatus through hiatus semilunaris
Frontal sinuses
Middle meatus via infundibulum
Sphenoidal sinuses Ethmoidal sinuses
Anterior group Sphenoethmoidal recess Infundibulum and into middle meatus Middle group Posterior group Middle meatus on or above bulla ethmoidalis Superior meatus Dr. Vohra 35
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).