2. • Development of Nose and Paranasal Sinuses
• The nose develop from the frontonasal process which grows between
the primitive forebrain and stomodium.
• The frontonasal process gets divided into median nasal process and two
lateral processes.
• Primitive nasal cavities are closed at their posterior ends by bucconasal
membrane which rupture and forms posterior naries. If it fails to rupture,
it can result in choanal atresia.
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4. THE EXTERNAL NOSE
Bony upper one third (Three bones):
a) Nasal bones.
b) Maxillary process of the frontal bone.
c) Frontal process of the maxilla.
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5. Cartilagenous lower two thirds
a)Upper lateral cartilages.
b) Lower lateral (alar) cartilage.
c)Lesser alar cartilages.
d) Cartilage of the nasal septum in between.
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6. The nose is divided into two cavities separated by the nasal septum.
The anterior nares (nostrils) separated by the columella.
The posterior nares (choanae) separated by the posterior edge of the vomer.
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7. Walls of the nasal cavities:
• Lateral wall of the nose
Three bony projections called conchae or turbinates and three meatuses
1. Superior meatus: drains the posterior ethmoidal sinuses.
2. Middle meatus: (osteomeatal complex), drains the:
a) Frontal sinus anteriorly.
b) Maxillary sinus posteriorly.
c) Anterior ethmoidal sinuse.
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8. • 3.Inferior meatus: drains the naso-lacrimal duct.
Spheno-ethmoidal recess: is a recess above the superior concha and
drains the sphenoidal sinus.
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10. Medial wall:
1. Quadrilateral cartilage,
anteroinferiorly.
2. Perpendicular plate of ethmoid,
superiorly.
3. The vomer bone,
postero-inferiorly.
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11. Roof
• Anterior sloping part of the roof is formed by nasal bones,
• posterior sloping part is formed by the body of sphenoid bone
• the middle horizontal part is formed by the cribriform plate of ethmoid
Floor
• It is formed by palatine process of the maxilla in its anterior three-fourths
• horizontal part of the palatine bone in its posterior one-fourth.
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12. Lining epithelium
• The vestibule anteriorly is lined with skin.
• The olfactory area (superior 1/3) is lined with olfactory epithelium with
bipolar neurons.
• The respiratory area (rest of the nasal cavity) is lined with pseudostratified
columnar ciliated epithelium
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13. Blood supply of the nose:
The nose is supplied by branches from the internal carotid artery (ICA) above
the middle turbinate and branches from the external carotid artery (ECA)
below the middle turbinate.
1.Anterior and posterior ethmoidal arteries of ophthalmic artery of ICA.
2. Sphenopalatine and greater palatine arteries of maxillary artery of ECA.
3. Superior labial artery of facial artery of ECA. 13
14. The Little’s area
• It lies in the anterior part of the nasal septum where branches from
ICA & ECA anastomose to form the KIESSELBACH’S PLEXUS.
1. Anterior ethmoidal artery of ICA.
2. Sphenopalatine artery of ECA.
3. Greater palatine artery of ECA.
4. Superior labial artery of ECA.
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16. Venous drainage of the nose:
• The nose drains into facial and ophthalmic veins anteriorly and into
pterygoid plexus posteriorly.
• The nose is considered a dangerous area because it communicates
with:
The cavernous sinus via ophthalmic vein.
The superior sagittal sinus via foramen caecum.
Veins of the frontal lobe of the brain via cribriform plate.
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18. Nerve supply of the nose:
• Olfaction: olfactory nerve to olfactory mucosa.
• Sensory: branches from trigeminal nerve: anterior ethmoidal of
ophthalmic nerve, sphenopalatine and greater palatine of maxillary
nerve.
• Autonomic: sympathetic from deep petrosal nerve and
parasympathetic from facial nerve (superficial petrosal) to form the
vidian nerve to sphenopalatine nerve to the nasal mucosa.
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20. LYMPHATIC DRAINAGE
Lymphatics from the external nose and anterior part of nasal cavity drain into
submandibular lymph nodes and the rest of nasal cavity drain into upper jugular
nodes either directly or through the retropharyngeal nodes.
Lymphatics of the upper part of nasal cavity communicate with subarachnoid
space along the olfactory nerves.
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21. Anatomy of the paranasal sinuses
Air filled cavities, 4 on each side, lined by pseudostratified columnar
ciliated epithelium.
Anterior group: frontal, maxillary and anterior ethmoid sinuses.
Posterior group: posterior ethmoid and sphenoid sinuses.
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23. FUNCTIONS OF PARANASAL SINUSES
1. Air-conditioning of the inspired air
2. To provide resonance to voice.
3. To act as thermal insulators
4. To lighten the skull bones.
5. To provide extended surface for olfaction;
6. To provide local immunologic defence against microbes.
7. To act as buffers against
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25. Maxillary Sinus (Antrum of Highmore)
It is the largest of paranasal sinuses and occupies the body of maxilla.
It is pyramidal in shape with base towards lateral wall of nose and apex
directed laterally into the zygomatic process of maxilla.
On an average, maxillary sinus has a capacity of 15 mL in an adult.
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26. Relations
Anterior wall -facial surface of maxilla and soft tissues of cheek.
Posterior wall - infratemporal and pterygopalatine fossae.
Medial wall -the middle and inferior turbinates and meatuses,
Floor -alveolar and palatine processes of the maxilla and
the roots of second premolar and first molar teeth.
Roof -the floor of the orbit.
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28. Ethmoid sinus
They are 3-18 thin wall air cells between the orbit and nasal cavity. The
anterior ethmoids drain into the middle meatus while the posterior ethmoid
drains into the superior meatus
-Roof: anterior cranial fossa.
-Floor: maxillary sinus.
-Medially: middle turbinate.
-Laterally: orbit, separated from it by thin plate of bone (lamina papyracea)
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29. Frontal sinus
Each frontal sinus is situated between the inner and outer tables of
frontal bone, above and deep to the supraorbital margin.
It varies in shape and size and is often loculated by incomplete septa.
Anterior wall -the skin over the forehead
Inferior wall -the orbit and its contents;
Posterior wall -the meninges and frontal lobe of the brain.
It drains through middle meatus by the frontonasal duct
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30. Sphenoid Sinus
It occupies the body of sphenoid.
The two, right and left sinuses, are rarely symmetrical and are separated
by a thin bony septum.
Ostium of the sphenoid sinus opens into the sphenoethmoidal recess,
medial to the superior turbinate.
In adults, it is situated about 1.5 cm from the upper border of choana.
The average distance from the anterior nasal spine to the ostium is about
7 cm.
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32. Relations of the Sphenoid Sinus
Lateral wall-the optic nerve and carotid artery and maxillary nerve
Floor -Vidian nerve.
Roof - Anterior part is related to the olfactory tract, optic chiasma
and frontal lobe,
-Posterior part is related to the pituitary gland
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34. MUCOUS MEMBRANE OF PARANASAL SINUSES
Paranasal sinuses are lined by mucous membrane which is continuous
with that of the nasal cavity through the ostia of sinuses. It is thinner and
less vascular.
Histologically, it is ciliated columnar epithelium with goblet cells which
secrete mucus.
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35. LYMPHATIC DRAINAGE
The lymphatics of maxillary, ethmoid, frontal and sphenoid sinuses form a
capillary network in their lining mucosa and collect with lymphatics of
nasal cavity.
Then they drain into lateral retropharyngeal and/or jugulodigastric nodes.
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