1. NASAL CAVITY AND PARANASAL SINUSES
Dr. Vohra

2. THE NOSE

3. THE NOSE 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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4. THE NOSE
The nostrils are bounded laterally by the alla.
Dr. Vohra

5. 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 by hyaline carilages:
Upper nasal cartilages
Lower nasal cartilages
Septal catilage
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6. 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

7. BOUNDARIES NERVE SUPPLY BLOOD SUPPLY LYMPH DRAINAGE
NASAL CAVITY
BOUNDARIES
NERVE SUPPLY
BLOOD SUPPLY
LYMPH DRAINAGE

8. 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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9. 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, from behind forward, by:
The body of the sphenoid
The cribriform plate of the ethmoid
The frontal bone
The nasal bone
The nasal cartilages
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10. 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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11. 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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12. 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.
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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13. 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 is caused by the bulging of the underlying middle ethmoidal air sinuses, which open on its upper border.
Hiatus semilunaris is a curved cleft below the bulla.
It leads into a funnel-shaped channel called the infundibulum
The frontal sinus opens into and is continuous with the infundibulum.
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14. 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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15. 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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16. 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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17. 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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18. 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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19. 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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20. 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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21. 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 (CnV2) of the trigeminal nerve
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22. 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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23. 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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24. MAXILLARY FRONTAL SPHENOIDAL ETHMOIDAL
PARANASAL SINUSES
MAXILLARY
FRONTAL
SPHENOIDAL
ETHMOIDAL

25. DEFINITION They are cavities inside the: They are: Maxilla
Frontal bone
Sphenoid bone
Ethmoid bone
They are:
Lined with mucoperiosteum;
Filled with air;
Communicate with the nasal cavity.
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26. Functions of the Paranasal Sinuses
Reduce the weight of the skull.
Resonators of the voice.
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27. 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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28. MAXILLARY SINUS
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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29. MAXILLARY SINUS The maxillary sinus opens in the middle meatus
through the semilunar hiatus.
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30. 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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31. FRONTAL SINUS Each frontal sinus opens into the middle meatus
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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32. 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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33. 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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34. ETHMOIDAL SINUSES
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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35. 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
Sphenoethmoidal recess
Ethmoidal sinuses
    Anterior group
Infundibulum and into middle meatus
    Middle group
Middle meatus on or above bulla ethmoidalis
    Posterior group
Superior meatus
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36. 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.

37. 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.

38. 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).

39. Thank you