Uppermost parts of the respiratory tract and contain the olfactory receptors
Elongated wedge-shaped spaces with a large inferior base and a narrow superior apex
Skeletal framework consisting mainly of bone and cartilage
Nares – external opening of nose
Choanae - open into the nasopharynx
Bones that contribute to the skeletal framework of the nasal cavities include
Unpaired: ethmoid, sphenoid, frontal bone, and vomer;
Paired: nasal, maxillary, palatine and lacrimal bones, and inferior conchae
3. NASAL CAVITIES
• Uppermost parts of the
respiratory tract and contain
the olfactory receptors
• Elongated wedge-shaped
spaces with a large inferior
base and a narrow superior
apex
• Skeletal framework consisting
mainly of bone and cartilage
– Nares – external opening of
nose
– Choanae - open into the
nasopharynx
4. Skeletal framework
• Bones that contribute to the skeletal framework of the nasal
cavities include
– Unpaired: ethmoid, sphenoid, frontal bone, and vomer;
– Paired: nasal, maxillary, palatine and lacrimal bones, and
inferior conchae
6. External nose
• Pyramidal in shape with its apex
anterior in position
• Composed partly of bone and
mainly of cartilage
– Bony parts - continuous with
the skull bones and parts of the
maxillae and frontal bones
– Cartilaginous Part - anteriorly,
and on each side
• Laterally - lateral processes
of the septal cartilage,
major alar and three or four
minor alar cartilages
• Single septal cartilage in the
midline that forms the
anterior part of the nasal
septum
9. NASAL CAVITIES
• The nasal cavities are separated
- each other by a midline nasal
septum
• Oral cavity below by the hard
palate
• Cranial cavity above by parts of
the frontal, ethmoid and
sphenoid bones
• Each nasal cavity has a floor,
roof, medial wall, and lateral
wall.
10. Lateral wall
• Characterized by three curved shelves of bone (conchae)
• One above the other and project medially and inferiorly across the nasal
cavity
• The medial, anterior, and posterior margins of the conchae are free
• Increase the surface area of contact between tissues of the lateral wall
and the respired air
• Openings of the paranasal sinuses, which are extensions of the nasal
cavity
• Opening of the nasolacrimal duct
11.
12. Lateral wall
Conchae divide each nasal cavity into four air channels
• Inferior nasal meatus between the inferior concha and the nasal floor
• Middle nasal meatus between the inferior and middle concha
• Superior nasal meatus between the middle and superior concha
• Spheno-ethmoidal recess between the superior concha and the nasal roof
15. Floor
• Smooth, concave, and much wider than the roof
• It consists of
– Soft tissues of the external nose;
– Upper surface of the palatine process of the maxilla,
– Horizontal plate of the palatine bone, which together form the
hard palate
• Naris opens anteriorly into the floor,
• Superior aperture of the incisive canal - deep to the mucosa
– immediately lateral to the nasal septum
17. Roof
• Narrow and is highest in central regions where it is formed by the
cribriform plate of the ethmoid bone
• Anterior to the cribriform plate - roof slopes inferiorly to the nares and
consist
– nasal spine of the frontal bone and the nasal bones
– lateral processes of the septal cartilage and major alar cartilages
• Posteriorly, the roof slopes inferiorly to the choanae and is formed by
– Anterior surface of the sphenoid bone;
– Ala of the vomer
– Medial plate of the pterygoid process.
19. Regions of Nasal Cavities
• Each nasal cavity consists of three general regions
• Nasal vestibule
– small dilated space just internal to the naris that is lined
by skin and contains hair follicles
• Respiratory region
– Largest part of the nasal cavity
– Rich neurovascular supply
– Lined by respiratory epithelium composed mainly of
ciliated and mucous cells
• Olfactory region
– small, is at the apex of each nasal cavity
– Lined by olfactory epithelium which contains the
olfactory receptors
21. FunctionsofNasalCavities
• Main: housing receptors for the sense of smell
(olfaction)
• Accessory
– Adjust the temperature and humidity of respired air -
action of a rich blood supply,
– Trap and remove particulate matter - hair in the
vestibule
– Capturing foreign material in abundant mucus.
– Mucus normally is moved posteriorly by cilia on
epithelial cells in the nasal cavities and is swallowed
22. Lymphatics
• Anterior regions
– drains forward onto
the face by passing
around the margins of
the nares -
submandibular nodes
• Posterior regions of
the nasal cavity and
the paranasal sinuses
– drains into upper
deep cervical nodes
through the
retropharyngeal
nodes
