The nasal cavity is pyramidal in shape with an osteo-cartilaginous framework covered by muscles and skin. It is divided into right and left cavities by the nasal septum. Each cavity communicates with the exterior through the naris and with the nasopharynx through the posterior nasal aperture. The lateral wall contains three nasal conchae which divide the cavity into superior, middle, and inferior meatuses that contain openings for sinuses and other structures. The roof and floor are formed by bones with the nasal septum dividing the cavity into two.

1. -R.Vignesh

2. • Pyramidal in shape
• Root up and base
directed
downwards
• Consists of osteo
cartilaginous
framework
covered by
muscles and skin

3. • Upper1/3-bony
• lower2/3-
cartilaginous

5. • Upper lateral cartilage
• Lower lateral cartilage
• Sesamoid cartilage
• septal cartilage

7. • Thin and freely mobile over nasal bones and upper
lateral cartilage
• Thick and adherent over alar cartilage
• Contains many sebaceous glands

8. • Divided into right and left nasal cavities by nasal
septum
• Each nasal cavity communicates
• -with the exterior through naris or nostril
-with the nasopharynx through posterior
nasal aperture or the choana.

9. • Anterior and inferior part
of nasal cavity is called
vestibule.
• Its upper limit on the
lateral wall is marked by
limen nasi (also called
nasal valve).

10. • Lateral
wall
• Medial
wall
• Roof
• Floor

12.  The lateral wall has three projections (occasionally
4)of bone called the superior, middle, and inferior
nasal conchae
 The space below each concha is called a meatus

14.  The inferior meatus lies below the inferior
concha
 It receives the opening of the lower end of the
nasolacrimal duct, which is guarded by a fold
of mucous membrane(hasner's valve)

16.  The middle meatus lies below the middle concha
 It has a rounded swelling called the bulla
ethmoidalis that is formed by the middle ethmoidal
air sinuses, which open on its upper border
 posterosuperior border of uncinate process is sharp
and runs parallel to anterior border of bulla
ethmoidalis;
 the gap between the two is called hiatus
semilunaris
 anterior ethmoidal cells and frontal and maxillary
sinuses into the middle meatus

18.  The superior meatus lies below the superior
concha
 It receives the openings of the posterior ethmoid
sinuses

19.  The sphenoethmoidal recess is a small area
above the superior concha
 It receives the opening of the sphenoid airsinus

22.  Nasal septum consists of three parts:
 1. Columellar septum
 2. Membranous septum
 3. Septum proper
 (a) the perpendicular plate of ethmoid,
 (b) the vomer and
 (c) a large septal (quadrilateral) cartilage

24. • ROOF -Anterior sloping part of the roof is formed
by nasal bones, posterior sloping part is formed by
the body of sphenoid bone and 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 and horizontal
part of the palatine bone in its posterior one-
fourth.

25.  The olfactory nerves from the olfactorymucous
membrane
 The nerves of ordinary sensation
 (a) Anterior ethmoidal nerve.
 (b) Branches of sphenopalatine ganglion.
 (c) Branches of infraorbital nerve.They supply
vestibule of nose both on its medial and lateral
side.
 Autonomic- Vidian nerve

27.  NASAL SEPTUM
 INTERNAL CAROTID SYSTEM
 1. Anterior ethmoidal artery
 2. Posterior ethmoidal artery
 EXTERNAL CAROTID SYSTEM
 1. Sphenopalatine artery (branch of maxillary
artery) gives nasopalatine and posterior medial
nasal branches.
 2. Septal branch of greater palatine artery
(branch of maxillary artery).
 3. Septal branch of superior labial artery
(branch of facial artery).

28. • LATERAL WALL
• INTERNAL CAROTID SYSTEM
• 1.Anterior ethmoidal
• 2.Posterior ethmoidal
• EXTERNAL CAROTID SYSTEM
• 1. Posterior lateral nasal branches
• 2. Greater palatine artery
• 3. Nasal branch of anterior superior dental
• 4. Branches of facial artery to nasal vestibule

30.  Lymphatics from the external nose and anterior
part of nasal cavity drain into submandibular
lymph nodes
 Those from the rest of nasal cavity drain into
upper jugular nodes

32. • It lies behind the nasal cavities and extends from
the base of skull to the soft palate or the level of
the horizontal plane passing through the hard
palate
• Roof of the nasopharynx is formed by basisphenoid
and basiocciput.
• Posterior wall is formed by arch of the atlas
vertebra
• Floor is formed by the soft palate anteriorly but is
deficient posteriorly

33. • Anterior wall is formed by posterior nasal
apertures or choanae
• Lateral wall. Each lateral wall presents the
pharyngeal opening of eustachian tube,torus
tubarius,fossa of rosenmuller, salphingo pharyngeal
fold

34. • ADENOID-subepithelial collection of lymphoid
tissue at the junction of roof and posterior wall of
nasopharynx

35. • PASSAVANT’S RIDGE -a mucosal ridge raised by
fibres of palatopharyngeus.
• SINUS OF MORGAGNI-is a space between the base
of the skull and upper free border of superior
constrictor muscle