2. NOSE (Rhinos-Greek)
■ It is the uppermost part of the RT & contains
the peripheral organ of smell.
■ It consists of external nose & nasal cavity.
■ The functions of the nose are:
1. Respiration.
2. Olfaction.
3. Protection of the lower respiratory
passages.
4. Air conditioning of the inspired air.
5. Vocal resonance.
6. Nasal reflex functions (e.g., sneezing).
7. Central role of the nose in facial
appearance !!!
18 February 2023 Human Anatomy James Mwangi K
3. External Nose: Structure
■ Nose consists of bony & cartilaginous
framework
■ Formed above by the:
• Nasal bones
• Frontal processes of maxillae
• Nasal part of frontal bone
■ Formed below by the:
• Plates of hyaline cartilage, which
include upper & lower nasal
cartilages and the septal cartilage
4. Nasal Cavity
■ Extends from the external
(anterior) nares to the posterior
nares (choanae)
■ Divided into right & left halves by
the nasal septum
■ Each half has a:
Floor
Roof
Lateral wall
Medial wall (septum)
5. ■ Roof
■ Is narrow & formed (from behind
forward) by the:
• Body of sphenoid
• Cribriform plate of ethmoid bone
• Frontal bone
• Nasal bone & cartilage
■ Floor
• Separates it from the oral cavity
• Formed by the hard (bony)
palate
6. ■ Medial Wall (Nasal Septum)
■ Osteocartilaginous partition, only
rarely lying in the midline
■ Covered by the mucoperiosteum
■ Formed:
Superiorly by the vertical
(perpendicular) plate of ethmoid
bone
Posteriorly by the vomer bone
Anteriorly by the septal cartilage
7. ■ Lateral Wall
■ Shows 3 horizontal bony projections,
covered by mucous membrane, the
superior, middle & inferior conchae
(turbinates)
■ The superior & middle conchae are
parts of the ethmoid bone, whereas
the inferior concha is a separate bone
■ The cavity below each concha is
called a meatus and are named as
superior, middle & inferior
corresponding to the conchae
8. ■ The small space above the superior
concha is called the
sphenoethmoidal recess
• The middle meatus is continuous in
front with a depression called the
atrium
• Atrium is limited above by a ridge
called agar nasi
• Below and in front of atrium, and just
within the nostril lies the vestibule
9. ■ The conchae increase the
surface area of the nasal cavity
■ The recess & meati receive the
openings of the:
Paranasal sinuses
Nasolacrimal duct
10. ■ Sphenoethmoidal recess:
Receives the opening of the
sphenoidal sinus
■ Superior meatus: Receives the
opening of the posterior
ethmoidal sinus
■ Inferior meatus: Receives the
opening of the nasolacrimal duct.
The opening is guarded by a
valve, a fold of mucous
membrane
11. ■ Middle meatus:
• Shows a rounded eminence, the
ethmoidal bulla, caused by the bulging
of the underlying middle ethmoidal
sinus, which opens on its upper border.
• A curved groove, hiatus semilunaris,
lies below the bulla. Hiatus receives
the opening of the maxillary sinus
• Anterior end of hiatus leads to funnel-
shaped infundibulum, which receives
the openings of the frontal & the
anterior ethmoidal sinuses
12. Lining of the Nasal Cavity
■ Vestibule is lined by modified skin,
and has short, curved hair called
vibrissae
■ The roof, upper part of the septum,
upper surface of the superior concha,
and the sphenoethmoidal recess are
lined by the olfactory mucosa
■ The rest of the cavity is lined by the
respiratory mucosa
V
V
A
13. Olfactory Mucosa
■ Contains olfactory cells (bipolar sensory ganglion
cells), which serve as receptors for olfactory stimuli.
■ Distinct smells are far more numerous than tastes
■ The sense of smell plays a major role in the flavor of
foods and it is common for individuals who lose their
sense of smell to report that food loses its taste. (food
seems somewhat tasteless when a person has cold)
■ Most air breathed in normally flows through the nose
but only a small part reaches the olfactory mucosa,
enough to get a response to an odor. Sniffing,
however, increases the flow of air over the smell
receptor cells, greatly increasing their exposure to
odors.
14. Respiratory Mucosa
■ Pseudostratified ciliated columnar
epithelium with goblet cells
■ Rests on thick network of thin walled
veins that warms the air as it flows
through the cavity
■ Glands produce ‘mucus’, which:
moisten the air
cleans the air by trapping the
incoming bacteria and foreign
debris
■ Cilia help in moving the contaminated
mucus posteriorly towards the throat,
where it is swallowed and digested by
the stomach juices
15. Nerve Supply
■ Nasal cavity receives sensory &
visceral innervation
Sensory innervation
■ Olfactory mucosa supplied by olfactory
nerves
■ Nerves of general sensation are derived
from opthalmic & maxillary nerves
Anterior part supplied by the
anterior ethmoidal nerve (branch of
opthalmic nerve)
Posterior part supplied by nasal,
nasopalatine and palatine branches
(of maxillary nerve)
16. Visceral Innervation
■ Sympathetic fibers arise from
neurons of superior cervical ganglion
and are distributed through plexuses
around the arteries, supply mainly
vascular smooth muscle
■ Parasympathetic fibers arise from
neurons of the pterygopalatine
ganglion that course in the
nasopalatine nerve (branch of
maxillary) and its branches, supply
the mucosal glands.
17. Arterial Supply
■ Sphenopalatine artery (branch of the
maxillary artery) is the main supply
■ Alar and septal branches of superior
labial artery (branch of the facial artery)
■ Anterior & posterior ethmoidal arteries
(branches of the ophthalmic artery)
■ The arteries make a rich anastomosis
in the region of the vestibule, and
anterior portion of the septum
18. Venous Drainage:
■ Veins begin as a rich plexus in the submucosa, accompany the
corresponding arteries, and drain into the facial, ophthalmic, and
sphenopalatine veins.
Lymphatic Drainage:
■ The lymphatics from the:
Vestibule drain into the submandibular lymph nodes
Rest of the cavity drains into the upper deep cervical lymph nodes
19. Paranasal Sinuses
■ Air filled cavities located in the bones
around the nasal cavity: ethmoid,
sphenoid, frontal bones & maxillae
■ Lined by respiratory mucosa which is
continuous with the mucosa of the nasal
cavity
■ Drain into the nasal cavity through
relatively small apertures
■ Drainage of the sinuses mainly depends
on the movement of the cilia, which
propel the mucus toward their openings
in the nasal cavity
20. ■ The development of sinuses begins in 3-
4 month, but only maxillary & ethmoid
sinuses are present in rudimentary form
at birth. The frontal & sphenoidal sinuses
are not clinically perceptible at birth and
can rarely be demonstrated on plain x-
ray before two years of age.
■ Continue to grow postnatally
■ Enlarge appreciably after 8th year &
become fully formed at adolescence
M
E
From a 3 months old fetus, showing
ethmoid & maxillary sinuses
21. Functions of Paranasal Air Sinuses
■ Lighten the skull
■ Act as resonant chambers for speech
■ The respiratory mucosal lining helps in warming, cleaning and
moistening the incoming air
22. Maxillary Sinuses
• Located within the body of the maxilla
• Pyramidal in shape with the base forming
the lateral wall of nose & the apex lies in
the zygomatic process of the maxilla
• Roof: formed by the floor of the orbit
• Floor: formed by the alveolar border.
Roots of 1st and 2nd premolars and the
3rd molar (sometimes canines) project
into the sinus
• Opens into the middle meatus through
the hiatus semilunaris
• Supplied by superior alveolar &
infraorbital nerves
23. Frontal Sinuses
■ Two in number
■ Located within the frontal bone,
separated from each other by a
bony septum
■ Triangular in shape, extending
backward into the roof of the orbit
■ Opens into the middle meatus
through the infundibulum
■ Supplied by the supraorbital nerve
24. Ethmoidal Sinuses
■ Located within the ethmoid
bone, between the nose
and the orbit
■ Divided into three groups:
anterior, middle & posterior
■ Anterior group opens into
the infundibulum, middle
opens on the bulla, and
posterior into the superior
meatus
■ Supplied by the anterior
and posterior ethmoidal
nerves
25. Sphenoidal Sinuses
■ Two in number
■ Located within the body of
sphenoid
■ Open into the sphenoethmoidal
recess
■ Supplied by the posterior
ethmoidal nerve
26. Clinical Correlates
■ Epistaxis: Little’s area, common site
of bleeding from nose
■ Inflammation of the nasal mucosa,
Rhinitis, results in nasal congestion
and excessive production of mucus
leading to ‘postnasal drip’
■ Infections of the nasal cavity can
extend to the:
Paranasal sinuses
Nasolacrimal duct & lacrimal sac
27. ■ Inflammation of mucosa of the sinuses,
Sinusitis, causes excessive production of
mucus leading to obstruction of the drainage
of sinuses. This results in headache and
change in the voice
■ Infection of frontal & anterior ethmoidal
sinus can easily spread to maxillary sinus
because of the location of their openings
■ Infection of upper teeth can lead to
inflammation of the maxillary sinus
■ Extraction of an infected upper tooth may
result in a fistula
28. ■ The maxillary sinus is most
commonly the site of infection
■ The inflamed mucosa results in
excessive production of mucus as
well as narrowing of its opening in
the nasal cavity
■ The position of the drain causes
problems in that mucus can collect in
the sinus below the drain. In this
situation, the sinus will only drain if
the patient lies on their opposite side.
■ Pressure from the trapped
fluid/mucus causes sinus pain
29. 18 February 2023 Human Anatomy James Mwangi K
• It is the inflammation of mucus membrane lining the nasal cavity.
• The hypertrophy of mucosa over inferior concha is a common feature of
allergic rhinitis.
• Clinically it presents as: nasal blockage, sneezing, and water discharge from
nose (rhinorrhea).
• The excessive rhinorrhea due to vasomotor and allergic rhinitis can be
controlled by sectioning the Vidian nerve
Rhinitis:
Frontal sinusitis
