The nose has several important functions including respiration, olfaction, conditioning of inspired air, and protection of the lower airways. It has external and internal structures. The external nose consists of bone and cartilage while the internal nose includes nasal cavities divided by nasal conchae into passages that lead to paranasal sinuses. The nasal mucosa conditions air and supports smell. Olfactory neurons detect smells and relay signals to brain areas involved in processing odors.

1. FUNCTIONALANATOMY
OF THE
NOSE

2. GROUP MEMBERS
i. Ataryeba Henon
ii. Lekuru Charity
iii. Ndwadewazibwa Damalie
iv. Mbeiza Fazirah
v. Akoon Andrea
vi. Nalugya Grace Victoria
vii. Erima Timothy

3. WHAT IS THE NOSE?
•The nose is that part projecting above the mouth
on the face of a person or animal, in other wise the
most anterior protuberance of the face containing
the nostrils and used is for breathing and smelling.
It is a triangular pyramid with its base continuous
with the forehead and lower end is called apex or
tip of the nose.

4. ANATOMY OF NOSE
It consists of:
1. External nose
2. Nasal vestibule
3. Nasal cavity.
4.Paranasal Sinuses

5. FUNCTIONS OF NOSE
• Two important functions: Respiration. Olfaction. Minor function:
Aesthetics.
• It conditions inspired air i.e. filters, warms and humidifies.
• Imparts vocal resonance to the voice.
• Drains and clears the paranasal sinuses and lacrimal ducts.
• Protective function of lower airway: reflexes e.g. sneezing and mucus
secretions (pH 7). Lysozymes in nasal secretion also kill bacteria and
viruses. Mucociliary mechanism (nasal mucosa cilia beat constantly at a
speed of 5 to 10 mm per minute) and are in contact with serous layer of
mucous blanket and superficial layer of mucus which entraps the foreign
bodies, allergens and carry it to nasopharynx every 5 to 10 minutes.
• Air conditioning of air involves filtration and purification of inspired air
followed by regulation of its temperature by large surface area of nasal
mucosa and its humidification as required.

6. EXTERNAL NOSE
• The external nose varies considerably in size and shape, mainly
because of differences in the nasal cartilages, race and sex. The
dorsum of the nose extends from its superior angle (the root/
glabella) to the apex (tip) of the nose.
• The inferior surface of the nose is pierced by two piriform
openings (the anterior L. pear-shaped opening of the nasal cavity in
the skull), the nares (nostrils, anterior nasal apertures), which are
bound laterally by the alae (wings) of the nose and separated from
each other by the nasal septum.
• Lateral surfaces meet in the midline called bridge of nose.
• External nares on the inferior aspect of the nose are separated by
septum mobi nasi.

8. EXTERNAL NOSE
The external nose consists of the bony part and the cartilaginous part.
The bony part of the nose consists of the:
• Nasal bones.
• Frontal processes of the maxillae.
• Nasal part of the frontal bone and its nasal spine.
• Bony part of the nasal septum.
The cartilaginous part of the nose consists of five main cartilages:
• Two lateral cartilages
• Two U-shaped alar cartilages (free and movable; they dilate or constrict)
• Septal cartilage.

9. EXTERNAL NOSE
• These bony and cartilaginous portions are bound to each other
by fibrous tissue and by perichondrium and periosteum. Skin
on dorsum of nose is quite thin as compared to skin on alae
nasi.
• Muscles of external nose are procerus and nasalis consisting of
compressor and dilator naris. These muscles arise from the
fascia and are inserted into the skin. These muscles are supplied
by branches of facial nerve

11. Blood Supply of External Nose
• Alar and septal branches of facial artery.
• Dorsal nasal branch of ophthalmic artery.
• Infraorbital branch of maxillary artery
Drainage supply of the External Nose
• They drain into anterior facial and ophthalmic veins which
communicate with cavernous sinus.
Nerve Supply of the External Nose
• Infratrochlear and external nasal branch of ophthalmic nerve.
• Infraorbital branch of maxillary nerve.
Lymphatics
• They drain into submandibular and preauricular group of lymph
nodes.

12. NASAL VESTIBULE
• It is a skin-lined entrance to the nasal cavity containing hair
follicles, sebaceous glands, and sweat glands.
• It is bounded by alae nasi laterally and medially by septum mobi
nasi. The columella/columna separates two vestibules. Each
vestibule is limited above by limen nasi corresponding to the upper
border of major alar cartilage.

14. NASAL CAVITIES
• Communicates posteriorly with nasopharynx through posterior choanae.
• Has four walls, i.e. roof, floor, medial and lateral wall.
• The nasal mucosa is firmly bound to the periosteum and perichondrium
of the supporting bones and cartilages of the nose respectively. The
mucosa is continuous with the lining of all the chambers with which the
nasal cavities communicate:
• The nasopharynx posteriorly,
• The paranasal sinuses superiorly and laterally
• The lacrimal sac and conjunctiva superiorly.

15. NASAL CAVITIES
• The inferior two thirds of the nasal mucosa is the respiratory area, and
the superior one third is the olfactory area. is lined by ciliated
pseudostratified epithelium. Within the epithelium are interspersed
mucus-secreting goblet cells.
• Air passing over the respiratory area is warmed and moistened before it
passes through the rest of the upper respiratory tract to the lungs by the
rich blood capillary supply from the.
• The olfactory area is a specialized mucosa containing the peripheral
organ of smell; sniffing draws air to the area. The central processes of
the olfactory receptor neurons in the olfactory epithelium unite to form
nerve bundles that pass through the cribriform plate and enter the
olfactory bulb.

16. NASAL CAVITIES (ROOF)
• The roof of the nasal cavity is curved and narrow, except at the
posterior end; the roof is divided into three parts (frontonasal,
cribriform plate of ethmoid bone and sphenoidal), which are
named from the bones that form each part. Fractures to the roof
will cause the leakage of CSF a condition known as rhinorrhea.
It is composed of the olfactory mucous membrane which is
yellowish in colour and is limited to the superior concha, roof
of nasal cavity and the uppermost part of nasal septum. It is
composed of olfactory receptor cells, supporting cells, basal
cells and olfactory glands of Bowman.

18. NASAL CAVITIES (FLOOR)
• The floor of the nasal cavity is wider than the roof and it separates the nose from
the mouth. It is formed by the palate which is divided into soft and hard palate.
The hard palate is formed by the palatine process of the maxilla (premaxilla) and
the horizontal plate of the palatine bone.
• The soft palate is formed by 5 muscles namely;
Uvulae muscle, Levator veli palatine, Tensor veli palatine, Palatoglossus muscle,
and Palatopharyngeous muscle.
• The soft palate is composed of muscles and connective tissue which give it both
mobility and support. This palate is very flexible. When elevated for swallowing
and sucking, it completely blocks and separates the nasal cavity and nasal portion
of the pharynx from the mouth and the oral part of the pharynx. During sneezing,
it protects the nasal passage by diverting a portion of the excreted substance to
the mouth.

20. NASAL CAVITIES (MEDIAL WALL)
• Medial wall or the septum divides the nasal cavity into the left and
right sides. The medial wall has both a bony part and a
cartilaginous part that is to say, the bony part is formed by the
vomer and the vertical plate of the ethmoid bone, while the
cartilaginous part is formed by the septal cartilage.
• Blood Supply of Nasal Septum is by the external and internal
carotid system i.e. branches of sphenopalatine, branch of maxillary
artery, branches of greater palatine branch of maxillary and septal
branch of superior labial branch of facial artery. Internal carotid
system supplies through branches of ophthalmic artery, i.e. anterior
and posterior ethmoidal arteries.

22. NASAL CAVITIES (LATERAL WALL)
The lateral wall, made the nasal conchae/ turbinates i.e. superior, middle,
and inferior, three elevations that project/curve inferomedially, each
forming a roof for a meatus, or recess.
The nasal conchae divide the nasal cavity into four passages;
• Spheno-ethmoidal recess,
• Superior nasal meatus
• Middle nasal meatus
• Inferior nasal meatus.

25. NASAL CAVITIES (PASSAGES)
• The spheno-ethmoidal recess, (superoposterior to the superior concha)
receives opening of the sphenoidal air sinus.
• The superior nasal meatus is a narrow passage between the superior
and the middle nasal conchae (parts of the ethmoid bone) into which the
posterior ethmoidal sinuses open by one or more orifices.
• The inferior nasal meatus is a horizontal passage, inferolateral to the
inferior nasal concha (an independent, paired bone). It receives the
opening of nasolacrimal duct at junction of anterior one-third and
posterior two-thirds. This duct is guarded by a lacrimal fold called
Hasner’s valve (an imperfect valve).

26. NASAL CAVITIES (PASSAGES)
• The middle nasal meatus is longer and deeper than the superior
one. The anterosuperior part of this passage leads into the
ethmoidal infundibulum, an opening through which it
communicates with the frontal sinus, via the frontonasal duct. It lies
between middle and inferior turbinates and is important because of
presence of osteomeatal complex area in this meatus.
• The function of the conchae is to increase the surface area of the
nasal cavity – this increases the amount of inspired air that can
come into contact with the cavity walls. They also disrupt the fast,
laminar flow of the air, making it slow and turbulent. The air spends
longer in the nasal cavity, so that it can be humidified.

27. NASAL CAVITIES (OSTEOMEATAL
COMPLEX)
The various important landmarks in the osteomeatal (OM)
complex area are as follows:
• Uncinate process: It is a ridge of bone of ethmoidal labyrinth
which articulates with the ethmoidal process of inferior
turbinate. It partly covers the opening of the maxillary sinus
and forms lower boundary of hiatus semilunaris.
• Bulla ethmoidale (L. bubble): Is a rounded elevation located
superior to the semilunar hiatus. The bulla is formed by middle
ethmoidal cells, which constitute the ethmoidal sinuses and
open on or above it.

28. NASAL CAVITIES
(OSTEOMEATAL COMPLEX)
• Hiatus semilunaris: It is a space bounded above by bulla ethmoidale
and below and in front by uncinate process. Anterior ethmoids open into
it behind the opening of frontonasal duct which opens into anterior part
of the meatus. Opening of maxillary sinus lies below the bulla.
Accessory ostium of maxillary sinus in 40% cases lies below and behind
the hiatus semilunaris. The maxillary sinus also opens into the posterior
end of the semilunar hiatus.
Infundibulum: It is a short passage at the anterior end of hiatus semilunaris
and its average depth is 5 mm.

30. PARANASAL SINUSES
Are air-filled extensions of the respiratory part of the
nasal cavity into the following cranial bones: frontal,
ethmoid, sphenoid, and maxilla.
Function: Humidifying and warming inspired air,
Regulation of intranasal pressure, Increasing surface
area for olfaction, Lightening the skull, Resonance,
Absorbing shock, Contribute to facial growth.

31. PARANASAL SINUSES
•Is lined with Ciliated columnar and Non-cilliated
columnar cells epithelial cells which are interspersed
with goblet Cells that produce Glycoproteins (mucous)
hence increasing viscosity and elasticity.
•The secretions of the mucous membranes trap bacteria
and particulate matter. The cilia beat moving the mucous
toward the choane.

33. PARANASAL SINUSES (FRONTAL)
• The frontal sinuses are between the outer and the inner tables
of the frontal bone, posterior to the superciliary arches and the
root of the nose. Each sinus drains through a frontonasal duct
into the ethmoidal infundibulum, which opens into the
semilunar hiatus of the middle meatus. The frontal sinuses are
innervated by branches of the supraorbital nerves (Opthalmic
division of the trigeminal nerve).

34. PARANASAL SINUSES
(EHMOIDAL)
• The ethmoidal cells (sinuses) include several cavities that are located in
the lateral mass of the ethmoid bone between the nasal cavity and the
orbit. The anterior ethmoidal cells drain directly or indirectly into the
middle meatus through the infundibulum. The middle ethmoidal cells
open directly into the middle meatus. The posterior ethmoidal cells,
which form the ethmoidal bulla, open directly into the superior meatus.
The ethmoidal sinuses are supplied by the anterior and posterior
ethmoidal branches of the nasociliary nerves (Opthalmic division of the
trigeminal nerve).

35. PARANASAL SINUSES
(SPHENOIDAL)
• The sphenoidal sinuses, unevenly divided and separated by a
bony septum, occupy the body of the sphenoid bone; they may
extend into the wings of this bone in the elderly. Because of
these sinuses, the body of the sphenoid is fragile. Only thin
plates of bone separate the sinuses from several important
structures: the optic nerves and optic chiasm, the pituitary
gland, the internal carotid arteries, and the cavernous sinuses.
The posterior ethmoidal artery and nerve supply the sphenoidal
sinuses.

36. PARANASAL SINUSES
(MAXILLARY)
• The maxillary sinuses are the largest of the paranasal sinuses.
These large pyramidal cavities occupy the bodies of the maxillae.
• The apex of the maxillary sinus extends toward and often into the
zygomatic bone.
• The base of the maxillary sinus forms the inferior part of the
lateral wall of the nasal cavity.
• The roof of the maxillary sinus is formed by the floor of the orbit.
• The floor of the maxillary sinus is formed by the alveolar part of
the maxilla. The roots of the maxillary teeth, particularly the first
two molars, often produce conical elevations in the floor of the
maxillary sinus.

37. PARANASAL SINUSES
(MAXILLARY)
• Each sinus drains by an opening, the maxillary ostium, into
the middle meatus of the nasal cavity by way of the semilunar
hiatus. Because of the superior location of this opening, it is
impossible for the sinus to drain when the head is erect until the
sinus is full. The arterial supply of the maxillary sinus is mainly
from superior alveolar branches of the maxillary artery;
however, branches of the greater palatine artery supply the
floor of the sinus. Innervation of the maxillary sinus is from the
anterior, middle, and posterior superior alveolar nerves,
branches of (Maxillary branch of the Trigeminal nerve).

38. MUCOUS MEMBRANE OF NOSE
• It is the thickest and very vascular over nasal turbinates and very
thin in the meatuses. It is pseudostratified ciliated columnar type of
epithelium with goblet cells, mucous and serous glands.
• The nerve supply of the posteroinferior half to two thirds of the
nasal mucosa is chiefly from Maxillary nerve by way of the
nasopalatine nerve to the nasal septum and posterior lateral nasal
branches of the greater palatine nerve to the lateral wall. The
anterosuperior part of the nasal mucosa (both the septum and lateral
wall) is supplied by the anterior ethmoidal nerves, branches of
Ophthalmic nerve. The lymphatic drainage is by the submandibular
and deep cervical lymph nodes.

39. OLFACTORY FUNCTION
These first order neurons are twenty in number, pass through
cribriform plate of ethmoid and end in olfactory bulb which
conveys secondary olfactory neurons to olfactory tract. It further
relays it to anterior perforated substance, amygdaloid nucleus
and area piriformis. Here, the tertiary olfactory neurons arise
which travel to hippocampal formation which relays to
paraterminal gyrus, then to the fornix and, hence, to nucleus
habenular and mammillary body in thalamus.

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