Anatomy of the Nose and Paranasal sinuses

1. ANATOMY OF THE NOSE
AND
PARANASAL SINUSES
Presenter
Dr. Maxprince - MD, Resident

2. Outline
1. Introduction.
2. Embryology of the Nose and Paranasal sinuses.
3. Growth Anatomy of the Nose and Paranasal sinuses.
4. Functions of the Nose and Paranasal sinuses.
5. Anatomic variations.
6. Clinical application.
7. References

3. 1. NOSE

4. 1. Introduction.
The human nose is the most protruding part
of the face.
It bears the nostrils and is the first organ of
the respiratory.
It is also the principal organ in the olfactory
system.
The shape of the nose is determined by
the nasal bones and the nasal cartilages,
including the nasal septum which separates
the nostrils and divides the nasal cavity into
two.

5. Introduction con’t...
On average the nose of a male is
larger than that of a female.
The nose and paranasal sinuses
are regarded as functional unit.
Many rhinological disorders are
transmitted from the nasal cavity
into paranasal sinuses system.
So it is of clinical importance to
know anatomical details of this
region.

6. 2. Embryology of the Nose
The nasal development is
intimately associated with the
development of palate and mid
face
Development of these structures
is a complex process involving
interaction of the nasal
placode, frontonasal
prominence and branchial
arch tissue.

7. Embryology of the Nose con’t…
At the end of the fourth week of
foetal development, the human
embryo is approximately 5mm in
length, mesenchymal cells of neural
crest origin start to aggregate to form
the facial prominences in the
midface.
And the early face consists of
primitive opening called;-
i. Stomodeum
ii. Frontonasal prominence
iii. Paired nasal placodes
iv. Maxillary and mandibular

8. Embryology of the Nose con’t…
The nasal placodes arise as
thickenings of embryonic ectoderm
(overlying the frontonasal process and
situated above the stomatodaeum).
The nasal placodes invaginate to
form nasal pits which will give rise to
medial and lateral process
The nasal pits now deepen to form the
nasal sacs which expand both
dorsally and caudally to form the
nasal cavity.
As the nasal sac invaginates, an
oronasal membrane forms and
transiently separate the nasal

9. Embryology of the Nose con’t…
The dorsal part of this sac is, at
first, separated from the
stomatodaeum by a thin membrane
called the bucconasal membrane.
The nasal sac now has a ventral
orifice that opens on the face -
anterior or external nares.
And a dorsal orifice that opens into
the stomatodaeum - primitive
posterior nasal aperture.

10. Embryology of the Nose con’t…
The frontonasal process become
narrow and enlargement of the nasal
cavities bring the the tissues together
to form the nasal septum.
 The lateral wall of the nose is
derived, on each side, from the lateral
nasal process.
The nasal concha appear as
elevations on the lateral wall of each
nasal cavity.

11. Embryology of the Nose con’t…
Further development of frontonasal
and maxillary prominences will
form.
Primary and Secondary palate
Superior, middle and inferior
conchae on the lateral nasal walls.
Below each conchae is where the
meatus lie.

13. 3. Growth Anatomy of the Nose
The nose consists of the;-
a. External nose, and
b. Nasal cavity.
Both are divided by a septum
into right and left halves.

14. a. External nose
It is a pyramidal projection in the
mid face. Presenting with:-
1. Tip (or apex), the lower free end.
2. Root or bridge
3. Dorsum, a round border between tip
and root where sides of the nose
meet.
4. Nostrils or nares, the two piriform
apertures at the broad lower end,
separated by the nasal septum.
5. Ala, the lower flared part on the side
of nose.

15. 3. Growth Anatomy of the Nose
The upper one-third is a bony
framework formed by:-
1. Two nasal bones
2. Frontal processes of the maxillae
bone
3. Nasal part of the frontal bone.
The lower two-third is a
cartilaginous framework
1. Two lateral cartilages.
2. A single median septal cartilage.
3. Two major alar cartilages.
4. Lesser ala cartilages

16. i. Blood Supply of the External
Nose
The skin of the external nose is supplied
by branches of :-
1. Ophthalmic artery (ICA).
- Dorsal nasal branch (nasal dorsum and
nasal side
wall).
- External nasal branch of the anterior
ethmoid
artery (nasal dorsum and nasal side wall).
2. Maxillary artery (ECA)
- Infra-orbital artery branch Supplies
the dorsum
and nasal side wall.

17. Blood Supply con’t…
3. Facial artery (ECA)
- Angular artery and its lateral
nasal branch supply the nasal
side wall and ala.
- The superior labial artery
i. Columellar branch (
supplies the nasal sill and
columella)
ii. Septal branch (supplies
the anterior nasal septum).

18. Venous drainage
Corresponds to arterio-venous
units.
Fronto-median area drains
into facial vein (Originates as
the angular vein which forms as
the confluence of the
supratrochlear and supraorbital
veins)
Orbito-palpabral area –
ophthalmic vein (cavernous
sinus communication)

19. The upper lip and external nose are
considered the DANGER
AREA/TRIANGE OF THE FACE
infections in this region may be
transmitted in a retrograde fashion
intracranially to the cavernous
(because the facial vein communicates
through a valveless venous system
with the cavernous sinus via the
ophthalmic vein).

20. Lymphatic drainage
The lymphatic drainage of the
external nose is directed towards the
submandibular nodes,
submental nodes and facial
nodes.
Drainage of the external nose is
often bilateral and drainage to
the parotid region may be
possible.

21. 1. External Nasal
2. Branch Of
Anterior Ethmoidal
Nerve
1. Infratrochlear
2. Branch of
Nasociliary
nerve

22. b. Nasal cavity.
Extends from the external
(anterior) nares to the posterior
nares (choanae).
Divided into right & left halves
by the nasal septum.
Each half is divided into:
i. Floor
ii. Roof
iii. Medial wall (septum)
iv. Lateral wall

23. Nasal cavity con’t...
The Lateral Nasal cavity has three
segments, namely:-
1. Vestibule
- It is lined with keratinized stratified
squamous epithelium.
- Has sweat and sebaceous glands, hair
follicles and the hair (vibrissae).
2. Respiratory region.
- It is lined with pseudostratified
columnar ciliated epithelium with goblet
cells.
- Lamina propria contains seromucous

24. Nasal cavity con’t...
3. Olfactory area
-It is lined with olfactory mucosa which is
very thick pseudostratified columnar
epithelium with olfactory cells that
contains receptors for the sense of smell.
- Bowman’s gland/ olfactory gland- in the
lamina propria of olfactory membrane,
contains fibroblasts, blood vessels,
bundles of fine axon from olfactory
neurons.

25. i. Floor of Nasal Cavity
The anterior three quarters are
comprised of the palatine
process of the maxilla.
The posterior one quarter by
the horizontal process of the
palatine bone.

26. ii. Roof of Nasal Cavity
It is formed by:-
a. The nasal and frontal bones-
anteriorly beneath the bridge of the
nose.
b. The cribriform plate of the
ethmoid
bone-in the middle part, located
beneath the anterior cranial fossa.
c. The downward sloping body of
sphenoid bone-posteriorly.

27. iii. Medial Wall of Nasal Cavity
It is called the Nasal Septum
It divides the nasal cavity into right
and left halves
It has osseous and cartilaginous
parts.
Nasal septum consists of:-
a. The perpendicular plate of the
ethmoid
bone (superior),
b. Vomer (inferior)
c. Septal cartilage (anterior)
Perpendicul
ar Plate
(ethmoid)
Septal
Cartilag
e Vome
r

28. iv. Lateral Walls of Nasal Cavity.
Marked by 3 projections:
1. Superior
concha/turbinate
2. Middle
concha/turbinate
3. Inferior
concha/turbinate
- The nasal turbinates
continuously dilate and
constrict every 0.5–3 hours in
a normal physiological
phenomenon known as the
‘nasal cycle’.

30. Lateral wall con’t…
1. Inferior meatus: Nasolacrimal duct
(nasolacrimal duct opening is called
Hasner’s valve.)
2. Middle meatus:
a. Maxillary sinus
b. Frontal sinus
c. Anterior ethmoid sinuses
3. Superior meatus: Posterior ethmoid
sinuses
4. Sphenoethmoidal recess: Sphenoid
sinus

31. Ostiomeatal unit/Ostiomeatal complex
(OMC)
The area on the lateral nasal wall
(middle meatus) that receives
drainage from;-
- The anterior and medial ethmoid
cells
- Frontal sinus
- Maxillary sinus.
It is an anatomically constricted area
that is prone to blockage, especially in
the presence of structural anomalies,
mucosal swelling or tumors.
In addition, ostia themselves are
small.
An impairment in the ventilation of

32. Blood Supply to the Nasal Cavity
(Lateral)
1. External Carotid Artery
-Sphenopalatine artery
(maxillary artery)
-Greater palatine artery
(maxillary artery)
-Posterior nasal artery
-Superior Labial artery (facial
artery)
2. Internal Carotid Artery
-Anterior Ethmoid artery
(opthalmic artery)
-Posterior Ethmoid artery
(opthalmic artery)

33. Blood Supply con’t… (Medial)
From branches of the maxillary
artery, one of the terminal
branches of the External
carotid artery.
The most important branch is
the sphenopalatine artery
which anastomoses with the
septal branch of the superior
labial branch of the facial artery
in the region of the vestibule.
The submucous venous plexus
is drained by veins that
accompany the arteries.

34. Blood Supply con’t…
a. Kesselbach’s Plexus/Little’s
Area;
-Anterior Ethmoid (Opth)
-Superior Labial A (Facial)
-Sphenopalatine A (MAX)
-Greater Palatine (MAX)
b. Woodruff’s Plexus:
-Sphenopalatine A (MAX) &
Pharyngeal A (MAX)

35. Nerve Supply of the Nasal Cavity
The olfactory nerves from the olfactory mucous membrane
ascend through the cribriform plate of the ethmoid bone to the
olfactory bulbs .
 Olfactory nerves carry meningeal sheaths of dura, arachnoid
and pia mater and because of this injury to these nerves can
result in CSF rhinorrhea and meningitis.
The nerves of ordinary sensation are branches of the
ophthalmic division (V1) and the maxillary division (V2) of
the trigeminal nerve.

36. Nerve Supply con’t…
CN I – Olfactory Nerves (SVA)
Anterior ethmoidal
branch of V1
Posterior nasal
branches of V2
Cut nasopalatine
branch of V2 to
septum

37. Lymph Drainage of the Nasal Cavity
The lymph vessels draining the
vestibule end in the
submandibular nodes.
The remainder of the nasal
cavity is drained by vessels that
pass to the upper deep cervical
nodes.

38. 4. Functions of the Nose.
1. Air conditioning: warming, cleaning and humidifying
the inhaled air
2. Add resonance to the voice
3. Vocal sounds are also produced in the nasal cavity
thus aiding in vocalization
4. Involved in the special sense of smell
5. Cosmetic role in facial appearance

39. 5. Anatomic variations.
1. Concha Bullosa
2. Uncinate Process
3. Deviated Nasal
Septum

40. 6. Clinical Application
a. Congenital
1. Choano atresia
2. Dorsal nasal fistula
3. Kallmans syndrome (Congenital anosmia)
4. Cleft lip and palate
5. Arhinia (absence of the nose)
6. Frontonasal dysplasia (primary defect in the nasofrontal process that
prevents appropriate migration to the midline)
7. Nasal dermoid sinuses and cysts
8. Nasal encephaloceles (herniations of brain, meninges)

41. Dorsal nasal fistula

42. Cleft lift and Palate

43. Arhinia
(A) Two-year-old child with arhinia and left-sided iris coloboma.
(B) Ten-year-old child with arhinia and left-sided microphthalmia and
bilateral nasolacrimal duct stenosis.
(C) Newborn with arhinia and normal eye anatomy and vision.
(D) Sixteen-year-old with arhinia and right-sided microphthalmia.
(E) One-year-old child with arhinia, bilateral colobomatous microphthalmia,
cataracts, and nasolacrimal duct atresia.

44. b. Acquired
1. Trauma to the Nose
2. Infection of the Nasal
Cavity
3. Foreign Bodies in the
Nose
4. Nose Bleeding
(Epistaxis) Epistaxis:
(Little’s area)

45. 2. PARANASAL SINUSES

46. 1. Introduction.
The paranasal sinuses are paired and symmetrical,
air-filled cavities situated around the nasal cavity.
Paranasal sinuses are found in three bones of
the neurocranium (braincase), the frontal
bone, ethmoid bone, and sphenoid bone.
The maxilla is the only facial bone
(viscerocranium) that contains its own sinuses.
The four pairs of sinuses are named by their
corresponding bones and include:
a. The maxillary sinuses
b. The frontal sinuses
c. The sphenoidal sinuses
d. The ethmoidal cells (sinuses)

47. Introduction con’t...
The mucosa of the paranasal sinuses contains pseudostratified ciliated
columnar to cuboidal cell epithelium, is thin, and contains a few glands.
The basement membrane is thin.
 Cilia, somewhat more abundant near the sinus ostia, propel the overlying
blanket of mucus through the ostium, where it joins that in the nose.
Clinically divided into 2 groups;-
1. Anterior group:
- It includes those sinuses, which drain into the middle meatus, viz. frontal,
anterior and middle ethmoidal, and maxillary sinuses.
2. Posterior group:
- It includes those sinuses, which do not drain into the middle meatus, viz.
posterior ethmoidal and sphenoidal air sinuses

49. 2. Embryology of Paranasal sinuses
Paranasal sinuses' development is heralded by the
appearance of a series of folds on the lateral nasal wall at
approximately the eighth week of gestation, known as
the ethmoturbinals.
Six to seven folds emerge initially, but eventually, only
three to four persist through regression and fusion.
a. First ethmoturbinal: they are rudimentary and
incomplete in humans. The ascending portion forms
the agger nasi descending portion forms the uncinate
process.
b. Second ethmoturbinal: it forms the middle
turbinate.
c. Third ethmoturbinal: it forms the superior
turbinate.
d. Fourth and fifth ethmoturbinals: they fuse to form
the supreme turbinate.

50. Embryology con’t…
As development progresses, furrows form
between these ethmoturbinals, which
establishes rudimentary meati and
recesses.
The frontal sinus originates from the
anterior pneumatization of the frontal
recess into the frontal bone.
The frontal sinus does not appear until
the age of 5 to 6 years old.
The sphenoid sinus develops during the
third month of gestation.
During this time, the nasal mucosa
invaginates into the posterior portion of
the cartilaginous nasal capsule to form a
pouch-like cavity.
The wall surrounding this cartilage is
ossified in the later months of fetal

51. Embryology con’t…
Then, during the second and third years of life, the cartilage is
resorbed, and the cavity becomes attached to the body of the
sphenoid.
By the sixth or seventh year of life, pneumatization of the
sphenoid sinus progresses.
By twelve years of age, the pneumatization is complete with
pneumatization of the anterior clinoids and pterygoid process.
The maxillary sinus starts developing during the 10th week of
intrauterine life.

52. Embryology con’t…
 The ethmoid infundibulum invaginations towards the
mesenchyme fuse during the 11th week of development, forming
one oval cavity with smooth walls – the primordium of the
maxillary sinus.
The sinus ossification starts during the 16th week.
 The maxillary sinus shows a biphasic growth pattern at 3 and 7 to
18 years of age.
The ethmoid sinuses are comprised of three to four air cells at
birth. By the time an individual reaches adulthood, they consist of

54. 3. Growth Anatomy of Paranasal sinuses
a. The maxillary sinuses
Pyramidal in shape
Paired & symmetric
 Located within the body of the
maxilla behind the skin of the
cheek.
The maxillary sinus opens into the
middle meatus of the nose

55. Maxillary Sinus con’t...
Boundaries
a. Anterior wall: The anterior facial surface of
maxilla (canine fossa) is related to cheek.
b. Posterior wall: It is in relation with the
infratemporal and pterygopalatine fossa.
c. Medial wall: It is thin and membranous at
places and faces middle and inferior meatuses
d. Floor: It is formed by alveolar process of the
maxilla. The roots of all the molars, second
premolar and sometimes first premolar
(depending on the extent of pneumatization and
age of the person), are situated in the floor of
maxillary sinuses..
e. Roof: The roof of the maxillary sinus is the
floor of the orbit and is traversed by infraorbital

56. b. The frontal sinuses
Rarely symmetrical
Contained within the frontal bone .
Separated from each other by a bony
septum.
Each sinus is roughly triangular
Extending upward above the medial
end of the eyebrow and backward
into the medial part of the roof of
the orbit.
Opens into the middle meatus

57. Frontal sinuses con’t…
Boundaries
a. Anterior wall of the sinus is related
to the forehead skin.
b. Floor is in relation with orbit.
c. Posterior wall relations are
meninges and frontal lobe of brain.
Ostium of frontal sinus is situated
in its floor and opens into the
frontal recess, which depending
upon the attachment of uncinate
process opens either in the
infundibulum or medial to the
uncinate process into the middle
meatus.

58. c. The sphenoidal sinuses
The sphenoid sinuses are paired spaces
formed within the body of the sphenoid
bone, communicating with the roof of the
nasal cavity via the sphenoethmoidal
recess in its anterior wall.
The two hemisinuses are separated by a
septum which may or may not be in the
midline.
It usually lies anteroinferior to the sella.
A large sinus can show a number of ridges
and depressions related to closely adjacent
structures. These can include
the pituitary gland, optic nerve,
and internal carotid artery.

59. Sphenoidal sinuses con’t…
Relations
a. Superiorly: cavernous
sinus, sella
turcica, and its contents
b. Inferiorly: nasal cavities
c. Anteriorly: nasal cavities,
posterior ethmoid air cells
d. Posteriorly: contents of
the middle
cranial fossa
e. Laterally: cavernous sinus,
cranial cavity

60. Sphenoid sinus pneumatization

61. d. The ethmoidal cells (sinuses)
They are contained within the ethmoid
bone, between the nose and the orbit.
They are anterior, middle, and posterior
Anterior & middle
- Drains into middle nasal meatus
Posterior
- Drain into superior nasal meatus
Separated from the orbit by a thin plate
of bone (Lamina papyracea) so that
infection can readily spread from the
sinuses into the orbit

62. Ethmoidal sinuses con’t…
Boundaries
a. Roof: It is closed by the frontal bone,
which forms the floor of anterior cranial
fossa.
b. Lateral wall: Lamina papyracea
separates it laterally from the orbit.
Lamina papyracea is paper thin and can
be easily damaged during intranasal
surgery and destroyed by ethmoidal
infections.
Optic nerve, which is at risk during
posterior ethmoid surgery, is in close
relationship with posterior group of
ethmoidal air cells.

63. Blood and nerve supply of the Paranasal
sinuses

64. Summary of development, vascular supply and innervation of the
paranasal sinuses.

65. 4. Functions of Paranasal sinuses
1. Resonators of the voice
2. Reduce the skull weight
3. Help warm and moistening inhaled air
4. Act as shock absorber in trauma

66. 5. Anatomic variations.
The significance of anatomic variations are determined by their
relationship between the ostiomeatal channels and nasal air
passages.
Knowledge of these anatomical variations is of clinical
importance in every patient.
Help to avoid damage to the surrounding vital structure during
surgery

67. Anatomic variations con’t...
Deviated Nasal Septum
Concha bullosa (Enlarged, pneumatized middle turbinate)
Intralamellar cell (Air cell witihin vertical portion of middle turbinate)
Paradoxical middle concha (Convexity of turbinate directed towards
lateral nasal wall)
Haller cells (Infraorbital ethmoid air cells)
Agger Nasi cells (Extension of anterior ethmoid air cells into lacrimal
bone)
Uncinate process bulla
Deviation of uncinate process
 Fronto-ethmoid/kunh cells/bulla frontalis (Are the anterior ethmoid
cells which invade the frontal bone, bulging its floor)
Accessory Maxillary ostia

68. 6. References
1. Ogle OE, Weinstock RJ, Friedman E. Surgical anatomy of the nasal
cavity and paranasal sinuses. Oral Maxillofac Surg Clin North Am.
2. Iwanaga J, Wilson C, Lachkar S, Tomaszewski KA, Walocha JA,
Tubbs RS. Clinical anatomy of the maxillary sinus: application to
sinus floor augmentation.
3. Ballenger’s ORL, Head and Neck Surgery.
4. Gray’s Anatomy for students, 2004.
5. Atlas of human Anatomy,Frank H. Netter