Anatomy and physiology of nose and paranasal sinuses

Anatomy and physiology of nose and paranasal sinuses

1. ANATOMY &
PHYSIOLOGY
OF NOSE AND
PARANASAL
SINUSES
BRIG ANWAR UL HAQ
00923018513303
PAKISTAN

2. ANATOMY OF NOSE
EXTERNAL NOSE
•Osteocartilagenous framework:
Upper 1/3
rd
- Bony
Lower 2/3
rd
– Cartilagenous
•Bony framework
a)Nasal bones
b)Nasal processes of frontal bone
c)Frontal processes of maxilla

3. APPLIED ANATOMY
•Dangerous area of face- The lower part of
external nose and the upper lip. Infection
may spread to cavernous sinus through
inferior ophthalmic vein via anterior facial
vein which have no valves
•Dangerous area of nose- olfactory area
Infection may spread into meninges along
the pia and arachnoid sheath of olfactory
nerves. This area is also connected to
superior sagittal sinus and cavernous
sinus by venous channels

4. ANATOMY OF NOSE
EXTERNAL NOSE
•Cartilagenous framework
a)Upper lateral cartilages
b)Lower lateral cartilages (alar cartilages)
c)Lesser cartilages (sesamoid cartilages)
d)Septal cartilage
Clinical significance: limen nasi (nasal
valve) is the narrowest area in the upper
airway

5. ANATOMY OF NOSE
EXTERNAL NOSE
•Nasal valve: Formed by lower edge of
upper lateral cartilages, the anterior end of
inferior turbinate and adjacent nasal
septum.
•Cottle’s test: used in nasal obstruction
due to abnormality of nasal valve.

8. ANATOMY OF NOSE
EXTERNAL NOSE
•Nasal musculature:
a)Procerus
b)Nasalis (transverse and alar part)
c)Levator labi superioris alaque nasi
d)Anterior and posterior dialator naris
e)Depressor septi
Nasal skin: skin over nasal bone and upper
lateral cartilage is thin and freely mobile
while that on alar cartilages is thick and
adherent and contains sebaceous glands

9. ANATOMY OF NOSE
EXTERNAL NOSE
•Blood supply:
–facial and ophthalmic arteries and
veins
•Lymphatic drainage:
–preauricular
–submandibular lymph nodes

10. ANATOMY OF NOSE
INTERNAL NOSE
•It is divided into right and left nasal cavities
by nasal septum.
Each nasal cavity consists of
a)Skin lined portion-vestibule (contains
sebaceous glands, hair follicles, vibrissae)
b)Mucosa lined portion-nasal cavity
proper

11. ANATOMY OF NOSE
INTERNAL NOSE
•Nasal cavity proper: bounded by lateral
wall, medial wall, roof and a floor.
•Floor: Formed by
–Palatine process of maxilla (anterior 3/4
th
)
–Horizontal process of palatine bone (posterior
1/4
th
)

12. ANATOMY OF NOSE
INTERNAL NOSE
•Roof: formed by
–Anterior sloping part by nasal bones
–Posterior sloping part by body of sphenoid
–Middle horizontal part by cribriform plate of
ethmoid through which olfactory nerves enter
the nasal cavity

13. ANATOMY OF NOSE
INTERNAL NOSE
•Medial wall of nasal cavity (nasal septum)

14. ANATOMY OF NOSE
INTERNAL NOSE (Septum)
•Nasal septum consists of three parts
a)Columellar septum
b)Membranous septum (lies between
columella and caudal border of septal
cartilage)
c)Septum proper: consists of
osteocartilagenous framework covered with
nasal mucous membrane

15. ANATOMY OF NOSE
INTERNAL NOSE(Septum)
•Septum proper: principal constituents
a)Perpendicular plate of ethmoid postero-
superiorly
b)Vomer infero-posteriorly
c)Septal cartilage (quadrilateral cartilage)
•These articulate with following bones to
complete the septum
a)Superiorly-frontal bone, nasal bone,
rostrum of sphenoid.
b)Inferiorly anterior nasal spine of maxilla,
nasal crest of maxilla and palatine bones

17. BLOOD SUPPLY-NASAL
SEPTUM
•Little’s area: Situated in the antero-inferior
part of nasal septum just above the
vestibule. Four arteries-
–anterior ethmoidal
–septal branch of superior labial
–septal branch of sphenopalatine
–greater palatine
•anastamose here to form kiesselbach’s
plexus.

18. BLOOD SUPPLY-NASAL
SEPTUM

19. NERVE SUPPLY-NASAL
SEPTUM

20. ANATOMY-LATERAL WALL OF
NASAL CAVITY

21. ANATOMY-LATERAL
WALL OF NASAL CAVITY
a)Ascending process of maxilla
b)Nasal bone
c)Ethmoid
d)Medial part of maxilla
e)Inferior turbinate
f)Perpendicular plate of palatine bone
g)Medial pterygoid plate

22. ANATOMY-LATERAL WALL OF
NASAL CAVITY
•Three bony projections
–turbinates or conchae-
•Superior (part of ethmoid)
•Middle (part of ethmoid)
•Inferior (separate bone)
•Sometimes 4th turbinate concha
suprema
•Bellow and lateral to each turbinate
–corresponding meatus

23. ANATOMY-LATERAL WALL OF
NASAL CAVITY
•Inferior meatus-
–nasolacrimal duct opens in its anterior part.
•Middle meatus-
–consists of bulla ethmoidalis, hiatus
semilunaris, infundibulum. Frontal, maxillary
and anterior ethmoidal sinuses open into
middle meatus.

24. ANATOMY-LATERAL WALL OF
NASAL CAVITY
•Superior meatus-
–Posterior ethmoidal sinuses
•Sphenoethmoidal recess-
–Sriangular fossa above the superior meatus.
–Sphenoidal sinus

25. ANATOMY-LATERAL
WALL OF NASAL CAVITY

26. BLOOD SUPPLY-
LATERAL WALL OF NASAL CAVITY

27. NERVE SUPPLY-
LATERAL WALL OF NASAL CAVITY

28. AUTONOMIC NERVE SUPPLY-
NASAL CAVITY
•Sympathetic supply-
–Superior cervical sympathetic ganglion
–Internal carotid plexus
–vidian nerve
–sphenopalatine ganglion.

29. AUTONOMIC NERVE SUPPLY-
NASAL CAVITY
•Parasympathetic supply-
–facial nerve
–greater superficial petrosal nerve
–vidian nerve
–sphenopalatine ganglion.
–Nasal branches from sphenopalatine ganglion

30. SENSORY NERVE SUPPLY-
NASAL CAVITY
•Common sensation
–Trigeminal nerve
•ophthalmic
•maxillary divisions.
•Special sensory (smell)
–Olfactory nerves.

31. LYMPHATIC DRIANAGE-
NASAL CAVITY
•Upper deep cervical nodes drain the nasal
cavity directly or via the retropharyngeal
nodes.

32. PARANASAL SINUSES-
ANATOMY
•These are air filled spaces
•Certain bones of skull
•Direct communication with nasal cavity
through their ostia
•Four on each side divided as

33. PARANASAL SINUSES-
ANATOMY
a)Anterior group-
a)Maxillary
b)Frontal
c)Anterior ethmoidal
b)Posterior group-
a)Posterior ethmoid
b)Sphenoid

34. Development of Sinuses
•Outpouching from mucus membrane of
nose
•at birth:-Maxillary and ethmoidal present
•At 6-7 yrs:- frontals and sphenoids
•At 17-18 :- all full developed

35. Drainage

36. Objectives
•To know anatomical location
•Their connections &
significance
•Development
•Neurovascular supply
•Applied anatomy

37. Introduction
•Air containing
cavities.
•Each sinus are
named after the
bone it resides in.
•4 pairs :-
•frontal
•maxillary,
ethmoidal,
sphenoidal

38. Lateral view

39. Anterior view

40. Maxillary sinuses
•Largest PNS
•Pyramidal shape
•Base pointing to
lateral wall of nose
•Apex laterally in
the zygomatic
process
•Capacity 15 ml

41. Relations
•Anterior:-
–Facial surface of
maxilla
•Posterior:
–Infratemporal and
pterygopalatine fossa
•Medial:-
–Middle and inferor
meatus
•Floor:-
–Alveolar and palatine
processes of maxilla
•Roof:-
–Floor of orbit

42. BLOOD SUPPLY MAX SINUS
•Blood supply :
–Facial
–infra orbital
–greater palatine arteries.
•Lymphatic drainage :
–Submandibular nodes.
•Nerve supply :
–Infra orbital, anterior
–middle and post superior alveolar nerves

44. Frontal sinus
•Resides in frontal
bone
•2
nd
largest
•Asymmetrical
•Usually paired-
sometimes one,
three or none!

45. Relations-Frontal Sinus
•Anterior:-
–Skin over the forehead
•Inferior:-
–Orbit & its contents
•Posterior:-
–Meningeal and frontal lobe
of brain

46. Neurovascular supply
• Blood supply –
–Supra orbital artery
Anterior ethmoidal arteries.
•Venous return –
– Anastomotic veins in supra orbital notch,
connecting supra orbital and supra ophthalmic
veins.
• Lymphatic drainage –
–Submandibular nodes.
•Nerve supply –
–Supra orbital nerve traversing the floor of the sinus.

47. Ethmoidal sinuses
•Resides in ethmoid
bone
•3 groups:-
–anterior
–Posterior
–sphenoethmoidal
recess
•Number varies from
3-18
•Present from birth

48. Relation(Ethmoids)
•Roof:-
–anterior cranial fossa
•Lateral:-
–orbit (separated by
lamina papyracea)
•Optic nerve lies close
to posterior ethmoidal
cells

49. Neurovascular
supply(Ethmoids)
•Blood supply :
–Sphenopalatine artery
Anterior and posterior ethmoidal
artery.
•Lymphatic drainage :
–Submandibular nodes
Retropharyngeal nodes.
•Nerves :
–Anterior and posterior ethmoidal
nerves.
Orbital branches of pterygopalatine
ganglion..

50. OSTEOMEATAL COMPLEX
•The middle meatus
–Space below and lateral to the middle turbinate,
–Functionally referred as osteomeatal complex
–Drainage pathways
•Anterior ethmoids
•Maxillary
•Frontal sinuses.
•The middle meatus
–Pathophysiology of chronic rhinosinusitis.

51. OSTEOMEATAL COMPLEX-
RELATED STRUCTURES
•Bulla ethmoidalis- The ethmoid bulla is
one of the most constant and largest of
the anterior ethmoid air cells. It is located
within the middle meatus directly posterior
to the uncinate process and anterior to the
basal lamella of the middle turbinate.

52. OSTEOMEATAL COMPLEX-
RELATED STRUCTURES
•Hiatus semilunaris- Hiatus semilunaris is a
crescent shaped gap between the
posterior free margin of the uncinate
process and the anterior wall of the
ethmoid bulla, through this passage the
middle meatus communicates with the
ethmoid infundibulum .

53. OSTEOMEATAL COMPLEX-
RELATED STRUCTURES
•Ethmoidal infundibulum - Ethmoidal
infundibulum is the funnel-shaped
passage through which the secretions
from various anterior ethmoid cells, the
maxillary sinus, and, in some cases, the
frontal sinus are transported or channeled
into the middle meatus.

54. OSTEOMEATAL COMPLEX-
RELATED STRUCTURES
•Uncinate process- floor and medial wall of
infundibulum is formed by the uncinate
process of the ethmoid. This structure is
nearly sagittally oriented, nearly paralleling
the ethmoidal bulla. It is approximately 3
to 4 mm wide and 1.5 to 2 cm in length.

55. Sphenoid sinus
•Resides in body of
sphenoid
•Paired
•Asymmetrical
•Not present at birth

56. Relation(Sphenoid)
•Lies below to sella turcica
•Sphenoid effusion shows skull base fracture
•Related to
–optic tractchiasma
–internal carotid artery

57. Sphenoid Sinus
•Blood supply :
–Posterior ethmoidal artery.
•Lymphatic drainage
–Retropharyngeal nodes.
•Nerve supply :
–Posterior ethmoidal nerve.

58. Microscopic Anatomy
•Lined by mucus
membrane
•Ciliated columnar
epithelium
• Goblet cells secretes
mucus
•Cilia are more
marked near ostia.

60. 60

61. Introduction
•organ of smell
•Organ of respiration
•It warms, cleans and humidifies the
inspired air, cools and remove the
water from the expired air
•It also adds quality to speech
production
61

62. Introduction
•The ENT surgeon should
distinguish normal nasal function
from pathological symptoms to
prevent unnecessary surgery
•Although the nose is a paired
structure divided coronally into two
chambers, it act as a functional unit
62

63. Function Mechanism
Respiration
Heat exchange
Direction of blood flow
Latent heat of evaporation
Thermoregulation
Humidification
Anterior serous glands
Mixed serous and mucus glands
Capillary permaebility
Other body fluids; e.g. tears
Filtration Airflow pattern: laminar/turbulent
Nasal resistance
Anatomical, fixed
Neurovascular, variable
Nasal fluids and ciliary
fuction
Mucus, mucins
Protein including immunoglobulins
Ciliary structure and function
Nasal neurovascular
reflexes
Parasympathetic
Sympathetic
Sensory: axon reflexes
Sneezing
Central: pulmonary reflexes
Nasal cycle
Voice modificationNasal escape
63

64. Olfaction
Stimulus
Threshold and suprathreshold
Adaptation, discrimination and classification
Pathways Neurones in contact with the external environment
Two neurone
peripheral pathway
Higher centres
Perceived smell
Trigeminal input Pain
Olfaction and
behaviour
Pheromones
64

65. Respiration
•Air conditioning unit
•Humidification
•Heat transfer
–Temperature regulation
•Filtration
–Inspired gases contain pollutants,
domestic dust particles and pollen,
industrial products, bacteria, viruses
and tobacco smoke
•Bypasses during exercise
•Temperature regulation
65

66. I. Heat Exchange
•Inspired air
–Vary from -50 to 50
o
c
Conduction, convection and radiation
•Conduction occurs without flow when heat
is transferred by increased molecular
movement
•A temperature gradient leads to convection
of currents  affect airflow in the nose 
turbulence
•Flow results in forced convection
66

67. II. Humidification
•Vaporization cools the surface
•10 percent of the body heat is lost
Inspiration
•Saturation follows the temperature rise
rapidly
67

68. II. Humidification
•Energy required for:
–raising the temperature of inspired air (1/5)
–The amount of energy is dependent on ambient
temperature and relative humidity of an inspired
air
–Heat of evaporation (4/5)
•10% of body heat loss occurs through the
nose in humans
•Air in post nasal space is approximately 31
o
C
and is 95% saturated
2
68

69. Expiration
•expired air at the back of the nose
–slightly below body core temperature
–saturated
•Some water condenses into the
mucosa as the temperature drops
along the nose
•The temperature in the anterior
nose at the end of the expiration is
32
o
C and approximately 30
o
C at the
end of inspiration
•Approximately 1/3
rd
of the water
required to humidify the inspired air
is recovered in this way
•People who breathe in through the
nose and out through the mouth will
dry the mucosa
69

70. Water production
•Water comes from the serous gland,
which are extensive throughout the
nose
•During nasal cycle, secretions are
lower on the more obstructed side
•Additional water comes from the
expired air, the nasolacrimal duct
and the oral cavity
•Humidification is reduced by
atropine probably acting on the
gland rather than the vasculature
3
70

71. III. Airflow
•The airflow and the sensation of it are very
different
•Cold receptors sense airflow
•Most of the work of heat and mass
transport has been performed on simple
structures with constant cross sections.
2
•The flow is turbulent, but is considered
laminar at rest
•The equations below describe flow, two for
laminar and one for the transition to
turbulent flow
Airflow : VA = constant
Bernoulli’s equation : P + ½ ρV
2
= constant
Reynolds number : Re =
ρ = density (g m
-1
); V = velocity (m sec
-1
); A = cross-sectional area (m
2
);
P = pressure (N m
-2
); d = diameter (m); =
ƞ
viscosity (g sec
-1
m
-1
)
71
dVρ
ƞ

72. •Gases flow faster through the choana
4
•The characteristic of air flow were similar in different
noses regardless of variety of nasal shape
•The cross-sectional flow is maximal at the centre and is
zero at the edge
•Bernoulli equation is not strictly applicable since the
energy overcoming the viscosity results in an irreversible
drop in pressure
•The nose has variable cross section – the pressure and
velocity will alter continuously within the system
•Because of the flow is turbulent in an irregular tube, the
resistance is inversely proportional to the square of the
flow rate
5
72

73. Inspiration
•Airflow is directed upwards and
backwards from the nasal valve
initially, mainly over the anterior part
of the inferior turbinate
•It then splits into two, below and
over the middle turbinate, rejoining
into posterior choana
•Air reaches the other parts of the
nose to a lesser degree
•The velocity at the anterior valve is
12 - 18 m per sec during quiet
respiration
73

74. 74

75. Expiration
•Expiration lasts longer than inspiration
and is more turbulent
•Extrapulmonary airflow is turbulent
because of the direction changes, the
calibre varies markedly and walls are
not smooth. The surface area is
enlarged by the turbinates and the
microanatomy of the epithelium
75

76. Nasal resistance
•Differs between races
•The nose accounts for up to half of the total
airway resistance
•Produced by two resistors
–fixed: bone, cartilage and muscle
–variable: mucosa
•High in infants (obligatory nose breathers)
•Adult breath preferentially through the nose at
rest even though there is a significant
resistance
76

77. The anterior nasal valve
•Narrowest part of the nose and less well defined
physilogically then anatomically
•Greatest resistor – produces the most turbulent
airflow
•Formed by the
–lower edge of the upper lateral cartilages
–anterior end of inferior turbinate
–adjacent nasal septum
–surrounding soft tissues
•EMG –
–contraction of the dilator naris
–increases during exercise
•Alar collapse occurs after denervation
77

78. Nasal cycle
•alternate nasal blockage between passages
•The changes are produced by vascular activity
particularly the volume of blood on the venous
sinusoids (capasitance vessels)
•Cyclical changes - 4 to 12 hours
•Can be demonstrated in over 80% of adults
•Difficult to demonstrate in children
•Nasal secretions are also cyclical with an
increase in secretions in the side with the
greatest airflow
3
78

79. Factors modify the nasal cycle
•allergy
•Infection
•Exercise
•Hormones
•Pregnancy
•Fear
•Emotions
•sexual activity
•Vagal overactivity
•Puberty 79
•Sympathomymetic
•Parasympathetic

80. IV. Protection of Lower Airway:
Mechanical and Chemical
•Removing particles - 30 μm,
–pollens from the inspired air
•Dust deposited in the nose
•Inspired air travels through 180
o
and velocity drops
markedly just after the nasal valve
•Turbulence increases deposition of particles
•Particles in motion - carry on in the same direction
•Resistance to change in velocity is greater in irregular
particles because of larger surface area and the
number of facets
•Vibrissae will only stop the largest particles
80

81. Nasal secretions
•Composed of :–
–Mucus
–Water
–Glycoprotein – goblet cells
–Water and ions –
–Submucosal glands
–Serous glands
•The anterior part of the nose
•Sinuses has fewer goblet cells and mixed
glands
81

82. 82

83. Proteins in nasal secretion
1.Lactoferrin
–Serous gland
–Bind divalent metal ions – like transferrin in
the circulation
–Lactoferrin and transferrin
•Prevent growth of certain bacteria,
•Staphylococcus and pseudomonas
1.Lysozymes
–Serous glands and tears
–Act only on non capsulated bacteria
83

84. 3.Antiproteases
–Produced by leukocytes
–Increase with infection
3.Complement
–C3 – produced by liver and locally by
macrophages
–Functions: lysis of microorganism,
enhancing neutrophil function
(leukotaxis)
3.Lipids
4.Ions and Water
84

85. Cilia
Ultrastructure
•Found on the surface of cells in the respiratory
tract
•Function: to propel mucus backwards
•All cilia have the same ultrastructure
•Nasal cilia - relatively short at 5 μm,
•Nasal cilia - with up to 200 per cell
•9 paired outer microtubules surround a single
inner pair of microtubules
85

86. 86

87. FACTORS AFFECTING
CILIARY ACTION
•Drying stops the cilia
•Temperature below 10
o
C and above 45
o
C
•Solutions above 5 % and below 0.2%
•pH below 6.4 and above 8.5
•Upper respiratory tract infection – damage
the epithelium
•Ageing
87

88. FACTORS AFFECTING
CILIARY ACTION
DRUGS
•Acetylcholine - increases the rate
•Adrenaline - reduces the rate
•Propanolol – reduces the rate
•Cocaine hydrochloride (>10%) –
causes immediate paralysis
•Corticosteroids – reduces the rate
88

89. V. Protection of Lower Airway:
Immunological
•IgA
•IgE
•IgM
•IgG
•Certain bacterial allergens are neutralized
•The T and some B cells interact with microphages,
•Dendritic cells are important in the allergic response
•cytokines
•Leukotrines
89

90. VI. Vocal Resonance
•Nose form resonating chamber for certain
consonants in speech
•Phonating nasal consonants (M/N/NG) –
•Many nasal condition affect the quality of
voice by blocking the passage of air
•Rhinolalia clausa – too little air escapes
from the nose
•Rhinolalia aperta – too much air escapes
90

91. VII. Olfaction
•Olfactory compound need high water and
lipid solubility
•The solute in the mucus is presented to the
sensory mucosa
Olfactory area
•Area: 200-400mm
2
•Receptor cells
Stimulus
React with lipid bilayer of the receptor cells at specific sites
cells depolarization
91

92. Adaptation
•Olfactoy responses show marked
adaptation and thresholds increase
with exposure
•Adaptation
–peripheral
–central phenomenon
•Cross adaptations
92

93. factors affecting threshold:
•Changes in nasal mucus and its ph
•Age – decreases the threshold
•Hormones (sex hormones) – increases the
threshold

94. Olfactory pathways
•Olfactory region (high up in nasal cavity)
•Olfactory cells and cillia
•Central process - olfactory nerves
•Pass through the cribriform plate
•Olfactory bulb
•Olfactory tract
•Prepyriform cortex
•Amygdaloid nucleus where it reaches
consciousness
94

95. 95

96. Disorders of smell
•Anosmia: total loss of smell
•Hyposmia: partial loss
•Parosmia: perversion of smell –
–Interprets the odour incorrectly
–Seen in
•Recovery phase of post influenzal anosmia,
•Intracranial tumour
96

97. Conclusion
•An understanding of the physiology of the nose
is required to:
–Evaluate nasal symptoms
–Know its protective role in
• Health
•Disease
–Determine the role of investigations in the
assessment of airway function and mucociliary
clearence
–Understand the action of drugs - nasal mucosa
–Assess the smell and taste
97