The Structure and Function of the anatomy and physiology of the 5th cranial nerve - three pairs of nerve the tri geminus nerve also called the tregeminal nerve. It supplies three arteries on left and on right

1. A n a t o m y a n d
P h y s i o l o g y o f
N o s e a n d
P a r a n a s a l S i n u s e s
Tariq Faridi

2. E x t e r n a l N a s a l F r a m e w o r k

3. • N a s a l B o n e
• F r o n t a l P r o c e s s o f M a x i l l a
• U p p e r L a t e r a l N a s a l C a r t i l a g e
• L o w e r L a t e r a l N a s a l ( A l a r ) C a r t i l a g e
• S e p t a l C a r t i l a g e
• L e s s e r A l a r ( S e s a m o i d ) C a r t i l a g e s

4. I n t e r n a l N o s e
• O p e n i n g s : A n t e r i o r n a r e s a n d p o s t e r i o r
n a r e s ( C h o a n a )
• V e s t i b u l e o f n o s e : l i n e d b y s k i n a n d
c o n t a i n i n g h a i r f o l l i c l e s
• N a s a l c a v i t y p r o p e r : L a t e r a l W a l l , M e d i a l
W a l l ( S e p t u m ) , R o o f , F l o o r

5. 1 . S e p t a l c a r t i l a g e
2 . E t h m o i d p l a t e
3 . V o m e r
4 . P a l a t i n e c r e s t
5 . M a x i l l a r y c r e s t
6 . V o m e r o n a s a l
c a r t i l a g e
7 . M e d i a l a l a r c r u s
8 . U p p e r l a t e r a l

9. L a t e r a l N a s a l W a l l
• 3 - 4 b o n y c o n c h a e a r e c o v e r e d w i t h
m u c o s a t o f o r m t h e t u r b i n a t e s
• S p a c e b e l o w a n d l a t e r a l t o t u r b i n a t e i s
c a l l e d m e a t u s
• M i d d l e m e a t u s c o n t a i n s a r o u n d b u l l a
e t h m o i d a l i s s e p a r a t e d f r o m u n c i n a t e
p r o c e s s b y h i a t u s s e m i l u n a r i s t h a t l e a d s

10. M e a t a l D r a i n a g e
1 . I n f e r i o r m e a t u s : N a s o l a c r i m a l d u c t
2 . M i d d l e m e a t u s : F r o n t a l , a n t e r i o r
e t h m o i d , m a x i l l a r y
3 . S u p e r i o r m e a t u s : P o s t e r i o r e t h m o i d
4 . S p h e n o - e t h m o i d a l r e c e s s : S p h e n o i d

13. O s t i o - m e a t a l C o m p l e x
C o m p l e x m i c r o - a r c h i t e c t u r a l p a t h w a y i n
e t h m o i d l a b y r i n t h t h a t d r a i n s a n t e r i o r

14. • O M C C o n s i s t s o f
– F r o n t a l r e c e s s + e t h m o i d
i n f u n d i b u l u m + h i a t u s s e m i l u n a r i s
+ u n c i n a t e p r o c e s s + b u l l a
e t h m o i d a l i s + m i d d l e m e a t u s
• O . M . C . p a t h o l o g y l e a d s t o i n f e c t i o n

15. V a r i a n t s i n O . M . C .
Concha bullosa (pneumatized M.T.)
Paradoxically curved middle turbinate
Medially turned ( bent) uncinate process
Large bulla ethmoidalis
Haller’s cell ( orbital floor)
Agger nasi cell ( anterior to M.T.)
Mucosal pathology

16. C o n c h a B u l l o s a

17. P a r a d o x i c a l l y c u r v e d M . T .

18. L a r g e b u l l a e t h m o i d a l i s

19. B l o o d S u p p l y
1 . S p h e n o p a l a t i n e a r t e r y ( m a i n a r t e r y )
2 . G r e a t e r p a l a t i n e a r t e r y
3 . S u p e r i o r l a b i a l a r t e r y
4 . A n t e r i o r E t h m o i d a l a r t e r y
5 . P o s t e r i o r E t h m o i d a l a r t e r y
1 , 2 , 3 & 4 f o r m K i e s s e l b a c h ’ s p l e x u s
o v e r L i t t l e ’ s a r e a o n a n t e r i o r s e p t u m

23. V e n o u s D r a i n a g e
• E t h m o i d a l v e i n s : → o p h t h a l m i c v e i n s →
c a v e r n o u s s i n u s
• S p h e n o p a l a t i n e v e i n : → p t e r y g o i d p l e x u s
→ m a x i l l a r y v e i n
• W o o d r u f f ’ s v e n o u s p l e x u s : p r e s e n t o n
l a t e r a l w a l l n e a r t h e p o s t e r i o r e n d o f
m i d d l e t u r b i n a t e
• R e t r o - c o l u m e l l a r v e i n : b e h i n d t h e

24. S e n s o r y N e r v e S u p p l y
• L o n g & s h o r t N a s o p a l a t i n e n e r v e s
• G r e a t e r p a l a t i n e n e r v e
• I n f r a - o r b i t a l n e r v e b r a n c h e s
• A n t e r i o r e t h m o i d a l n e r v e
• O l f a c t o r y n e r v e

27. A u t o n o m i c N e r v e S u p p l y
• D e e p p e t r o s a l n e r v e ( s y m p a t h e t i c ) +
g r e a t e r s u p e r f i c i a l p e t r o s a l n e r v e ( p a r a -
s y m p a t h e t i c ) → V i d i a n n e r v e → p t e r y g o
p a l a t i n e g a n g l i o n → n a s a l g l a n d s
• S y m p a t h e t i c s t i m u l a t i o n →
v a s o c o n s t r i c t i o n + ↓ e d n a s a l s e c r e t i o n s
• P a r a - s y m p a t h e t i c s t i m u l a t i o n →
v a s o d i l a t a t i o n + ↑ e d n a s a l s e c r e t i o n s

28. L i n i n g E p i t h e l i u m
• S k i n : o n t h e n a s a l v e s t i b u l e
• O l f a c t o r y e p i t h e l i u m : u p p e r 1 / 3
r d
o f
n a s a l c a v i t y a b o v e t h e s u p e r i o r
t u r b i n a t e
• R e s p i r a t o r y e p i t h e l i u m ( p s e u d o -

29. L y m p h a t i c D r a i n a g e
1 . E x t e r n a l n o s e & a n t e r i o r n a s a l c a v i t y
⇒ S u b m a n d i b u l a r l y m p h n o d e s
2 . R e m a i n i n g n a s a l c a v i t y
⇒ U p p e r d e e p c e r v i c a l l y m p h n o d e s
3 . N a s a l r o o f ( d a n g e r o u s a r e a o f n o s e )
⇒ S u b a r a c h n o i d s p a c e a l o n g t h e
o l f a c t o r y n e r v e

30. P a r a n a s a l S i n u s e s
• A n t e r i o r g r o u p
• F r o n t a l
• A n t e r i o r e t h m o i d a l
• M a x i l l a r y
• P o s t e r i o r g r o u p
• P o s t e r i o r e t h m o i d a l
• S p h e n o i d

33. D e v e l o p m e n t o f P . N . S .
A p p e a r
f i r s t
F i r s t X - r a y
a p p e a r a n c
e
R e a c h
a d u l t s i z e
b y
M a x i l l a r y A t b i r t h 4 m t h 1 5 y r
E t h m o i d a l A t b i r t h 1 y r 1 2 y r
S p h e n o i d 2 y r 4 y r 1 8 y r
F r o n t a l 4 y r 6 y r 1 5 y r

34. P h y s i o l o g y o f
N o s e & P N S ,
O l f a c t i o n

35. F u n c t i o n s o f N o s e
• Respiration
– H e a t e x c h a n g e
– H u m i d i f i c a t i o n
– F i l t r a t i o n
– N a s a l r e s i s t a n c e
– N a s a l f l u i d s & c i l i a r y f u n c t i o n
– N a s a l n e u r o v a s c u l a r r e f l e x e s
– V o i c e m o d i f i c a t i o n
• Olfaction

36. F u n c t i o n s o f P N S
• Vocal resonance
• Air conditioning of the inspired air
• Pressure damper
• Reduction of skull weight
• Floatation of skull in water
• Increasing the olfactory area

37. Respiration
• Inspiration
– A i r c u r r e n t p a s s e s a l o n g m i d - p o r t i o n o f
n a s a l c a v i t y i n l a m e l l a r f l o w
• Expiration
– R e s i s t a n c e o f n a s a l v a l v e & t u r b i n a t e s
l e a d s t o f o r m a t i o n o f e d d y c u r r e n t i n
e x p i r e d a i r

38. R e s p i r a t i o n

39. A i r c o n d i t i o n i n g
• Filtration : Particles > 3 μm in inspired air are
trapped by nasal vibrissae
• Temperature control
– H e a t e x c h a n g e b e t w e e n b l o o d i n
c a v e r n o u s v e n o u s s i n u s o i d s o f
t u r b i n a t e s & i n s p i r e d a i r ,
( r a d i a t i o n )
• Humidification
– s e c r e t i o n s o f n a s a l & P N S
m u c o s a ; f o r b e t t e r c i l i a r y

40. Protection of lower airway
• Muco-ciliary blanket: traps pathogens in
inspired air > 0.5 μm & transports them to
nasopharynx for swallowing
• Sneezing: protects against irritants
• Lysozyme: kills bacteria & viruses
• Immunoglobulins A & E :protection against
bacteria

41. Muco-ciliary blanket
• Goblet cells in nasal mucosa secrete a
mucous blanket that moves backwards
like a conveyer belt into the
nasopharynx
• Consists of
–
–
S u p e r f i c i a l m u c o u s o r g e l l a y e r
D e e p s e r o u s o r s o l l a y e r

42. Muco-ciliary blanket
G e
l
S o l

44. Ciliary cycle

45. Factors decreasing mucociliary function
• Dry atmosphere (absence of humidity)
• Smoking, air pollutants & nasal irritants
• Infection
• Extremes of temperature
• Hypoxia
• Drugs: anesthetics, sedatives, topical nasal
decongestants, beta blockers

46. V e n t i l a t i o n o f P N S
• Inspiration
–N e g a t i v e p r e s s u r e c r e a t e d i n
n a s a l
f r o m
c a v i t y s u c k s o u t
s i n u s e s
a i r
v i a
p a r a n a s a l
t h e i r o s t i u m
• Expiration
–E d d i e s
w i t h i n n a s a l c a v i t y
c r e a t e p o s i t i v e p r e s s u r e t h a t
v e n t i l a t e s p a r a n a s a l s i n u s e s

47. Ventilation of PNS

48. D r a i n a g e o f s i n u s e s

49. • Anterior sinuses
drain in lateral
pharyngeal gutter
• Posterior sinuses
drain over posterior
pharyngeal wall

50. N a s a l r e s i s t a n c e
Nasal resistance to
expired air ( by
nasal valve) keeps
positive pressure in
respiratory tract &
prevents alveolar

51. V o c a l R e s o n a n c e
• Nasal cavity & paranasal sinuses provide vocal
resonance for nasal consonants M, N, nG
• De-nasal voice( Hyponasal Voice)
– S e e n i n n a s a l o b s t r u c t i o n
– N a s a l c o n s o n a n t s M , N & n G
p r o n o u n c e d a s B , D & G
r e s p e c t i v e l y

52. N a s a l R e f l e x e s
• Smell reflex : Increases secretions of saliva &
gastric juice
• Naso-pulmonary reflex : Chronic, severe nasal
obstruction leads to increased pulmonary
resistance and pulmonary hypertension
• Sneeze reflex : Protection against F.B., irritants

53. Nasal Cycle
• Reflex, periodic alternation in nasal airflow
resistance between two nasal cavities
• Regulated by autonomic nervous system
• Due to congestion & decongestion of venous
sinusoids of inferior turbinates & anterior nasal
septum
• Each cycle lasts for 4-12 hours

54. F a c t o r s m o d i f y i n g n a s a l
c y c l e
• Temperature & humidity of surrounding air
• Head position
• Body temperature
• Physical activity
• Emotional & psychological status
• Hypothyroidism & hyperthyroidism
• Nasal decongestants & anti- hypertensives

55. Olfaction

56. O l f a c t o r y a r e a o f n o s e
•L o c a t e d o n t h e
r o o f o f t h e
n a s a l c a v i t y
•S u p e r i o r p a r t o f
t h e n a s a l s e p t u m
•C r i b r i f o r m p l a t e
•S u p e r i o r t u r b i n a t e
•U p p e r p a r t o f m i d d l e
t u r b i n a t e

57. O l f a c t o r y n e u r a l
p a t h w a y
Olfactory receptors on nasal mucosa → Olfactory
nerve bundles (20) → synapse with Mitral &
Tufted cells in Olfactory bulb → Axons unite to
form Olfactory tract → flattens distally to form
Olfactory trigone → trifurcates into Olfactory
striae → synapse with 1 & 2 Olfactory cortex +
0 0

60. • Olfaction is the only sensation to reach
cerebral cortex directly without first relaying at
thalamus
• Olfactory pathway incorporates limbic system
& is concerned with emotional behaviour,
mood & recent memory

61. C a u s e s o f O l f a c t o r y
d y s f u n c t i o n
1. Upper respiratory viral infection (30 %)
2. Idiopathic (25 %)
3. Head trauma (20 %)
4. Obstructive sinonasal disease (15 %)
• Rhino-sinusitis , nasal polyp , neoplasm
5. Neurologic & Psychiatric diseases
6. Intra-cranial neoplasm

62. C l a s s i f i c a t i o n
• Conductive loss: obstruction of nasal passages
– C h r o n i c n a s a l i n f l a m m a t i o n ,
p o l y p o s i s
• Sensorineural loss: damage to neuroepithelium
– V i r a l i n f e c t i o n , a i r b o r n e t o x i n
• Central olfactory neural loss: C.N.S. damage

63. T y p e s o f O l f a c t o r y d y s f u n c t i o n
1. Anosmia: absence of olfactory sensation
2. Hyposmia: decreased olfactory sensation
3. Parosmia / cachosmia: perception of a
pleasant odour as unpleasant odour
4. Phantosmia: perception of odour in
absence of olfactory stimulus
5. Hyperosmia: increased olfactory sensation

64. O l f a c t o r y f u n c t i o n t e s t s
1. Supra-threshold test: only identifies odour
• Smell bottles
• Smell Identification Test (S.I.T.)
2. Threshold Olfactometry: measures weakest
perceptible odour with help of serial dilution
• Manual
• Dynamic (automated)

65. M a n u a l T h r e s h o l d
O l f a c t o m e t r y

66. D y n a m i c T h r e s h o l d
O l f a c t o m e t r y

67. University of Pennsylvania Smell
Identification Test (UPSIT)
• Most commonly used test of smell worldwide
• 4 booklets of 10 microencapsulated odors
stimuli
• Scratch and sniff format
• Four responses accompanying each odor
• Forced choice design

68. S m e l l I d e n t i f i c a t i o n T e s t
s a m p l e

69. Results
36 – 40 :Normal
16-35 :Partial anosmia
6-15 :Total anosmia
0-5 :Malingering
Thank you !