upper/lower airway anatomy

1. ANATOMY OF AIRWAY AND
TRACHEOBRONCHIAL TREE
Dr.zikrullah 1

2. 2
THE UPPER AIRWAY
The upper airway starts :
 At the nostrils, extends
through the nasal conchae to
the nasopharynx, over the
uvula to the hypo pharynx
and larynx
 At the lips, extends through
the oral cavity, over the
tongue and below the hard
and soft palates, to the hypo
pharynx and larynx.

3. UPPER AIRWAY
 Nose
 Pharynx
 Larynx
3

4. NOSE
 Airway functionally begins at the nares , where
air first enters the body.
 Septal cartilage divides nasal cavity into two
nasal fossae
 ROOF-cribriform plate of the ethmoid
 FLOOR-perpendicular to the face
 LATERAL-3 turbinates
 Little’s area on anterior & inferior part of
septum; may bleed during nasal intubation
or introducing nasal airway.
4

5.  Nasal septum is often deviated from
the midline causing one cavity to be
larger than the other .
 It is therefore essential for
anaesthetist to visualize the nasal
cavity before attempting nasal
intubation
5

6. ORAL CAVITY
 Alternate respiratory passage
 Extends from mouth opening to anterior
tonsillar pillars.
 Contracture of mouth & lips-difficult
laryngoscopy.
 Teeth loose or buck-difficult intubation
6

7. PHARYNX
 Extends from base of skull to lower border
of cricoid cartilage.
 Subdivided into: nasopharynx,
oropharynx, laryngopharynx
7

8. NASOPHARYNX
 Extends from posterior end of turbinates
to posterior pharyngeal wall above soft
palate.
 Filters bacteria and foreign particles from
inspired air
 Eustachian tube open into lateral surfaces,
and connect nasopharynx to middle ear,
each equalizes pressure of middle ear
8

9. NASOPHARYNGEAL AIRWAYS
 Measuring an Airway
Measured against the distance from the patient's
nose to the patient's earlobe.

10. OROPHARYNX
 Extends from soft palate above to
epiglottis below& anteriorly from anterior
tonsillar pillar to posterior pharyngeal wall.
 Mainly has a digestive function
 Ring of waldeyer
10

11. OROPHARYNGEAL AIRWAYS
 Measuring an Airway
Corner of the mouth to tip of the ear

12. LARYNGOPHARYNX
 Lies between the fourth and sixth cervical
vertebrae.
 Starts at the superior border of the epiglottis,
and extends to the inferior border of the cricoid
cartilage, where it narrows and becomes
continuous with the oesophagus .
12

13. LARYNX
 Lies between base of tongue and trachea
 Primary function is to serve as the
“watchdog” of the respiratory tract,
allowing passage only to air
 Houses the vocal cords, and helps in
vocalization
 Connection point-upper and lower airways
 Extends from C3 to C6
13

14. 14
 Composed of 3
single cartilaginous
structures:
 Epiglottis-flap,
swings down to
meet larynx during
swallowing
 Thyroid-bulk of this
forms larynx
 Cricoid-circular

15. EPIGLOTTIS
 Covers the rima glottidis during
swallowing (glottis=cords & space)
15

16. THYROID CARTILAGE
 Largest of the laryngeal cartilages
 Inner side are attached the vocal cords
 Its two alae meet ant.
 at 900angle in males
 1200angle in females
16

17. CRICOID
 A complete cartilaginous ring
 Narrowest portion of the lower airway in
neonate and infant
 Actual start of the lower airway
17

18. Larynx Posterior view
18

19. 19
LARYNX
 The thyrohyoid
membrane forms a C-
shaped barrier around the
anterior and lateral walls
of the supraglottis
 Cricothyroid membrane-
easily
palpable,avascular,site for
surgical cricothyrotomy.

20. The Larynx: Anatomy
 The six smaller cartilages of the larynx (3 pairs)
are functionally involved with the movements of
the vocal cords.These are:
 The Arytenoids
 The Corniculates
 The Cuneiforms
20

21. 21
 The arytenoid cartilages are pyramid-
shaped and articulate with the superior
margin of the cricoid lamina. On their
summit, are the corniculate cartilages; on
their anterior aspect, are the cuneiform
cartilages

22. 22
The Larynx: Anatomy
 The vocal ligaments, are
attached posteriorly to the
apex of the arytenoids and
corniculates.
 The cuneiforms extend
laterally, between the layers
of the vocal cords, from the
anterior aspect of the
arytenocorniculate complex.

23. 23
View of the larynx at laryngoscopy.

24. INTRINSIC MUSCULATURE
Posterior
cricoarytenoid
Abductor of vocal
cords
Recurrent laryngeal
Lateral cricoarytenoid Adducts arytenoids
closing glottis
Recurrent laryngeal
Transverse arytenoid/
posterior cricoarytenoid
Adducts arytenoids Recurrent laryngeal
Oblique arytenoid Closes glottis Recurrent laryngeal
Thyroarytenoid Relaxes cords Recurrent laryngeal
Cricothyroid Tensor of the cords External laryngeal
24

25. LARYNX NERVE SUPPLY
 SENSORY:
 Above vocal cords- internal laryngeal nerve (b. of
superior laryngeal n.)
 Below vocal cords-recurrent laryngeal nerve
 MOTOR:
 All muscles which move the larynx are supplied by
recurrent laryngeal n.except the cricothyroid.
 Cricothyroid:supplied by external laryngeal n. (b. of
superior laryngeal n.)
25

26.  Superior Laryngeal nerve Paralysis
Unilateral:
Voice weak,Pitch can not raised,
Anaesthesia of larynx on side may cause
aspiration
Bilateral:
Voice weak ,husky
Inhalation of food and Pharyngeal secretions
lead to cough & choking .
26

27.  Superior and Recurrent laryngeal nerve
paralysis
Unilateral:
Hoarsness of voice and aspiration of liquid,
cough is ineffective
Bilateral:
Aphonia, Aspiration,Inability to cough
27

28. 28
Laryngeal function: Airway Protection
Open Closed
The glottis: open for inspiration and closed for swallowing

29. 29
Laryngeal function: Phonation
Adducted: Talking Abducted: Breathing
The vocal cords: Adducted for phonation; abducted for
inspiration

30. LOWER AIRWAY
 Trachea
 Main stem bronchi
 Segmental bronchi
 Subsegmental bronchi
 Bronchioles
 Terminal bronchioles
 Respiratory
bronchioles
 Alveolar ducts
 Alveolar sacs
 alveoli
30

31. Trachea
 10-13 cm long
 Mean distance lips to carina male-28.5cm;
female- 25.2cm-----ETT fixation
 Mean distance base of nose to carina male
31cm; female 28.4cm-----ETT fixation
 1.5-2.5 cm wide
31

32.  Extends from lower border of cricoid
cartilage(C6) to carina(T5) where it
bifurcates into right & left main bronchus
 15-20 C shaped rings
 Tracheostomy done at 2-3 tracheal ring.
 ETT is placed above the carina.
 In Pregnancy due to airway oedema 1cm
smaller diameter ETT used.
32

33. Tracheobronchial Tree
 Series of branching airways commonly referred to
a “generations” or “orders”
 The first generation or order is zero (0), the
trachea itself.
 Bifucrates at the carina
 Touching of carina during intubation may lead to
vagal stimulation.
33

34. 34

35. Main Stem Bronchi
 Right bronchus
 Wider
 More vertical
 5 cm long
 Supported by C
shaped cartilages
 20-30 degree angle
 First generation
 Usually bronchial
intubation, secretion &
foreign bodies lodged
 Left bronchus
 Narrower
 More angular
 5.5 cm Long
 Supported by C
shaped cartilages
 40-60 degree angle
 First generation
35

36. 36

37. Lobar Bronchi
 R main stem divides
into:
 Upper lobar bronchus
 Middle lobar bronchus
 Lower lobar bronchus
 L main stem divides
into:
 Upper lobar bronchus
 Lower lobar bronchus
37

38. Segmental Bronchi
3rd generation
 R lobar divides into
 Segmental bronchi
 10 segments on right
 L lobar divides into
 Segmental bronchi
 10 segments on left
38

39. Subsegmental Bronchi
 4th to 9th generations
 Progressively smaller airways
 1-4 mm diameter
39

40. Noncartilagenous Airways
 Bronchioles
 10-th to 15th
generation
 Cartilage is
absent
 Surrounded by
spiral muscle
fiber
 With no
cartilage, airway
remains open
due to pressure
gradients
40

41. Terminal Bronchioles
 16th to 19th generation
 Average diameter is 0.5 mm
 Cilia and mucous glands begin to
disappear totally
 End of the conducting airway
41

42. Gas exchange zone
 Respiratory bronchioles
 Acinus -respiratory bronchioles to the
alveoli
 Ducts, sacs, alveoli
42

43. Alveoli
 300 million alveoli
 Between 75 µ to 300 µ in diameter
 Most gas exchange takes place at
alveolar-capillary membrane
 85-95% of alveoli covered by small
pulmonary capillaires
 The cross-sectional area or surface area is
approximately 70m2
43

44. Intersitium/interstial space
 Surround, supports, and shapes the alveoli
and capillaries
 Composed of a gel like substance and
collagen fibers
 Contains tight space and loose space
areas
44

46. 46
THANK YOU…