Anatomy of airway

upper/lower airway anatomy

1. ANATOMY OF AIRWAY AND
TRACHEOBRONCHIAL TREE
Dr.zikrullah
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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
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4. NOSE
Airway functionally begins at the nares , where
air first enters the body.
Septal cartilage divides nasal cavity into two
nasal fossae
ROOF-cribriformplate 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.
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5. Nasal septum is often deviated from
the midline causing one cavity to be
larger than the other .
It is therefore essential for
anaesthetistto visualize the nasal
cavity before attempting nasal
intubation
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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
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7. PHARYNX
Extends from base of skull to lower border
of cricoid cartilage.
Subdivided into: nasopharynx,
oropharynx, laryngopharynx
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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
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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
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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 .
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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
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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 rimaglottidisduring
swallowing (glottis=cords & space)
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16. THYROID CARTILAGE
Largest of the laryngeal cartilages
Inner side are attached the vocal cords
Its two alaemeet ant.
at 90
0
angle in males
120
0
angle in females
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17. CRICOID
A complete cartilaginous ring
Narrowest portion of the lower airway in
neonate and infant
Actual start of the lower airway
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18. Larynx Posterior view
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LARYNX
The thyrohyoid
membrane forms a C-
shaped barrier around the
anterior and lateral walls
of the supraglottis
Cricothyroidmembrane-
easily
palpable,avascular,sitefor
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
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The arytenoidcartilages are pyramid-
shaped and articulate with the superior
margin of the cricoidlamina. On their
summit, are the corniculatecartilages; on
their anterior aspect, are the cuneiform
cartilages

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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
arytenocorniculatecomplex.

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View of the larynx at laryngoscopy.

24. INTRINSIC MUSCULATURE
Posterior
cricoarytenoid
Abductor of vocal
cords
Recurrent laryngeal
Lateral cricoarytenoidAdducts arytenoids
closing glottis
Recurrent laryngeal
Transverse arytenoid/
posteriorcricoarytenoid
Adducts arytenoids Recurrent laryngeal
Oblique arytenoid Closes glottis Recurrent laryngeal
Thyroarytenoid Relaxescords Recurrent laryngeal
Cricothyroid Tensor of the cords External laryngeal
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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.exceptthe cricothyroid.
Cricothyroid:suppliedby external laryngeal n. (b. of
superior laryngeal n.)
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26. Superior Laryngeal nerve Paralysis
Unilateral:
Voice weak,Pitchcan not raised,
Anaesthesiaof larynx on side may cause
aspiration
Bilateral:
Voice weak ,husky
Inhalation of food and Pharyngeal secretions
lead to cough & choking .
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27. Superior and Recurrent laryngeal nerve
paralysis
Unilateral:
Hoarsnessof voice and aspiration of liquid,
cough is ineffective
Bilateral:
Aphonia, Aspiration,Inabilityto cough
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Laryngeal function: Airway Protection
Open Closed
The glottis: open for inspiration and closed for swallowing

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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
Subsegmentalbronchi
Bronchioles
Terminal bronchioles
Respiratory
bronchioles
Alveolar ducts
Alveolar sacs
alveoli
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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
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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 oedema1cm
smaller diameter ETT used.
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33. TracheobronchialTree
Series of branching airways commonly referred to
a “generations” or “orders”
The first generation or order is zero (0), the
trachea itself.
Bifucratesat the carina
Touching of carina during intubation may lead to
vagal stimulation.
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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
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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
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38. Segmental Bronchi
3
rd
generation
R lobar divides into
Segmental bronchi
10 segments on right
L lobar divides into
Segmental bronchi
10 segments on left
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39. SubsegmentalBronchi
4
th
to 9
th
generations
Progressively smaller airways
1-4 mm diameter
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40. NoncartilagenousAirways
Bronchioles
10-th to 15
th
generation
Cartilage is
absent
Surrounded by
spiral muscle
fiber
With no
cartilage, airway
remains open
due to pressure
gradients
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41. Terminal Bronchioles
16
th
to 19
th
generation
Average diameter is 0.5 mm
Cilia and mucous glands begin to
disappear totally
End of the conducting airway
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42. Gas exchange zone
Respiratory bronchioles
Acinus-respiratory bronchioles to the
alveoli
Ducts, sacs, alveoli
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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 70m
2
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44. Intersitium/interstialspace
Surround, supports, and shapes the alveoli
and capillaries
Composed of a gel like substance and
collagen fibers
Contains tight space and loose space
areas
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