Airway Anatomy

Question 1

3 sections of airway

Answer 1

oral cavity, pharynx, larynx

Question 2

Larynx begins and ends

Answer 2

C3 - C6

Question 3

Trachea begins and ends

Answer 3

C6 - T5

Question 4

Hypopharynx anatomy includes 3

Answer 4

1. Posterior cricoid
2. Pharyngeal wall
3. Pyriform sinuses

Question 5

CN innervation of oropharynx

Answer 5

CN V - Trigeminal
- SENSORY to anterior 2/3 of tongue
CN IX - Glossopharyngeal 
- SENSORY to posterior 1/3 of tongue
CN XII - Hypoglossal (MOTOR)
- MOTOR of tongue

Question 6

9 cartilages

Answer 6

epiglottis
thyroid c.
cricoid c.
cuneiform cs. 
corniculate cs.
arytenoid cs.

Question 7

Intrinsic muscles of the larynx

Answer 7

• posterior cricoarytenoid (abducts cords)
• lateral cricoarytenoid (adducts cords)
• arytenoids (adducts cords)
• cricothyroid (cord tension, closure, enlongates)
• thyroarytenoid (shortens & relaxes)

Question 8

Extrinsic muscles of the larynx,

2 groups

Answer 8

“Strap” muscles, depress larynx

“Up” muscles, raise larynx

Question 9

Strap muscles

Answer 9

DEPRESS larynx

1. Sternohyoid muscle
2. Sternothyroid muscle
3. omohyoid muscle

Question 10

“up” muscles

Answer 10

RAISE larynx

1. Mylohyoid muscle
2. Stylohyoid muscle
3. Thyrohyoid muscle

Question 11

Vagus nerve divides into 2 branches to innervate larynx

Answer 11

1. Superior Laryngeal Nerve (SLN)

2. Recurrent Laryngeal Nerve (RLN)

Question 12

SCAR (larynx innervation) stands for

Answer 12

SLN (innervates)
Cricothyroid muscle
All others
RLN

Question 13

Superior Laryngeal Nerve

• sensory branch
• motor branch

Answer 13

SIS (superior internal = sensory)

SEM (superior external = motor)

Question 14

Upper airway structures (5)

Answer 14

• nose
• mouth
• pharynx
• hypopharynx
• larynx

Question 15

Lower airway structures (6)

Answer 15

• trachea
• bronchi
• bronchioles
• terminal bronchioles
• respiratory bronchioles
• alveoli

Question 16

Nose function (4)

Answer 16

• leads to nasopharynx
• warms & humidifies gases
• PRIMARY pathway for breathing unless [obstruction, polyps, URI]
• nasal breathing resistance is almost 2x mouth breathing

Question 17

Mouth

Answer 17

• leads to oropharynx

- mouth breathing during high flow rates (ie. exercise)

Question 18

Pharynx is …

location…

compartments

Answer 18

U-shaped fibromuscular structure

• extends from posterior aspect of nose to the level of the cricoid cartilage

3 compartments

Question 19

3 compartments of the pharynx

Answer 19

1. nasopharynx
2. oropharynx
3. hypopharynx

Question 20

Nasopharynx borders

Answer 20

• anterior to C1
• superior border is base of skull
• inferior border is soft palate

Question 21

Nasopharynx contains (3)

Answer 21

nasal septum, turbinates, adenoids

Question 22

Airflow through the nasopharynx can be impeded by

Answer 22

tonsillar lymphoid structures

Question 23

Oropharynx borders & location

Answer 23

Lies at C2-C3

• superior border is soft palate
• inferior border is epiglottis
• posterior border is tonsillar pillars
• mouth opening is located anteriorly

Question 24

Oropharynx obstruction; major source

Answer 24

MAJOR source = tongue

d/t ↓ genioglossus muscle tone

Question 25

Hypopharynx borders

Answer 25

- superior border is epiglottis - inferior border is cricoid cartilage (@ C5-C6) - anterior border is the larynx

Question 26

_______ lies at the lower edge of the hypopharynx and acts as a barrier to regurgitation in the conscious patient

Answer 26

upper esophageal sphincter

Question 27

Waldeyer's Tonsillar Ring

Answer 27

lymphoid tissue ring [in pharynx] that is a high risk of bleeding, especially in nasal intubation

Question 28

Waldeyer's Tonsillar Ring is made up of:

Answer 28

1. Pharyngeal tonsils [aka adenoids] 2. Palatine tonsils 3. Lingual tonsils

Question 29

Vertebral level of the larynx

Answer 29

Adults: C3-C6 5yr old: C4-C5 Infants/Peds: C2-C4 [sits at the junction of the airway and the esophagus]

Question 30

Function of the larynx (2)

Answer 30

1. phonation | 2. valve to protect lower airways

Question 31

Larynx borders

Answer 31

- superior border is underside of epiglottis - inferior border is lower level of the cricoid cartilage - posterior border is the mucous membrane [extends between arytenoid cartilage & the aryepiglottic folds (aka false vocal cords)]

Question 32

aryepiglottic cords AKA

Answer 32

false vocal cords

Question 33

Trachea location

Answer 33

beings at C6 [inferior border of cricoid cartilage] ends at ~T5 [carina[ ~10-15cm in length 16-20 cartilaginous anterior rings

Question 34

Bifurcation of Right bronchus

Answer 34

@ 25-30 degree angle

Question 35

Bifurcation of Left bronchus

Answer 35

@ 45 degree angle

Question 36

Infant/Pediatric anatomical differences [general] (3)

Answer 36

- Head & occiput larger relative to body size - Short neck - Narrow nares

Question 37

Infant/Pediatric airway anatomical differences (4)

Answer 37

- tongue relatively larger - larynx positioned higher in neck - epiglottis larger, stiffer, angled more posteriorly - cricoid ring is the NARROWEST region

Question 38

components that protect the lower airway from aspiration (3)

Answer 38

1. pharynx 2. epiglottis 3. vocal cords * MOST IMPORTANT MECHANISM IS THE GLOTTIC CLOSURE REFLEX

Question 39

*most important* mechanism of airway protection

Answer 39

glottic closure reflex

Question 40

Laryngospasm

Answer 40

prolonged, intense glottic closure and an exaggeration of glottic closure reflex

Question 41

hyperextension of neck in peds

Answer 41

pushes posterior pharyngeal wall up against tongue & epiglottis

Question 42

Posterior cricoarytenoid muscle is the only muscle.....

Answer 42

that abducts the vocal cords

Question 43

Unilateral SLN damage results in

Answer 43

minimal effects

Question 44

Bilateral SLN damage results in:

Answer 44

hoarseness, vocal tiring

Question 45

Unilateral RLN damage results in:

Answer 45

hoarseness

Question 46

Bilateral RLN damage results in: | Acute vs chronic

Answer 46

Acute: stridor, respiratory distress d/t unopposed adduction/tension from the cricothyroid muscle Chronic: Aphonia

Question 47

Vagus nerve damage effect on vocal cords

Answer 47

*both SLN & RLN will be affected flaccid, mid-positioned cords = aphonia

Question 48

Surgeries most likely to damage RLN

Answer 48

thyroid & carotid