Airway anatomy

Question 1

What structures make up the airway

Answer 1

1. oral cavity
2. nasal cavity
3. pharynx
4. larynx
5. trachea
6. principal bronchi

Question 2

5 components of upper airway

Answer 2

1. nose
2. nasopharynx
3. oropharynx
4. laryngopharynx
5. larynx

Question 3

What is a patient response to too long of an oral airway?

Answer 3

laryngospam

Question 4

Where does the airway begin?

Answer 4

nares

Question 5

What is the nose’s function?

Answer 5

1. air movement
2. humidification
3. olfaction
4. filtration
5. phonation

Question 6

What is the length from nostrils to nasopharynx in an adult?

Answer 6

10-14cm

Question 7

What is the primary pathway for normal breathing?

Answer 7

Nose- unless obstruction is present

Question 8

Sensory innervation of the nasal mucosa arises from what?

Answer 8

2 divisions of the trigeminal nerve

anterior ethmoidal nerve- supplies anterior septum and lateral wall

nasopalatine nerves from sphenopalatine ganglion- where posterior areas are innervated

Question 9

Blood supply to the nose consists of

Answer 9

opthalmic artery- upper part of nasal cavity

maxillary artery- lower part of nasal cavity

Kiesselbach’s plexus- anastomoses of 4 small arteries (very vascular, origination of most nose bleeds)

large submucous venous plexus

Question 10

Nerve supply to the nose consists of

Answer 10

1. olfactory
2. 1st division of V (opthalmic nerve)
3. 2nd division of V (maxillary nerve)
4. sphenopalatine ganglion (behind turbinates)

Question 11

Nasal intubation

Answer 11

1. use topical vasoconstrictor and local anesthetic
2. stay below inferior turbinate-parallel to hard palate (follow floor of nasal cavity)
3. lubricate tube with warm water and use nasal trumpet to dilates nares

Question 12

The pharyngeal anatomy consists of

Answer 12

1. nasopharynx- behind nasal cavity, above soft palate
2. oropharynx- soft palate to tip of epiglottis
3. laryngopharynx- tip of epiglottis to lower border of cricoid cartilage at level of C-6

Question 13

Describe the pharyngeal airway

Answer 13

1. extends from posterior aspect of the nose down to cricoid cartilage
2. extends from spenoid bone to C-6
3. retropharyngeal space permits free glutition and retropharyngeal abcesses can infiltrate this space and enter superior mediastinum

Question 14

Name the muscles of the pharynx

Answer 14

1. genioglossus- protrudes tongue
2. geniohyoid- displaces hyoid arch anterior
3. sternohyoid- displaces hyoid arch anterior
4. pharyngeal constrictors- form lateral pharyngeal walls

external muscles- constrictors superior, middle, and inferior (advance food down esophagus)

internal- stylopharyngeus, salpinopharyngeus, palatopharyngeous

Question 15

Pharyngeal innervation

Answer 15

glossopharyngeal, vagus, recurrent, and external laryngeal

glossopharyngeal provides nerve sensation to back 1/3 of tongue, valleculae, superior surface of epiglottis, and most of posterior pharynx

Question 16

SUccessful airway management amounts to preventing airway obstruction at what level?

Answer 16

Pharynx b/c its decreased by sedation, lost by neuromusular blockade and general anesthesia

Question 17

Order of importance for upper airway obstruction

Answer 17

1. soft palate
2. epiglottis
3. tongue

Question 18

What muscle is important when considering patients with obstructive sleep apnea (OSA)

Answer 18

genioglossus- may need to insert oral airway

Question 19

Tongue motor innervation

Answer 19

hypoglossal, except for palatoglossus muscle (vagus CN10)

Question 20

Tongue sensory innervation

Answer 20

1. lingual
2. chorda tympani
3. glosspharyngeal (CN9)
4. superior laryngeal

Question 21

Tongue blood supply

Answer 21

lingual artery- branch of external carotid

Question 22

Describe numbering system for dentation

Answer 22

number 1 is upper right to 16 upper left, 17 lower left to 32 lower right

Question 23

Structures within the larynx include

Answer 23

1. hyoid bone
2. thyroid cartilage
3. cricoid and arytenoid cartilages
4. tracheal cartilages
5. cricoid cartilages

Question 24

Name the 9 cartilages in the larynx

Answer 24

unpaired- thyroid, cricoid, epiglottis

paired- arytenoids, cuneiforms, corniculates

Question 25

Where is the cricothyroid membrane

Answer 25

Between thyroid and cricoid cartilages- this is the place for puncture during emergent intubation

Question 26

What do extrinsic and intrinsic muscles within the larynx move?

Answer 26

extrinsic- move entire larynx intrinsic- move individual cartilages (abductors and adductors) *abduction during inspiration, partial adduction during expiration, and full abduction during phonation

Question 27

Intrinsic muscles within the larynx include

Answer 27

1. interarytenoid 2. lateral cricoarytenoid 3. posterior cricoarytenoid 4. cricothyroid 5. thyroarytenoid (true vocal cord) muscle

Question 28

All intrinsic muscles work to adduct the vocal cords except

Answer 28

posterior cricoarytenoid- abducts vocal cords

Question 29

Name the 8 extrinsic laryngeal muscles

Answer 29

1. stylohyoid 2. mylohyoid 3. geniohyoid 4. digastric muscles 5. sternothyroid 6. sternohyoid 7. thryrohyoid 8. omohyoid muscles

Question 30

Which extrinsic muscles raise the larynx?

Answer 30

suprahyoid extrinic laryngeal muscles - stylohyoid - mylohyoid - geniohyoid - digastric muscles

Question 31

Which extrinsic muscles lower the hyoid bone and larynx?

Answer 31

infrahyoid extrinsic laryngeal muscles - sternothyroid - sternohyoid - thyrohyoid - omohyoid muscles

Question 32

Name the blood supply to the larynx

Answer 32

1. external carotids (superior laryngeal artery) | 2. subclavians (inferior laryngeal artery)

Question 33

Innervation of the larynx

Answer 33

Innervation- branches of the vagus nerve - superior laryngeal nerve - recurrent laryngeal nerve

Question 34

Sensory innervation of the larynx

Answer 34

internal branch of superior laryngeal nerve is sensory to and including surface of larynx facing pharynx, on tracheal side- receuurent laryngeal

Question 35

Motor innervation of larynx

Answer 35

all intrinsic muscles of larynx innervated by recurrent laryngeal nerve except cricothyroid, which is innervated by external branch of superior laryngeal nerve

Question 36

What is a laryngospams?

Answer 36

reflex closure of true cords (and sometimes false cords) because of stimulation of intrinsic laryngeal muscles

Question 37

Which muscles are involved in laryngospams?

Answer 37

cricothyroids (adduct and tense true cords)

Question 38

Laryngospam sensory and motor innervation

Answer 38

sensory- internal branch of superior laryngeal | motor- external branch of superior laryngeal

Question 39

What happens during laryngospams?

Answer 39

1. responsible for significant portion of post-operative critical events 2. immediate hypoxemia 3. delayed-negative pressure pulmonary edema (forceful inspiratory effort against closed glottis)

Question 40

What are laryngeal palsies?

Answer 40

when one or both of the cords are not working properly

Question 41

Unilateral superior laryngeal nerve palsy causes what sound?

Answer 41

inability to create high-pitched C

Question 42

Unilateral recurrent nerve palsy cause what sound?

Answer 42

hoarseness

Question 43

What is the most critical time to observe for airway obstruction?

Answer 43

during emergence of anesthesia

Question 44

In the absence of a foreign body airway obstruction, airway may be restored by

Answer 44

1. pulling mandible foreward 2. slightly extended patient's neck 3. sniffing position

Question 45

How can oropharyngeal obstruction by overcome?

Answer 45

positive-pressure from manual inflations from ambu-bag

Question 46

What is the trachea? How long is it? Where does it end?

Answer 46

- tubular structure that begins opposite 6th cervical vertebra at level of thyroid cartilage - 10-15cm - ends at carina (5th thoracic vertebra)

Question 47

Describe the steps of the couge mechanism.

Answer 47

1. deep inspiration to attain high lung volume 2. tight closure of glottis occurs with contraction of expiratory muscles 3. intrapleural pressure rises to above 100cm H20 such that a sudden expulsion of air occurs as glottis opens