Unit 1 - Airway Anatomy Flashcards

1
Q

function of intrinsic laryngeal muscles

A

participate in phonation and control vocal cords (tension and position)

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2
Q

function of extrinsic laryngeal muscles

A

support larynx inside neck, assist with swallowing

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3
Q

function & innervation of cricothyroid muscle

A

function: elongates (tenses) vocal cords
- CricoThyroid “Cords Tense”

innervation: SLN extenal branch

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4
Q

function & innervation of vocalis muscle

A

function: shortens (relaxes) vocal cords

innervation: RLN

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5
Q

function & innervation of thyroarytenoid muscle

A

function: shortens (relaxes) vocal cords, ADDucts vocal folds (closes glottis)
- ThyroaRytenoid “They Relax”

innervation: RLN

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6
Q

function & innervation of lateral cricoarytenoid muscle

A

function: ADDucts vocal folds (closes glottis)
- Lateral CricoArytenoid “Lets Close Airway”

innervation: RLN

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7
Q

function & innervation of posterior cricoarytenoid muscle

A

function: ABducts vocal folds (opens glottis)
- Posterior CricoArytenoid “Please Come Apart”

innervation: RLN

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8
Q

function & innervation of aryepiglottic muscle

A

function: closes laryngeal vestibule

innervation: RLN

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9
Q

function & innervation of interarytenoid muscles (transverse & oblique)

A

function: closes posterior commissure of glottis

innervation: RLN

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10
Q

laryngeal muscles that adjust length (tension) of vocal ligaments

A
  • cricothyroid (elongates/tenses)
  • vocalis (shortens/relaxes)
  • thyroarytenoid (shortens/relaxes)
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11
Q

laryngeal muscles that ABduct or ADDuct vocal folds (glottic diameter)

A
  • thyroarytenoid (ADDucts/narrows glottis)
  • lateral cricoarytenoid (ADDucts/narrows glottis)
  • posterior cricoarytenoid (ABducts/widens glottis)
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12
Q

laryngeal muscles that control sphincter muscle

A
  • aryepiglottic: closes laryngeal vestibule
  • interarytenoid: closes posterior commissure of glottis
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13
Q

extrinsic function of cricothyroid muscles

A

contraction during swallowing pulls anterior region of cricoid cartilage towards lower border of thyroid cartilage

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14
Q

extrinsic laryngeal muscles

A

all end in -hyoid except digastric

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15
Q

risk factors for RLN injury

A
  • external pressure from ETT or LMA
  • thyroid or parathyroid surgery
  • neck stretching
  • neoplasm
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16
Q

provides sensory innervation to face

A

CN 5 (trigeminal n.)

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17
Q

branches of trigeminal nerve

A

V1 - opthalmic nerve
V2 - maxillary nerve
V3 - mandibular nerve

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18
Q

nerve that innervates the nares and anterior 1/3rd of nasal septum

A

anterior ethmoidal nerve (branch of V1 opthalmic nerve)

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19
Q

innervates turbinates and posterior 2/3 of nasal septum

A

sphenopalatine nerve (branch of V2 maxillary nerve)

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20
Q

provides sensory innervation to anterior 2/3 of tongue

A

V2 maxillary n

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21
Q

provides sensory innervation to posterior 1/3 of tongue, oropharynx, vallecula, and anterior epiglottis

A

CN IX - glossopharyngeal

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22
Q

afferent limb of gag reflex

A

CN IX - glossopharyngeal n.

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23
Q

efferent limb of gag reflex

A

CN X - Vagus n.

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24
Q

what nerve gives rise to SLN and RLN

A

CN X - vagus

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25
Q

function of internal branch of SLN

A

sensory innervation to posterior side of epiglottis to the level of vocal folds

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26
Q

function of external branch of SLN

A

motor innervation to cricothyroid muscle (tenses vocal cords)

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27
Q

symptom of acute injury to SLN trunk or external branch

A

hoarseness

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28
Q

function of RLN

A
  • sensory innervation below level of vocal folds to the trachea
  • motor innervation to all intrinsic laryngeal muscles except cricothyroid
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29
Q

where does the RLN branch off of CN X

A
  • inside thorax
  • right RLN: loops under subclavian artery
  • left RLN: loops under aortic arch
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30
Q

what part of the RLN is most susceptible to injury and why

A

left RLN - due to location in thorax

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31
Q

risk factors for left RLN injury

A
  • PDA ligation
  • left atrial enlargement (from mitral stenosis)
  • aortic arch aneurysm
  • thoracic tumor
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32
Q

s/s acute unilateral RLN injury

A
  • paralysis of ipsilateral vocal cord ABductors (unopposed ADDuctor action)
  • hoarseness
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33
Q

s/s acute bilateral RLN injury

A
  • bilateral paralysis of vocal cord ABductors
  • unopposed tension of cricothyroid
  • stridor, respiratory distress (presents similary to laryngospasm)
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34
Q

provides motor innervation to muscles of mastication

A

V3 - mandibular n. (branch of trigeminal n)

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35
Q

what nerve must be anesthetized to prevent pt from gagging during awake intubation

A

glossopharyngeal (CN IX)

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36
Q

where does the SLN branch off of the vagus n.

A

just beyond jugular foramen at skull base

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37
Q

where does the SLN divide into internal and external branches

A

at level of hyoid

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38
Q

where does the internal SLN branch penetrate thyrohyoid membrane

A

between greater cornu of hyoid bone and superior horn of thyroid cartilage

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39
Q

most common nerve injury folowing subtotal thyroidectomy

A

unilateral RLN injury

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40
Q

topical techniques to anesthetize nares

A
  • 4% lidocaine + vasoconstrictor
  • cocaine
  • topical LA in eacn nare
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41
Q

risk of using viscous lidocaine to anesthetize airway

A

N/V

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42
Q

risk of 20% benzocaine to anesthetize airway and the treatment

A

methemoglobinemia

treat with methylene blue

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43
Q

which typically works better to anesthetize airway - nebulization or atomization

A

atomization

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44
Q

3 techniques to anesthetize vocal cords

A
  1. inject LA through nasal airway or ETT just above cords
  2. “spray as you go” with fiberoptic scope
  3. inject LA through catheter in suction port of flexible fiberoptic catheter
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45
Q

3 nerves that must be blocked to provide complete anesthesia to airway

A
  1. glossopharyngeal n.
  2. superior laryngea n.
  3. recurrent laryngeal n.
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46
Q

glossopharyngeal nerve block technique

A
  1. insert needle at base of palatoglossal arch (anterior tonsillar pillar) to 0.25-0.5cm
  2. inject 1-2 mL LA and repeat on contralateral side
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47
Q

glossopharyngeal n. block - what does aspiration of air vs. blood mean

A

air: needle is too deep

blood: needle should be withdrawn and redirected medially (carotid is close)

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48
Q

risk of glossopharyngeal n block

A

5% incidence of intracarotid injection - risk of seizure

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49
Q

SLN nerve block

A
  • LA injected at inferior border of greater cornu of hyoid bone
  • 1 mL injected outside thyrohyoid membrane, 2 mL injected 2-3 mm deep to membrane
  • repeat bilaterally
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50
Q

what does air aspiration during SLN block mean

A

needle is too deep

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51
Q

RLN block

A

transtracheal approach:
- puncture cricothyroid membrane, advance needle caudally to reduce risk of vocal cord injury
- have pt take deep breath before aspiration
- during inspiration, inject 3-5 mL LA in tracheal lumen
- pt will cough and spray LA upwards through cords

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52
Q

location of adult larynx (in relation to C spine)

A

anterior to C3-C6

(infant = C2-C4)

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53
Q

3 primary functions of larynx

A
  1. airway protection
  2. respiration
  3. phonation
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54
Q

3 unpaired cartilages of the larynx

A
  1. epiglottis
  2. thyroid
  3. cricoid
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55
Q

serves as the major structural component of the larynx

A

thyroid

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56
Q

how is the thyroid attached to the hyoid bone

A

thyrohyoid ligament

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57
Q

forms inferior border of larynx

A

cricoid

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58
Q

entry point for surgical airway

A

cricothyroid membrane

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59
Q

only complete cartilaginous ring in the airway

A

cricoid

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60
Q

3 paired cartilages of the larynx

A
  1. arytenoids
  2. corniculates
  3. cuneiforms
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61
Q

serve as posterior attachment of vocal cords

A

arytenoids

62
Q

only bone in the body that does not articulate with another bone

A

hyoid bone

63
Q

why might patients with lupus or RA have increased risk of airway obstruction

A

impaired arytenoid mobility

64
Q

forms main support of larynx

A

hyoid bone

65
Q

attaches larynx (via thyroid cartilage) to hyoid bone

A

thyrohyoid ligament

66
Q

attaches cricoid and thyroid cartilages

A

cricothyroid membrane

67
Q

provides mechanical barrier between pharynx and laryngeal opening

A

epiglottis

68
Q

connects epiglottis to thyroid cartilage

A

thyroepiglottic ligament

69
Q

base articulates with cricoid cartilage to form a ball and socket joint

A

arytenoids

70
Q

provide structure to aryepiglottic folds

A

corniculate & cuneiform cartilages

71
Q

T/F - you can see arytenoids during DL

A

false

72
Q

narrowest region of the airway in adults vs. kids

A

adults - glottic opening

kids (5 and under) - narrowest fixed region is cricoid ring; narrowest dynamic region is vocal cords

73
Q

swelling of what region causes post-extubation laryngeal edema in children

A

swelling around cricoid cartilage

74
Q

what is a laryngospasm?

A

sustained and involuntary contraction of laryngeal musculature that results in inability to ventilate

75
Q

complications of laryngospasm

A
  • airway obstruction
  • NPPE
  • aspiration
  • Dysrhythmias
  • cardiac arrest
76
Q

s/s laryngospasm

A
  • stridor
  • suprasternal & supraclavicular retraction with inspiration
  • “rocking horse” breathing
  • increased diaphragmatic excursion
  • lower rib flailing
  • absent/altered EtCO2 waveform
77
Q

pre-anesthetic risk factors for laryngospasm

A
  • active URI
  • URI within past 2 weeks
  • 2nd hand smoke exposure
  • reactive airway
  • GERD
  • age < 1 year
78
Q

intraop risk factors for laryngospasm

A
  • light anesthesia (esp. with concurrent airway manipulation)
  • saliva or blood in upper airway
  • hyperventilation/hypocapnea
  • surgical procedures of airway: tonsillectomy, adenoidectomy, nasal/sinus, laryngoscopy, bronchoscopy, palatal
79
Q

duration of laryngeal lidocaine

A

~30 minutes

80
Q

treatment of laryngospasm

A
  • 100% FiO2
  • remove noxious stim
  • deepen anesthesia (volatile, propofol, lidocaine)
  • CPAP 15-20 cm H2O
  • head extension, chin lift, Larson’s
  • succs
81
Q

dosing of succs for laryngospasm

A

IV:
- neonate = 2 mg/kg
- adult or child = 1 mg/kg

IM:
- neonate or infant = 5 mg/kg
- adult or child = 4 mg/kg

82
Q

site of fastest onset of IM succs

A

submental

83
Q

only NMBs that can be given IM

A
  • succs
  • roc
84
Q

what med shold be co-administered with succs in kids < 5 yrs old

A

atropine 0.02 mg/kg to prevent bradycardia

85
Q

what is Larson’s maneuver?

what does it accomplish?

A

application of bilateral firm pressure to the notch just behind the earlobe

accomplishes 2 things:
1) displaces mandible anteriorly to open airway
2) breaks laryngospasm by causing lightly anesthetized patient to sigh

86
Q

how to apply Larson’s maneuver

A

apply pressure for 3-5 seconds then release for 5-10 seconds
repeat until laryngospasm breaks

87
Q

what is valsalva’s maneuver? what are the risks?

A
  • exhalation against a closed glottis (obstruction)
  • ex: coughing, bucking, bearing down
  • risk: increased pressure in thorax, abdomen, brain
88
Q

Muller’s maneuver and risks

A
  • inhalation against closed glottis (obstruction)
  • ex: patient bites down on ETT and takes deep breath
  • risk: subatmospheric pressure in thorax, NPPE
89
Q

3 places the upper airway can obstruct during anesthesia

A
  • soft palate
  • tongue
  • epiglottis
90
Q

relaxation of the tensor palatine muscle can cause obstruction in which part of the airway?

A

soft palate

91
Q

relaxation of the genioglossus muscle can cause obstruction in which part of the airway?

A

tongue

92
Q

relaxation of the hyoid muscles can cause obstruction in which part of the airway?

A

epiglottis

93
Q

why should the bevel be towards the turbinates with nasal instrumentation (ex. nasal airway)

A

ensures leading edge travels along septum, where it’s less likely to traumatize turbinates

94
Q

why do patients in respiratory failure convert to mouth breathing?

A

scroll-like shape of nasal turbinates = high degree of airway resistance

95
Q

Methods to remedy obstruction related to genioglossus muscle relaxation

A
  • jaw thrust
  • oral airway
96
Q

what connects the oral and nasal cavities with larynx and esophagus

A

pharynx

97
Q

contraction of which muscles helps to maintain airway patency

A

pharyngeal dilators

98
Q

method to alleviate airway obstruction caused by relaxation of pharyngeal dilator muscles

A

chin lift with a closed mouth

99
Q

where are the adenoid tonsils located

A

superior and posterior walls of nasopharynx

100
Q

how can lingual tonsils affect airway DL and airway placement

A

hypertrophy can hinder DL or impair seating of supraglottig airway device

101
Q

what all is included in the upper airway

A

mouth and nares to cricoid cartilage

102
Q

3 primary functions of the upper airway

A
  1. warming & humidifying inspired air
  2. filtering particulate matter
  3. preventing aspiration
103
Q

3 sets of dilator muscles that counteract tendency for airway collapse in awake patients

A
  1. tensor palatine
  2. genioglossus
  3. hyoid muscles
104
Q

function of tensor palatine muscle

A

opens nasopharynx

105
Q

function of genioglossus muscle

A

opens oropharynx

106
Q

function of hyoid muscles

A

opens hypopharynx

107
Q

where does the trachea begin and end

A
  • begins at inferior border of cricoid cartilage
  • teminates at carina (~T4-T5)
108
Q

what are the bifurcations off of the carina?

A

right and left mainstem bronchi

109
Q

why is endobronchial intubation more likely to occur on the right side?

A

less acute angle (25 deg)

110
Q

Why do right sided DLTs require meticulous positioning?

A

The takeoff to RUL is only 2.5 cm from the carina

111
Q

where does the lower airway begin and end

A
  • begins at trachea
  • ends at alveoli
112
Q

what vertebral level corresponds with the adult trachea

A

C6

113
Q

allows air movement between alveoli

A

pores of Kahn

114
Q

sensory innervation of the trachea

A

vagus n.

115
Q

blood supply to the trachea

A
  • inferior thyroid artery
  • superior thyroid artery
  • bronchial artery
  • internal thoracic artery
116
Q

what part of the airway corresponds with the angle of Louis

A

carina

117
Q

type of cells in the trachea

A

ciliated columnar epithelium

118
Q

type of cells in the alveoli

A

squamous epithelium

119
Q

type of cells in carina

A

ciliated columnar epithelium

120
Q

function of type 1 pneumocytes

A

provide surface for gas exchange

121
Q

type of cells that cover ~80% of alveolar surface

A

type 1 pneumocytes

122
Q

what type of pneumocytes are resistant to oxygen toxicity

A

type II

123
Q

what type of pneumocytes are macrophages

A

type III

124
Q

when are neutrophils present in the alveoli?

A
  • smokers
  • acute lung injury
125
Q

how long is the right vs. left mainstem bronchi

A

right: 2.5 cm long
left: 5 cm long

126
Q

function of type 3 pneumocytes

A
  • fight lung infection
  • produce inflammatory response
127
Q

how wide is the trachea

A

2.5 cm

128
Q

distance from incisors to larynx

A

~13 cm

129
Q

distance from larynx to carina

A

~13 cm

130
Q

distance from incisors to carina

A

~26 cm

131
Q

what explains why neck positioning can cause endobronchial intubation or inadvertent extubation

A

neck flexion makes distance from incisors to carina shorter, extension makes the distance longer

132
Q

degree of R and L mainstem bronchi in children < 3 yrs

A

both take off 55 degrees from long axis of trachea

133
Q

what happens to # airways and total cross sectional area as airway bifurcates

A

increase

134
Q

4 things that decrease as airway bifurcates

A
  • airflow velocity
  • amount of cartilage
  • goblet cells
  • ciliated cells
135
Q

function of goblet cells

A

produce mucus

136
Q

function of ciliated cells

A

clear mucus

137
Q

what type of pneumocyte produces surfactant?

A

type 2

138
Q

what 2 landmarks correspond with the carina

A

T4-5

angle of louis

139
Q

solely responsible for opening vocal cords

A

posterior cricoarytenoid

140
Q

most common cause of RLN injury

A

thyroid surgery

141
Q

most caudal cartilage in larynx

A

cricoid

142
Q

most common cause of RLN injury

A

thyroid surgery

143
Q

layngeal cartilages most superior to most inferior

A

epiglottis
corniculate
arytenoid
cricoid

144
Q

afferent limb of laryngospasm

A

SLN internal branch

145
Q

efferent limb of laryngospasm

A

external SLN, RLN

146
Q

adult trachea length

A

10-13 cm

147
Q

landmarks for larson’s maneuver

A

posterior = mastoid process
superior = skull base
anterior = ramus of mandible

148
Q

function of muscle in pink

A

elongates (tenses) vocal cords

cricothyroid

149
Q

function of muscle in green

A

shortens/relaxes vocal cords
adducts vocal folds (closes glottis)

thyroarytenoid

150
Q

function of muscle in blue

A

ADDucts vocal folds (closes glottis)

lateral cricoarytenoid

151
Q

function of muscle in orange

A

ABducts vocal folds (opens glottis)

posterior cricoarytenoid

152
Q

function of muscle in purple

A

shortens (relaxes) vocal cords

vocalis