Unit 1 - Airway Anatomy Flashcards
(152 cards)
1
Q
function of intrinsic laryngeal muscles
A
participate in phonation and control vocal cords (tension and position)
2
Q
function of extrinsic laryngeal muscles
A
support larynx inside neck, assist with swallowing
3
Q
function & innervation of cricothyroid muscle
A
function: elongates (tenses) vocal cords
- CricoThyroid “Cords Tense”
innervation: SLN extenal branch
4
Q
function & innervation of vocalis muscle
A
function: shortens (relaxes) vocal cords
innervation: RLN
5
Q
function & innervation of thyroarytenoid muscle
A
function: shortens (relaxes) vocal cords, ADDucts vocal folds (closes glottis)
- ThyroaRytenoid “They Relax”
innervation: RLN
6
Q
function & innervation of lateral cricoarytenoid muscle
A
function: ADDucts vocal folds (closes glottis)
- Lateral CricoArytenoid “Lets Close Airway”
innervation: RLN
7
Q
function & innervation of posterior cricoarytenoid muscle
A
function: ABducts vocal folds (opens glottis)
- Posterior CricoArytenoid “Please Come Apart”
innervation: RLN
8
Q
function & innervation of aryepiglottic muscle
A
function: closes laryngeal vestibule
innervation: RLN
9
Q
function & innervation of interarytenoid muscles (transverse & oblique)
A
function: closes posterior commissure of glottis
innervation: RLN
10
Q
laryngeal muscles that adjust length (tension) of vocal ligaments
A
- cricothyroid (elongates/tenses)
- vocalis (shortens/relaxes)
- thyroarytenoid (shortens/relaxes)
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)
12
Q
laryngeal muscles that control sphincter muscle
A
- aryepiglottic: closes laryngeal vestibule
- interarytenoid: closes posterior commissure of glottis
13
Q
extrinsic function of cricothyroid muscles
A
contraction during swallowing pulls anterior region of cricoid cartilage towards lower border of thyroid cartilage
14
Q
extrinsic laryngeal muscles
A
all end in -hyoid except digastric
15
Q
risk factors for RLN injury
A
- external pressure from ETT or LMA
- thyroid or parathyroid surgery
- neck stretching
- neoplasm
16
Q
provides sensory innervation to face
A
CN 5 (trigeminal n.)
17
Q
branches of trigeminal nerve
A
V1 - opthalmic nerve
V2 - maxillary nerve
V3 - mandibular nerve
18
Q
nerve that innervates the nares and anterior 1/3rd of nasal septum
A
anterior ethmoidal nerve (branch of V1 opthalmic nerve)
19
Q
innervates turbinates and posterior 2/3 of nasal septum
A
sphenopalatine nerve (branch of V2 maxillary nerve)
20
Q
provides sensory innervation to anterior 2/3 of tongue
A
V2 maxillary n
21
Q
provides sensory innervation to posterior 1/3 of tongue, oropharynx, vallecula, and anterior epiglottis
A
CN IX - glossopharyngeal
22
Q
afferent limb of gag reflex
A
CN IX - glossopharyngeal n.
23
Q
efferent limb of gag reflex
A
CN X - Vagus n.
24
Q
what nerve gives rise to SLN and RLN
A
CN X - vagus
25
function of internal branch of SLN
sensory innervation to posterior side of epiglottis to the level of vocal folds
26
function of external branch of SLN
motor innervation to cricothyroid muscle (tenses vocal cords)
27
symptom of acute injury to SLN trunk or external branch
hoarseness
28
function of RLN
- sensory innervation below level of vocal folds to the trachea
- motor innervation to all intrinsic laryngeal muscles except cricothyroid
29
where does the RLN branch off of CN X
- inside thorax
- right RLN: loops under subclavian artery
- left RLN: loops under aortic arch
30
what part of the RLN is most susceptible to injury and why
left RLN - due to location in thorax
31
risk factors for left RLN injury
- PDA ligation
- left atrial enlargement (from mitral stenosis)
- aortic arch aneurysm
- thoracic tumor
32
s/s acute unilateral RLN injury
- paralysis of ipsilateral vocal cord ABductors (unopposed ADDuctor action)
- hoarseness
33
s/s acute bilateral RLN injury
- bilateral paralysis of vocal cord ABductors
- unopposed tension of cricothyroid
- stridor, respiratory distress (presents similary to laryngospasm)
34
provides motor innervation to muscles of mastication
V3 - mandibular n. (branch of trigeminal n)
35
what nerve must be anesthetized to prevent pt from gagging during awake intubation
glossopharyngeal (CN IX)
36
where does the SLN branch off of the vagus n.
just beyond jugular foramen at skull base
37
where does the SLN divide into internal and external branches
at level of hyoid
38
where does the internal SLN branch penetrate thyrohyoid membrane
between greater cornu of hyoid bone and superior horn of thyroid cartilage
39
most common nerve injury folowing subtotal thyroidectomy
unilateral RLN injury
40
topical techniques to anesthetize nares
- 4% lidocaine + vasoconstrictor
- cocaine
- topical LA in eacn nare
41
risk of using viscous lidocaine to anesthetize airway
N/V
42
risk of 20% benzocaine to anesthetize airway and the treatment
methemoglobinemia
treat with methylene blue
43
which typically works better to anesthetize airway - nebulization or atomization
atomization
44
3 techniques to anesthetize vocal cords
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
45
3 nerves that must be blocked to provide complete anesthesia to airway
1. glossopharyngeal n.
2. superior laryngea n.
3. recurrent laryngeal n.
46
glossopharyngeal nerve block technique
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
47
glossopharyngeal n. block - what does aspiration of air vs. blood mean
air: needle is too deep
blood: needle should be withdrawn and redirected medially (carotid is close)
48
risk of glossopharyngeal n block
5% incidence of intracarotid injection - risk of seizure
49
SLN nerve block
- 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
50
what does air aspiration during SLN block mean
needle is too deep
51
RLN block
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
52
location of adult larynx (in relation to C spine)
anterior to C3-C6
(infant = C2-C4)
53
3 primary functions of larynx
1. airway protection
2. respiration
3. phonation
54
3 unpaired cartilages of the larynx
1. epiglottis
2. thyroid
3. cricoid
55
serves as the major structural component of the larynx
thyroid
56
how is the thyroid attached to the hyoid bone
thyrohyoid ligament
57
forms inferior border of larynx
cricoid
58
entry point for surgical airway
cricothyroid membrane
59
only complete cartilaginous ring in the airway
cricoid
60
3 paired cartilages of the larynx
1. arytenoids
2. corniculates
3. cuneiforms
61
serve as posterior attachment of vocal cords
arytenoids
62
only bone in the body that does not articulate with another bone
hyoid bone
63
why might patients with lupus or RA have increased risk of airway obstruction
impaired arytenoid mobility
64
forms main support of larynx
hyoid bone
65
attaches larynx (via thyroid cartilage) to hyoid bone
thyrohyoid ligament
66
attaches cricoid and thyroid cartilages
cricothyroid membrane
67
provides mechanical barrier between pharynx and laryngeal opening
epiglottis
68
connects epiglottis to thyroid cartilage
thyroepiglottic ligament
69
base articulates with cricoid cartilage to form a ball and socket joint
arytenoids
70
provide structure to aryepiglottic folds
corniculate & cuneiform cartilages
71
T/F - you can see arytenoids during DL
false
72
narrowest region of the airway in adults vs. kids
adults - glottic opening
kids (5 and under) - narrowest fixed region is cricoid ring; narrowest dynamic region is vocal cords
73
swelling of what region causes post-extubation laryngeal edema in children
swelling around cricoid cartilage
74
what is a laryngospasm?
sustained and involuntary contraction of laryngeal musculature that results in inability to ventilate
75
complications of laryngospasm
- airway obstruction
- NPPE
- aspiration
- Dysrhythmias
- cardiac arrest
76
s/s laryngospasm
- stridor
- suprasternal & supraclavicular retraction with inspiration
- "rocking horse" breathing
- increased diaphragmatic excursion
- lower rib flailing
- absent/altered EtCO2 waveform
77
pre-anesthetic risk factors for laryngospasm
- active URI
- URI within past 2 weeks
- 2nd hand smoke exposure
- reactive airway
- GERD
- age < 1 year
78
intraop risk factors for laryngospasm
- 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
duration of laryngeal lidocaine
~30 minutes
80
treatment of laryngospasm
- 100% FiO2
- remove noxious stim
- deepen anesthesia (volatile, propofol, lidocaine)
- CPAP 15-20 cm H2O
- head extension, chin lift, Larson's
- succs
81
dosing of succs for laryngospasm
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
site of fastest onset of IM succs
submental
83
only NMBs that can be given IM
- succs
- roc
84
what med shold be co-administered with succs in kids < 5 yrs old
atropine 0.02 mg/kg to prevent bradycardia
85
what is Larson's maneuver?
what does it accomplish?
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
how to apply Larson's maneuver
apply pressure for 3-5 seconds then release for 5-10 seconds
repeat until laryngospasm breaks
87
what is valsalva's maneuver? what are the risks?
- exhalation against a closed glottis (obstruction)
- ex: coughing, bucking, bearing down
- risk: increased pressure in thorax, abdomen, brain
88
Muller's maneuver and risks
- inhalation against closed glottis (obstruction)
- ex: patient bites down on ETT and takes deep breath
- risk: subatmospheric pressure in thorax, NPPE
89
3 places the upper airway can obstruct during anesthesia
- soft palate
- tongue
- epiglottis
90
relaxation of the tensor palatine muscle can cause obstruction in which part of the airway?
soft palate
91
relaxation of the genioglossus muscle can cause obstruction in which part of the airway?
tongue
92
relaxation of the hyoid muscles can cause obstruction in which part of the airway?
epiglottis
93
why should the bevel be towards the turbinates with nasal instrumentation (ex. nasal airway)
ensures leading edge travels along septum, where it's less likely to traumatize turbinates
94
why do patients in respiratory failure convert to mouth breathing?
scroll-like shape of nasal turbinates = high degree of airway resistance
95
Methods to remedy obstruction related to genioglossus muscle relaxation
- jaw thrust
- oral airway
96
what connects the oral and nasal cavities with larynx and esophagus
pharynx
97
contraction of which muscles helps to maintain airway patency
pharyngeal dilators
98
method to alleviate airway obstruction caused by relaxation of pharyngeal dilator muscles
chin lift with a closed mouth
99
where are the adenoid tonsils located
superior and posterior walls of nasopharynx
100
how can lingual tonsils affect airway DL and airway placement
hypertrophy can hinder DL or impair seating of supraglottig airway device
101
what all is included in the upper airway
mouth and nares to cricoid cartilage
102
3 primary functions of the upper airway
1. warming & humidifying inspired air
2. filtering particulate matter
3. preventing aspiration
103
3 sets of dilator muscles that counteract tendency for airway collapse in awake patients
1. tensor palatine
2. genioglossus
3. hyoid muscles
104
function of tensor palatine muscle
opens nasopharynx
105
function of genioglossus muscle
opens oropharynx
106
function of hyoid muscles
opens hypopharynx
107
where does the trachea begin and end
- begins at inferior border of cricoid cartilage
- teminates at carina (~T4-T5)
108
what are the bifurcations off of the carina?
right and left mainstem bronchi
109
why is endobronchial intubation more likely to occur on the right side?
less acute angle (25 deg)
110
Why do right sided DLTs require meticulous positioning?
The takeoff to RUL is only 2.5 cm from the carina
111
where does the lower airway begin and end
- begins at trachea
- ends at alveoli
112
what vertebral level corresponds with the adult trachea
C6
113
allows air movement between alveoli
pores of Kahn
114
sensory innervation of the trachea
vagus n.
115
blood supply to the trachea
- inferior thyroid artery
- superior thyroid artery
- bronchial artery
- internal thoracic artery
116
what part of the airway corresponds with the angle of Louis
carina
117
type of cells in the trachea
ciliated columnar epithelium
118
type of cells in the alveoli
squamous epithelium
119
type of cells in carina
ciliated columnar epithelium
120
function of type 1 pneumocytes
provide surface for gas exchange
121
type of cells that cover ~80% of alveolar surface
type 1 pneumocytes
122
what type of pneumocytes are resistant to oxygen toxicity
type II
123
what type of pneumocytes are macrophages
type III
124
when are neutrophils present in the alveoli?
- smokers
- acute lung injury
125
how long is the right vs. left mainstem bronchi
right: 2.5 cm long
left: 5 cm long
126
function of type 3 pneumocytes
- fight lung infection
- produce inflammatory response
127
how wide is the trachea
2.5 cm
128
distance from incisors to larynx
~13 cm
129
distance from larynx to carina
~13 cm
130
distance from incisors to carina
~26 cm
131
what explains why neck positioning can cause endobronchial intubation or inadvertent extubation
neck flexion makes distance from incisors to carina shorter, extension makes the distance longer
132
degree of R and L mainstem bronchi in children < 3 yrs
both take off 55 degrees from long axis of trachea
133
what happens to # airways and total cross sectional area as airway bifurcates
increase
134
4 things that decrease as airway bifurcates
- airflow velocity
- amount of cartilage
- goblet cells
- ciliated cells
135
function of goblet cells
produce mucus
136
function of ciliated cells
clear mucus
137
what type of pneumocyte produces surfactant?
type 2
138
what 2 landmarks correspond with the carina
T4-5
angle of louis
139
solely responsible for opening vocal cords
posterior cricoarytenoid
140
most common cause of RLN injury
thyroid surgery
141
most caudal cartilage in larynx
cricoid
142
most common cause of RLN injury
thyroid surgery
143
layngeal cartilages most superior to most inferior
epiglottis
corniculate
arytenoid
cricoid
144
afferent limb of laryngospasm
SLN internal branch
145
efferent limb of laryngospasm
external SLN, RLN
146
adult trachea length
10-13 cm
147
landmarks for larson's maneuver
posterior = mastoid process
superior = skull base
anterior = ramus of mandible
148
function of muscle in pink
elongates (tenses) vocal cords
| cricothyroid
149
function of muscle in green
shortens/relaxes vocal cords
adducts vocal folds (closes glottis)
| thyroarytenoid
150
function of muscle in blue
ADDucts vocal folds (closes glottis)
| lateral cricoarytenoid
151
function of muscle in orange
ABducts vocal folds (opens glottis)
| posterior cricoarytenoid
152
function of muscle in purple
shortens (relaxes) vocal cords
| vocalis
