Airway Anatomy Flashcards
Muscles that tense the vocal cords?
elongates
Cricothyroid
(“cords tense”)
think of the cricothyroid as the tuning fork for the vocal cords :)
Muscles that relax the vocal cords?
Thyroarytenoids
“They Relax”
Muscles that ABduct the vocal cords?
Posterior Cricoarytenoid
“pull cords apart”
Muscles that ADduct the vocal cords?
Lateral Cricoarytenoids
“let’s close airway”
The superior laryngeal nerve branches off what nerve?
Vagus nerve
The superior laryngeal nerve divides into what two branches?
internal and external branch of the SLN.
The internal branch of the SLN penetrates what membrane?
The internal branch penetrates the thyrohyoid membrane.
The external branch of the SLN enters which muscle?
The external branch enters the cricothyroid muscle.
The RLN branches off of the vagus nerve inside of what structure?
inside the thorax
What does the right RLN loop under and what does the L RNL loop under?
The right RLN loops under the subclavian artery.
The left RNL loops under the aortic arch.
Which RLN is more susceptible to injury?
The left due to looping under the aortic arch.
Which branch of the SLN innervates the cricothyroid muscle?
external branch (motor)
Which nerve innervates the posterior side of the epiglottis to the top side of the vocal cords?
SLN internal branch
Which nerve innervates the cricothyroid muscle?
SLN external branch
4 nerves that innervate the sensory portion of the airway?
trigeminal
glossopharyngeal
SLN
RLN
Injury to the trunk of the SLN or the external branch can cause what and why?
can cause hoarseness, because the vocal cords can not tense.
Unilateral injury to the RLN results in what kind of paralysis? Does it cause Respiratory distress?
results in paralysis of the ipsilateral vocal cord abductors, this does not cause respiratory distress.
Explain acute bilateral injury to the RLN and what must be done?
Results in bilateral paralysis of the vocal cord abductors. This allows for unopposed tensing action by the cricothyroid muscle. Therefore a patient with an acute injury to BOTH RLNs is at risk for stridor and respiratory distress.
Patient requires intubation or surgical airway.
Chronic injury to the RLN, tell me about it?
well tolerated and does not cause respiratory distress.
What are some conditions that can cause Left side only RLN injury?
Aortic arch aneurysm
Thoracic tumor
Left atrial enlargement (mitral stenosis)
PDA ligation
Glossopharyngeal Block, how to tell when you are too deep, when to redirect, how much LA is injected, and what are the risks?
aspiration of air = too deep
when you aspirate blood you should withdrawal and redirect medially.
1-2ml of LA on both sides injected
5% incidence of intracarotid injection with a risk of seizures
Where do you inject for a glossopharyngeal block?
needle is inserted at the base of the palatoglossal arch (anterior tonsillar pillar) depth of 0.25-0.5 cm.
Insertion direction of the needle during a transtracheal block?
needle is advanced in a caudal direction as it penetrates the cricothyroid membrane.
During a transtracheal block what should the patient do before injection of LA, and what does this cause?
After aspiration and before injection the patient should take a deep breath, during the deep breath 3-5ml of LA is injected to the tracheal lumen this causes the patient to cough and sprays LA up through the cords.
The adult larynx extends from what vertebrae to what vertebrae?
C3-C6
name the three paired cartilages and the three unpaired cartilages
Paired are : corniculate
arytenoid
cuneiform
unpaired are:
Thyroid
cricoid
Epiglottis
Can you see the arytenoids during direct laryngoscopy?
No
What two diseases can significantly decrease the movement of the arytenoids and possibly cause airway obstruction?
rheumatoid arthritis and Lupus
the arytenoids create a ball and socket joint with the cricoid cartilage allowing the vocal cords to move and function
What membrane is punctured during a cricothyroidotomy for emergent securement of the airway?
cricothyroid membrane
know the location for a hotspot question, below the thyroid and above the cricoid
What is the largest cartilage in the larynx?
Thyroid
What is the the only complete cartilaginous ring in the airway?
Cricoid
What is the narrowest part of the pediatric airway? (controversial answer)
The answer will be either vocal cords or cricoid ring.
In the anesthetized child the narrowest region is the vocal cords BUT they are soft and can be stretched by an ETT placed between them.
The cricoid ring is fixed and can not be stretched or increased in diameter, it can however be reduced by edema that results from an ETT that is too large, multiple intubations, prolonged intubation etc.
So hopefully both will not be listed on boards as an answer and if they are maybe the question will clue you in.
Narrowest region in the adult airway?
vocal cords
If a patient has a laryngospasm what outcomes may it result in?
complete airway obstruction negative pulmonary edema gastric aspiration cardiac arrest death
Risk factors for laryngospasm previous to anesthesia?
active or recent upper airway infection (<2 weeks)
exposure to 2nd hand smoke
reactive airway disease
GERD
age less than 1 year
Risk factor for laryngospasm in the OR?
light anesthesia concurrent with airway manipulation
saliva or blood in the upper airway
hyperventilation
hypocapnia
surgical procedures involving the airway
Reflex pathway: what is the afferent limb?
SLN internal branch
Reflex pathway: what is the efferent limb?
SLN external branch + recurrent laryngeal nerve
ADDuction of the vocal cords is by?
lateral cricoarytenoid and thyroarytenoid
Tensing of the vocal cords is by?
cricothyroid
Signs of a laryngospasm?
inspiratory stridor
suprasternal and supraclavicular retraction during inspiration
“rocking horse” appearance of chest wall
increased diaphragmatic excursion
lower rib flailing
factors that reduce the likelihood of laryngospasm?
avoidance of airway manipulation during light plane
CPAP 5-10 during inhalation induction as well as immediate post extubation
removal of pharyngeal secretions and blood before extubation.
deep or awake extubation, not in between
Laryngeal lidocaine (only last 30 min.)
IV lidocaine before extubation
hypercapnia/hypoventilation
PaO2 < 50 mmHg
What natural mechanism tends to break laryngospasm? (but you do not want to wait around for it)
hypercapnia and hypoxemia
If a child is less than five years of age you should administer what with your succinylcholine and why?
atropine 0.02 mg/kg with succinylcholine to prevent bradycardia
What is/how do you perform Larson’s Maneuver?
It is not a simple jaw thrust.
Larson’s maneuver is application of firm pressure to the laryngospasm notch located just behind the earlobe. Pressure is applied bilaterally towards the skull base.
pressure should be applied for 3-5 seconds then released for 5-10 seconds. Repeat until relief of laryngospasm
What does Larson’s maneuver accomplish?
- displaces the mandible anteriorly to help open the airway.
- it often breaks laryngospasm by causing the lightly anesthetized patient to sigh.
What is the difference between Valsalva’s maneuver and Muller’s maneuver?
Valsalva is exhalation against a closed glottis
Muller’s is inhalation against a closed glottis
The risk of Muller’s is sub atmospheric pressure in the thorax that can cause negative pressure pulmonary edema
During anesthesia relaxation of the Tensor Palatine muscle will most likely cause airway obstruction at which level?
soft palate
During anesthesia relaxation of the Genioglossus muscle will most likely cause airway obstruction at which level?
Tongue
During anesthesia relaxation of the hyoid muscle will most likely cause airway obstruction at which level?
Epiglottis
Where does the lower airway begin and end?
Begins at the trachea and ends at the alveoli.
The trachea begins at what vertebrae and ends at what vertebrae?
begins at C6 and ends at T4-5
Sensory innervation of the trachea is by what nerve?
Vagus
The carina is at located at what vertebrae?
T4-5
The R mainstem bronchi has an angel of?
25 degrees
The L mainstem bronchi has an angle of?
45 degrees
How long is the R mainstem bronchi and the L mainstem bronchi?
R is 2.5 cm long
L is 5 cm long
Which type of cells in the lungs produce surfactant?
Type II cells
Which type of cells in the lungs provide surface for gas exchange?
Type I cells
Which type of cells in the lungs can produce another type of cells in the lungs?
type II cells can produce type I cells
Which cell type in the lungs is resistant to oxygen toxicity and capable of cell division?
Type II cells
Which cell type in the lungs are macrophages?
Type III cells
Which cell type in the lungs cover 80% of alveolar surface and form tight junctions?
Type I cells
Which cell type in the lungs fights infection and produces inflammatory response?
Type III cells
True or False
Neutrophils are present in all normal lungs alveoli?
False, neutrophils are present in the alveoli in smokers and patients with acute lung injury.
What is the distance between the incisors and the larynx and then the distance from the larynx to the carina?
13 cm and 13cm for a total of 26 cm (variability can exist)
What is different about the take off degree of the mainstem bronchi in children up to 3 years of age?
both bronchi take off at 55 degrees
Does airflow velocity speed up or slow down as you move down the tracheobronchial tree?
slows down
This is because at each division the diameter of the the new branches become smaller, however the total cross sectional area of all the airways in the division increases.
What two things does the trachea contain that the terminal bronchioles do not have?
C shaped rings goblet cells (mucus secretion)
The anterior tongue (2/3) is innervated by which nerve?
Trigeminal nerve
The vallecula is innervated by which nerve?
Glossopharyngeal
The Trachea is innervated by which nerve?
RLN
The posterior epiglottis is innervated by which nerve?
SLN
What three nerve blocks provide anesthesia for oral fiberoptic intubation?
glossopharyngeal, superior laryngeal, and recurrent laryngeal blocks.
What block would you perform for a patient to tolerate a scope in the oropharynx?
glossopharyngeal block which is 1-2ml of LA at the tonsillar pillars bilaterally.
If a patient can not tolerate a scope for awake intubation just beyond the epiglottis but before the vocal cords then what regional technique will increase the patients ability to tolerate the rest of the procedure?
3 ml at the inferior aspect of the greater cornu of the hyoid bone bilaterally. (SLN nerve block)
The infant larynx is located?
C2-C4
Tensor palatine dilator muscle opens the
a. oropharynx
b. nasopharynx
c. hypopharynx
b. nasopharynx
Genioglossus dilator muscle opens the
a. oropharynx
b. nasopharynx
c. hypopharynx
a. oropharynx
hyoid dilator muscles open the
a. oropharynx
b. nasopharynx
c. hypopharynx
c. hypopharynx
What are the three landmarks for Larson’s maneuver?
Mastoid process
skull base
Ramus of mandible
Lung cells are called pneumocytes, which type of pneumocytes are present where gas exchange occurs?
Type I
