Apex- Airway Anatomy Flashcards
Match the intrinsic muscle of the larynx with its action on the vocal cords
Thyroidarytenoid
Lateral cricoarytenoid
Cricothyroid
Posterior cricoarytenoid
Shortens
Elongates
Abducts
Adducts
Thyroidarytenoid
>Shortens “THey Relax”
Lateral Cricoarytenoid
>Adducts “Leaves Cords Alone”
Cricothyroid
>elongates “Cords Tense”
Posterior cricoarytenoid
>Abducts “Pulls Cords Apart”
The RLN innervates all of the intrinsic laryngeal muscles except what?
What is that innervated by?
The cricothyroid muscle
- the external branch of the SLN
All laryngeal muscles are classified as intrinsic or extrnisic, which are each responsible for?
Intrinsic- phonation (tension and position of cords)
Extrnsic- support the larynx and assist with swallowing
The vocal cords attach to the __________anteriorly, and the _________posteriorly.
thyroid anteriorly
arytenoids posteriorly
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What does the vocalis do?
Shorten (relaxes) the vocal cords
Which laryngeal muscle has 2 functions and what are they?
Thyroarytenoid
- THey Relax > shortens (relaxes) VCs
- ADDucts (in ADDition to relaxing, they adduct the VCs) [close the glottis]
What kind of muscles end in “-hyoid?”
Extrinsic muscles of the larynx
*Except digastiric
What muscles tense/relax the vocal cords?
Tense = CricoThyroid “Cords Tense”
Relax = THyro aREtenoid “THey RElax”
Which muscles Abduct vs Adduct the vocal cords?
Abduct = Posterior CricoAretynoids “Pulls Cords Apart”
Adduct = Lateral CricoAretynoids “Leaves Cords Alone”
The SLN innervates (select 2):
- Cricothyroid muscle
- Trachea
- Posterior third of the tongue
- Underside of the epiglottis
- Cricothyroid
- Underside of the epiglottis
What 4 nerves innervate the airway?
- Trigeminal (CNV)
- Glossopharyngeal (CNIX)
- SLN (internal and external)
- RLN
What does the internal vs external branches of the SLN innervate?
internal branch = sensory
posterior side of epiglottis > top of the vocal cords
NO MOTOR
external branch = motor
cricothyroid muscle
NO SENSORY
CN9 (GP) provides sensation from where to where
oropharynx down to the anterior side of the epiglottis
What gives rise to the SLN?
Vagus (X)
Trigeminal subsets and function:
V1:
V2:
V3:
V1: (opthalmic): SENSORY to nares and anterior 1/3 nasal septum
V2: (Maxillary): SENSORY to turbinates and nasal septum; anterior 2/3 tongue - sensory
V3: (Mandibular): muscles of mastication MOTOR
What gives rise to the RLN and what does the RLN provide sensation to if anything?
Vagus nerve gives rise to RLN
sensation BELOW the elvel of the cords > trachea
Most common cause of RLN injury (either side) and 3 other potential causes
*Thyroidectomy* (neck surgery)
- overinflation of ETT or LMA cuff
- tumor
- excessive neck stretching
What 4 things can cause injury to the LEFT RLN?
- PDA ligation
- Left atrial enlargement (Mitral stenosis)
- aortic arch aneurysm
- Thoracic tumor
What closes the laryngeal vestibule?
Aryepiglottic fold? sphincter?
What closes the posterior commisure of the glottis?
Interarytenoid
(RLN)
Which extrinsic muscles depress the larynx? (3)
SOS
Stern oyhoid
Omohyoid
_Stern_othyroid
(all other extrinsic muscles “-hyoid” elevate the larynx + the digastric)
What kind of nerve damage would result in one of the vocal cords being unable to abduct?
RLN damage
T/F: injury to b/l SLN’s constitutes a respiratory emergency
FALSE
- B/L RLN -neither cord can abduct
- stridor/resp distress
Laryngospasm is a forceful, involuntary spasm of the laryngeal muscles caused by stimulation of what nerve?
the INTERNAL branh of the SLN
Sensory vs motor innervation for a laryngospasm
Sensory (afferent) innervation = internal branch of the SLN
Motor (efferent) innervation = external branch of the SLN (cricothyroid, cords tense)
AND RLN (Lat. cricoaretenoids & thyroaretynoids = adduct cords)
Hoarseness would be injury to SLN or RLN
RLN
-hoaRness
(SLN = Softness)
What 3 cranial nerves are responsible for innervation of the airway?
- Trigeminal nerve (V)
- Glossopharyngeal (IX)
- Vagus (X)
>SLN, RLN
Trigeminal V1, V2, V3 matching:
Lingual nerve
Anterior ethmoidal nerve
Sphenopalantine nerve
V1 = anterior ethmoidal
V2 = sphenopalantine
V3 = lingual nerve
What serves as the afferent nerve of the gag reflex
efferent nerve?
CN IX - glossopharyngeal (Sensory = affernt)
X = efferent limb/motor resposne of gagging
What provides motor innervation to the muscles of mastication (chewing)
V3 division of CNV
)
What provides motor inneration to the tongue?
CN 12 - hypoglossal nerve
CN 9 (GP) provides sensory innervation from the oropharynx to the anterior side of the epiglottis. What 6 structures are included?
- Soft palate
- Oropharynx
- Tonsils
- Posterior 1/3 of tongue
- Vallecula
6. Anterior side of the epiglottis
CN 5 is mostly sensory, what is the exception?
Muscles of mastication innervated by V3 Mandibular/linguial nerve
(sensory of this is anterior 2/3 of tongue)