Airway anatomy Flashcards
The laryngeal muscles are classified as
intrinsic or extrinsic
The intrinsic laryngeal muscles control
the tension and position of the vocal cords
involved in phonation
What is the function of the cricothyroid?
“Cords tense”
What is the function of the thyroarytenoid?
“They relax”
What is the function of the posterior cricoarytenoid?
ABducts vocal cords
“Please come apart”
What is the function of the lateral cricoarytenoid?
ADDucts vocal cords
“let’s close airway”
The ____________ innervates all of the intrinsic laryngeal muscles except for the cricothyroid muscle, which is innervated by the _______________
recurrent laryngeal nerve; external branch of the superior laryngeal nerve
The ____________ is solely responsible for opening the vocal cords.
posterior cricoarytenoid
The ______ support the larynx inside the neck and assist with swallowing
extrinsic laryngeal muscles
All the extrinsic muscles end in
“-hyoid”
What is the only extrinsic muscle that doesn’t end in “-hyoid”
digastric
Muscles that depress the larynx include
thyrohyoid
omohyoid
sternohyoid
all other extrinsic muscles elevate the larynx
The superior laryngeal nerve innervates the:
a. cricothyroid muscle
b. trachea
c. posterior third of the tongue
d. underside of the epiglottis
a. cricothyroid muscle
d. underside of the epiglottis
The internal branch of the superior laryngeal nerve is a
sensory nerve
The external branch of the superior laryngeal nerve is a
motor nerve
The ______ provides sensory innervation to the face and head
trigeminal nerve (CN 5)
The CN 5 is divided into three branches
V1 (ophthalmic)
V2 (maxillary)
V3 (mandibular)
The V1 or ophthalmic nerve innervates the
nares and anterior 1/3rd of the nasal septum
The V2 or maxillary nerve innervates the
turbinates and nasal septum
The V3 or mandibular nerve innervates the
anterior 2/3rd of tongue (somatic)
The ______ provides sensation from the oropharynx down to the anterior side of the epiglottis
glossopharyngeal nerve (CN9)
The ________ gives rise to the superior laryngeal nerve
Vagus nerve (CN10)
The superior laryngeal nerve is divided into
the internal branch
external branch
The __________ gives rise to the recurrent laryngeal nerve which provides sensation below the level of the vocal cords
vagus nerve
The recurrent laryngeal nerve innervates the _______
posterior cricoartyenoid muscle
When the recurrent laryngeal nerve is paralyzed
unilateral injury–> no respiratory distress
bilateral injury (acute)–> respiratory distress
bilateral injury (chronic)–> no respiratory distress
Risk factors for recurrent laryngeal nerve injury include
PDA ligation, left atrial enlargement (mitral stenosis), aortic arch aneurysm, and thoracic tumor
If the superior laryngeal nerve is injuryed
bilateral injury can cause hoarseness
Which recurrent laryngeal nerve is more susceptible to injury?
left RLN
If the patient gags during fiberoptic intubation, then this nerve was not adequately anesthetized:
glossopharyngeal nerve
The sensory function of the recurrent laryngeal nerve is at
below level of the vocal cords–> trachea
The internal branch of the superior laryngeal nerve penetrates the
thyrohyoid membrane between the greater cornu of the hyoid bone and the superior horn of the thyroid cartilage
The external branch of the superior laryngeal nerve penetrates the
cricothyroid muscle
RLN injury that can affect either side includes
external pressure from ETT/LMA
surgery: Thyroid/parathyroid
neck stretching
neck tumor
RLN injury that affects the left side only
PDA ligation
left atrial enlargement (mitral stenosis)
aortic arch aneurysm
thoracic tumor
The most common nerve injury following subtotal thyroidectomy is
unilateral RLN injury
Treatment for bilateral RLN injury is
emergent intubation or a surgical airway
The ___________ has no motor function
The superior laryngeal internal branch
The _______ provides sensation below the level of the vocal cords to the trachea
RLN
The ___________ has no sensory function
SLN external branch
The ____________ has sensation to the posterior side of the epiglottis to vocal cords
SLN internal branch
he ________ has motor function to the cricothyroid muscles
SLN external branch
The ___________ has motor function to all intrinsic laryngeal muscles except the cricothyroid
RLN
Which landmark is identified for a superior laryngeal nerve block?
a. greater cornu of hyoid bone
b. superior horn of thyroid cartilage
c. cricothyroid membrane
d. palatoglossal arch
a. greater cornu of hyoid bone
