Airway Anatomy Flashcards
Laryngeal muscles are classified as ______ or _______
intrinsic or extrinsic
Intrinsic laryngeal muscles participate in?
Phonation and control of the vocal cords (tensions and position)
Extrinsic Laryngeal muscles participate in?
Support the larynx inside the neck and assist with swallowing
True or False: The true vocal cords are ligaments and are, therefore, not innervated.
True
What do the true vocal cords attach to?
Attach to the thyroid cartilage anteriorly and the arytenoids posteriorly.
What muscles adjust the length or tension of the vocal ligaments? Either tense and relax.
Cricothyroid = elongates (tenses)
Vocalis = shortens (relaxes)
Thyroarytenoid = shortens (relaxes)
Function and Innvervation of the Cricothyroid Muscle
Intrinsic Laryngeal muscle. Elongates (tenses) vocal cords. [Does have an extrinsic function. During swallowing, pulls anterior region of cricoid cartilage down]
Innervated by External Superior Laryngeal Nerve
Function and Innvervation of the Vocalis Muscle
Intrinsic Laryngeal muscle. Shortens (relaxes) vocal cords.
Innervated by the Recurrent Laryngeal Nerve
Function and Innvervation of the Thyroarytenoid Muscle
Intrinsic Laryngeal muscle.
Shortens (relaxes) vocal cords.
Adducts vocal folds (closes glottis)
Innervated by the Recurrent Laryngeal Nerve
All intrinsic laryngeal muscles are innervated by _________ except ________ muscles
all innervated by the recurrent laryngeal nerve except the cricothyroid muscles
What intrinsic laryngeal muscles adduct or abduct the vocal folds (glottic diameter)
Thyroartytenoid (aDducts)
Lateral cricoarytenoid (aDducts, Lets Close)
Posterior cricoarytenoid (aBducts, Please Come Apart)
Function and Innvervation of the Lateral Cricoarytenoid
ADDucts the vocal folds (narrows glottis)
Recurrent Laryngeal Nerve
Function and Innvervation of the Posterior Cricoarytenoid
ABducts the vocal folds (widens glottis)
Recurrent Laryngeal Nerve
Function and Innvervation of the Aryepiglottic muscle
Closes laryngeal vestibule
Recurrent Laryngeal Nerve
Function and Innvervation of the Interarytenoid muscle
Closes posterior commissure of glottis
Recurrent Laryngeal Nerve
Name the extrinsic laryngeal muscles the depress the larynx
Omohyoid
Sternohyoid
Sternothyroid
Name the extrinsic laryngeal muscles the elevate the larynx
Digastric (ant and posterior belly)
Mylohyoid
Stylohyoid
Thyrohyoid
What 3 cranial nerves innervate the upper airway?
Trigeminal - CN 5
-V1: opthalamic, V2: maxillary, and V3: mandibular
Glossopharyngeal CN 9
Vagus CN 10
V3: The mandibular branch of the trigeminal provides motor innervation to?
Muscles of mastication
What cranial nerve provides motor innervation to the tongue?
CN 12 - Hypoglossal
CN 9 - Glossopharyngeal relays sensation information from what areas in the upper airway?
Soft Palate
Oropharynx
Tonsils
Posterior 1/3 of Tongue
Vallecula
Anterior side of epiglottis
Afferent limb of gag reflex
If the patient gags during intubation, what nerve sensed that stimulation
Glossopharyngeal CN 9
The Glossopharyngeal CN 9 participates in what two motor functions
Participates in swallowing and phonation
Trigeminal V1: Ophthalmic nerve has what sensory function
Nares and Anterior 1/3 of nasal septum
Trigeminal V2: Maxillary (sphenopalatine) nerve has what sensory function
Turbinates and septum
Trigeminal V3: Mandibular nerve has what sensory function? What motor function?
Sensation: Anterior 2/3 of tongue
Motor: Mastication
The Vagus Nerve - CN 10, divides into what branches.
Superior Laryngeal Nerve
-internal
-external
Recurrent Laryngeal Nerve
What are the sensory and motor functions of the Internal branch of the Superior Laryngeal Nerve
Motor: NO MOTOR
Sensory: Posterior side of epiglottis to the level of the vocal cords
What are the sensory and motor functions of the External branch of the Superior Laryngeal Nerve
Motor: Cricothyroid muscles (tense vocal cords)
Sensory: No Sensory
What are the Sensory and Motor functions of the Recurrent Laryngeal Nerve?
Motor: ALL intrinsic laryngeal muscles Except Cricothyroids
Sensory: Below the level of vocal cords to the trachea
At the level of the ______, the Superior Laryngeal Nerve branches into the internal and external.
Hyoid
The internal branch of the superior laryngeal nerve penetrates what membrane?
Thyrohyoid Membrane
The External Branch of the Superior Laryngeal Nerve innervates?
Cricothyroid Muscle
Where do the recurrent laryngeal nerves branch off the vagus nerve?
Inside the thorax
The Right Recurrent Laryngeal Nerve loops under what structure to reach the larynx
Loops under the right subclavian artery
The Left Recurrent Laryngeal Nerve loops under what structure to reach the larynx
Loops under the aortic arch
Which recurrent laryngeal nerve is more susceptible to injury? Why?
Due to its position under the aortic arch, the left RLN is more likely to be injured
Bilateral recurrent laryngeal nerve injury can be caused by?
External pressure from ETT / LMA
Surgery: thyroid/parathyroid
Neck stretching
Neck tumor
Left recurrent laryngeal nerve injury can be caused by?
PDA ligation
Left Atrial Enlargement (mitral stenosis)
Aortic Arch dissection
Thoracic tumor
The trachea is approximately how long in adults?
~10-20 cm
The Cricothyroid muscle is innervated by?
External Branch of the Superior Laryngeal Nerve
In preperation for an awake intubation, you anesthetize the upper airway with aerosolized lidocaine. Shortly after you begin the procedure, the patient is unable to tolerate the scope just beyond the epiglottis but before the vocal cords. Which regional technique will increase the patients ability to tolerate the rest of the procedure?
- 2mL at the tonsillar pillars
- 3 mL at the inferior aspect of the greater cornu of the hyoid bone
- 4mL at the thyroepiglottic membrane
- 5mL at the cricothyroid membrane
3mL at the inferior aspect of the greater cornu of the hyoid bone bilaterally.
Pt tolerated the scope in the oropharynx, which is innervated by the glossopharyngeal nerve. Once the scope entered the territory covered by the Superior Laryngeal Branch, the pt was uncomfortable. (Superior Laryngeal Block 3mL at the inferior aspect of the greater cornu of hyoid)
Which of the following is MOST likely to injure the Left Recurrent Laryngeal Nerve while sparing the RLN?
1. Mitral Stenosis
2. External pressure from a LMA
3. External pressure from an ETT
4. Parathyroidectomy
Mitral Stenosis
(The left RLN loops under the aorta, making it more susceptible to injury. May present with hoarseness)
The adult larynx is located? The infant larynx is located?
Adult: C3-C6
Infant: C2-C4
What muscle abducts the vocal cords?
Posterior Cricoartytenoid
The Larynx consists of ____ cartilages. ___ paired and ____ unpaired. What are they?
9 cartilages
3 Paired, 3 Unpaired
Paired: Corniculate, Arytenoid, and Cuneiform
Unpaired: Epiglottis, Thyroid, Cricoid
For a patient in sitting position, order the cartilages from superior to inferior: cricoid, corniculate, arytenoid, and epiglottis
Epiglottis
Corniculate
Arytenoid
Cricoid
What are the functions of the upper airway dilator muscles? Tensor Palatine, Hyoid Muscles, Genioglossus
Tensor Palatine - opens nasopharynx
Hyoid Muscles - opens hypopharynx
Genioglossus - opens oropharynx
Which type of pneumocyte produces surfactant?
Type 2: produce surfactant and can divide to produce type 1 cells
What are some risk factors for laryngospasm?
GERD
Exposure to secondhand smoke
recent URI
Light anesthesia
HyPOcapnia
Saliva or Blood in athe irway
Age < 1
All of the following are landmarks for the Larson’s Manuever EXCEPT?
1. mastoid process
2. skull base
3. mandibular body
4. ramus of mandible
Mandibular body
Match the Nerve to the Structure that is innervates:
Nerve: Trigeminal, Superior Laryngeal, Glossopharyngeal, Recurrent Laryngeal
Structures: Anterior tongue, Vallecula, Posterior Epiglottis, Trachea
Trigeminal - Anterior Tongue
Superior Laryngeal - Posterior Epiglottis
Recurrent Laryngeal - Trachea
Glossopharyngeal - Vallecula
