Airway Innveration + Blocks

Question 1

What is the function of the Facial nerve (VII)?

Answer 1

Motor to facial muscles.

Question 2

What is the function of the Trigeminal nerve (V)?

Answer 2

Sensory to face, nasal cavity, palate; motor to mastication.

Question 3

What is the function of the Glossopharyngeal nerve (IX)?

Answer 3

Gag reflex; sensory to posterior tongue and pharynx.

Question 4

What is the function of the Vagus nerve (X)?

Answer 4

Includes SLN and RLN; controls vocal cords, airway reflexes.

Question 5

What does the internal branch of the Superior Laryngeal Nerve (SLN) do?

Answer 5

Sensory above cords.

Question 6

What does the external branch of the Superior Laryngeal Nerve (SLN) do?

Answer 6

Motor to cricothyroid (affects pitch).

Question 7

What is the function of the Recurrent Laryngeal Nerve (RLN)?

Answer 7

Motor to intrinsic larynx muscles (except cricothyroid); sensory below cords.

Injury → hoarseness or stridor.

Question 8

What is the Recurrent Laryngeal Nerve (RLN)?

Answer 8

The RLN ascends from the vagus up the distal trachea, passing through the cricothyroid ligament into the proximal trachea and vocal cords.

Question 9

Where does the RLN lie?

Answer 9

The RLN lies between the trachea and esophagus.

Question 10

What is the motor function of the RLN?

Answer 10

The RLN is motor to all intrinsic laryngeal muscles except the cricothyroid.

Question 11

What does a transtracheal block anesthetize?

Answer 11

A transtracheal block anesthetizes RLN sensory fibers below the cords.

Question 12

What areas does the RLN provide sensory innervation to?

Answer 12

The RLN provides sensory innervation to the trachea, larynx below vocal cords, and the inferior surface of the epiglottis.

Question 13

What airway reflexes are affected by the RLN?

Answer 13

The RLN affects vocal cord closure and sensory function up to the inferior aspect of the epiglottis.

Question 14

What can epiglottic stimulation cause?

Answer 14

Epiglottic stimulation may cause bradycardia, bronchospasm, and hypotension via vagal reflex.

Question 15

What is a clinical consideration during intubation related to the RLN?

Answer 15

Careful handling of the RLN is required during intubation, especially in pediatrics and patients with vagal hypersensitivity.

Question 16

What is the function of the cricothyroid muscle?

Answer 16

The cricothyroid muscle is innervated by the superior laryngeal nerve and tenses and elongates the vocal cords.

Question 17

What is the function of the thyroarytenoid muscle?

Answer 17

The thyroarytenoid muscle is innervated by the recurrent laryngeal nerve and relaxes the vocal cords.

Question 18

What is the function of the posterior cricoarytenoid muscle?

Answer 18

The posterior cricoarytenoid muscle is innervated by the recurrent laryngeal nerve and abducts the vocal cords.

Question 19

What is the function of the lateral cricoarytenoid muscle?

Answer 19

The lateral cricoarytenoid muscle is innervated by the recurrent laryngeal nerve and adducts the vocal cords.

Question 20

What is the function of the transverse arytenoid muscle?

Answer 20

The transverse arytenoid muscle is innervated by the recurrent laryngeal nerve and closes the glottis.

Question 21

What is the function of the aryepiglottic muscle?

Answer 21

The aryepiglottic muscle is innervated by the recurrent laryngeal nerve and closes the glottis; it approximates the folds.

Question 22

What is the function of the sternohyoid muscle?

Answer 22

The sternohyoid muscle is innervated by the cervical plexus (C1, C2, C3) and draws the hyoid bone inferiorly.

Question 23

What is the function of the sternothyroid muscle?

Answer 23

The sternothyroid muscle is innervated by the cervical plexus (C1, C2, C3) and draws the thyroid cartilage caudad.

Question 24

What is the function of the thyrohyoid muscle?

Answer 24

The thyrohyoid muscle is innervated by the cervical plexus and hypoglossal nerve (C1 and C2) and pulls the hyoid bone inferiorly.

Question 25

What is the function of the stylopharyngeus muscle?

Answer 25

The stylopharyngeus muscle is innervated by the glossopharyngeal nerve and aids in swallowing.

Question 26

What is the sensory supply of the superior laryngeal nerve (SLN)?

Answer 26

The SLN provides sensory supply above the vocal cords and to the pharynx.

Question 27

What is the motor supply of the internal SLN?

Answer 27

The internal SLN provides motor supply to the cricothyroid muscle.

Question 28

What is the clinical relevance of the RLN?

Answer 28

The RLN is clinically relevant for vocal cord function, pitch modulation, and risk of hoarseness/stridor if injured.

Question 29

What should CRNAs be cautious of during laryngoscopy or suctioning?

Answer 29

Stimulating the glossopharyngeal or vagus nerve can cause bradycardia.

Question 30

What is the function of intrinsic laryngeal muscles?

Answer 30

Control vocal cord tension, length, position, and glottic opening/closure.

Question 31

What are the intrinsic laryngeal muscles?

Answer 31

Cricothyroid, Vocalis, Thyroarytenoid, Lateral Cricoarytenoid, Posterior Cricoarytenoid, Aryepiglottic, Interarytenoid.

Question 32

What innervates all intrinsic laryngeal muscles except the cricothyroid?

Answer 32

Recurrent laryngeal nerve (branch of the vagus nerve).

Question 33

What innervates the cricothyroid muscle?

Answer 33

External branch of the superior laryngeal nerve.

Question 34

What is the function of the cricothyroid muscle?

Answer 34

Tenses and elongates vocal cords by tilting the thyroid cartilage.

Question 35

What is the function of the vocalis muscle?

Answer 35

Fine control of pitch by adjusting vocal cord tension.

Question 36

What is the function of the thyroarytenoid muscle?

Answer 36

Relaxes and shortens vocal cords, lowering pitch.

Question 37

What is the function of the lateral cricoarytenoid muscle?

Answer 37

Adducts the vocal cords (closes the glottis). ## Footnote Assists with voice production and airway protection.

Question 38

What is the function of the posterior cricoarytenoid muscle?

Answer 38

Abducts the vocal cords (opens the glottis/widening the rima glottidi). ## Footnote Only vocal cord abductor; dysfunction can cause airway obstruction.

Question 39

Where is the aryepiglottic muscle located?

Answer 39

Within the aryepiglottic folds.

Question 40

What is the function of the aryepiglottic muscle?

Answer 40

Assists in closing the laryngeal inlet during swallowing. ## Footnote Helps protect the airway from aspiration.

Question 41

What is the structure of the interarytenoid muscle?

Answer 41

Composed of transverse and oblique fibers.

Question 42

What is the function of the interarytenoid muscle?

Answer 42

Adducts arytenoid cartilages, facilitating vocal cord closure. ## Footnote Essential for full glottic closure during phonation and swallowing.

Question 43

What is the Superior Laryngeal Nerve Block?

Answer 43

Anesthetic is injected at the inferior border of the greater cornu of the hyoid.

Question 44

Where is the anesthetic injected for the Superior Laryngeal Nerve Block?

Answer 44

1 mL is injected above the thyrohyoid membrane, then 2 mL is injected 2-3 mm beneath the thyrohyoid membrane.

Question 45

What does aspiration of air indicate during the Superior Laryngeal Nerve Block?

Answer 45

Aspiration of air means the needle is too deep.

Question 46

What is the Transtracheal Block?

Answer 46

The needle is advanced in a caudal direction as it penetrates the cricothyroid membrane.

Question 47

What should the patient do before injection during the Transtracheal Block?

Answer 47

The patient should take a deep breath.

Question 48

What happens during inspiration in the Transtracheal Block?

Answer 48

The patient will cough, spraying the local anesthetic up through the cords.

Question 49

What is the target area for a glossopharyngeal block?

Answer 49

The target area is the posterior tonsillar pillar or posterior pharyngeal wall.

Question 50

What areas does a glossopharyngeal block anesthetize?

Answer 50

It anesthetizes the posterior 1/3 of the tongue, soft palate, oropharynx, tonsillar pillars, and vallecula.