Airway anatomy

Question 1

Classification of laryngeal muscles

Answer 1

intrinsic- phonation & control of vocal cords

extrinsic- supports larynx inside the neck & assists with swallowing

Question 2

The superior laryngeal nerve innervates which intrinsic muscle:

Answer 2

cricothyroid muscles

think SCAR

Question 3

The recurrent laryngeal nerve innervates which intrinsic muscles:

Answer 3

All other muscles (except cricothyroid muscles)

mnemonic SCAR

Question 4

What is the role of the lateral cricoarytenoids?

Answer 4

Let’s close airway

Adducts

Question 5

What is the role of the posterior cricoarytenoids?

Answer 5

Please come apart- abducts

Question 6

What is the role of the cricothyroid muscle?

Answer 6

Cords tense

Question 7

What is the role of the thyroarytenoid muscle?

Answer 7

they relax

Question 8

What muscles are considered extrinsic?

Answer 8

omohyoid
sternohyoid
thyrohyoid
digastric
stylohyoid
mylohyoid

Question 9

What are the three cranial nerves that innervate the upper airway?

Answer 9

Trigeminal
Glossopharyngeal
Vagus

Question 10

Describe the branches of the trigeminal nerve.

Answer 10

V1: Opthalmic
V2: Maxillary
V3: Mandibular

Question 11

What is the sensory and motor function of the ophthalmic branch of the trigeminal nerve?

Answer 11

sensory: nares & anterior 1/3rd of nasal septum
motor: 0

Question 12

What is the sensory & motor function of the maxillary branch of the trigeminal nerve?

Answer 12

sensory: turbinates & septum
motor: none

Question 13

What is the sensory & motor function of the mandibular branch of the trigeminal nerve?

Answer 13

Sensory: anterior 2/3rd of tongue
Motor: mastication

Question 14

If the patient gags during fiberoptic intubation then this nerve was not appropriately anesthetized:

Answer 14

glossopharyngeal

Question 15

Describe the sensory function of the glossopharyngeal nerve.

Answer 15

oropharynx- soft palate, tonsils, vallecula, posterior 1/3rd of tongue, anterior side of epiglottis

Question 16

Describe the motor function of the glossopharyngeal nerve.

Answer 16

swallowing

phonation

Question 17

Describe the sensory function of the recurrent laryngeal nerve.

Answer 17

below level of vocal cords–> trachea

Question 18

Describe the motor function of the recurrent laryngeal nerve.

Answer 18

All intrinsic muscles EXCEPT cricothyroid

Question 19

Describe the branches of the superior laryngeal nerve.

Answer 19

External branch (SEM)- no sensory, motor to cricothyroid muscles
Internal branch (SIS)- posterior side of epiglottis--> level of vocal cords, no motor

Question 20

Describe the difference between the right & left recurrent laryngeal nerves and which one is more likely to have damage.

Answer 20

Right- loops under the subclavian

left- loops under the aortic arch- higher likelihood of damage

Question 21

Damage to either side of the recurrent laryngeal nerve can result from:

Answer 21

external pressure from ETT/LMA
surgery: thyroid/ parathyroid
neck stretching
neck tumor

Question 22

Damage to the recurrent laryngeal nerve on the left side only includes

Answer 22

Left atrial enlargement
PDA ligation
aortic arch aneurysm
thoracic tumor

Question 23

Describe presentation for injury to the superior laryngeal nerve.

Answer 23

hoarseness

Question 24

Describe unilateral versus bilateral injury to the recurrent laryngeal nerve.

Answer 24

unilateral- hoarseness, ipsilateral loss of innervation to muscle that abducts vocal cord
bilateral- stridor, respiratory distress- airway emergency (acute) vs. chronic- well tolerated