Larynx

Question 1

Cricothyroid Muscle

Answer 1

Origin: External surface of the cricoid arch

Insertion: Inferior thyroid lamina

Nerve: External laryngeal nerve

Action: Lengthen (tighten) vocal cords

Question 2

Posterior Cricoarytenoid Muscle

Answer 2

Origin: Posterior cricoid lamina

Insertion: Muscular process of arytenoid

Nerve: Inferior laryngeal nerve

Action: Pulls posteriorly on muscular process (abducts
vocal cords)

Question 3

Lateral Cricoarytenoid Muscle

Answer 3

Origin: Cricoid arch

Insertion: Muscular process of arytenoid

Nerve: inferior laryngeal nerve

Action: Pulls anteriorly on muscular process (adducts
the vocal cords)

Question 4

Arytenoid Muscle

Answer 4

Origin: Body of arytenoid

Insertion: Contralateral arytenoid

Nerve: Inferior laryngeal nerve

Action: Adducts arytenoids (and adducts vocal cords)

Question 5

Thyroarytenoid Muscle

Answer 5

Origin: Thyroid lamina

Insertion: Body of arytenoid

Nerve: Inferior laryngeal nerve

Action: Shorten (relax) vocal cords

Question 6

Vocalis Muscle

Answer 6

Origin: Vocal process of arytenoid

Insertion: Vocal ligament

Nerve: Inferior laryngeal nerve

Action: Shorten (relax) vocal cords

Question 7

Superior Laryngeal Nerve

Answer 7

Branch of Vagus (CN X)

Two Branches:
- External laryngeal nerve: Only motor to cricothyroid muscle

• Internal laryngeal nerve: Pierces thyrohyoid membrane; sensation to supraglottic region

Question 8

Inferior Laryngeal Nerve

Answer 8

Continuation of recurrent laryngeal nerve (from Vagus CN X)

Passes posterior to cricothyroid joint

Motor to all internal laryngeal muscles

Sensation to glottis and infraglottic cavity

Unilateral damage: Weak, breathy voice
Bilateral damage: little to no phonation at all

Question 9

Cough Reflex

Answer 9

Highly sensitive mucosa of the supraglottic space protects vocal folds and infraglottic cavity

Sensory Limb: Vagus (CN X)
Motor Limb: Vagus (CN X)