Functional Anatomy of Respiration and Phonation: Musculature and Innervation

Question 1

6 intrinsic muscles of the larynx

Answer 1

• Posterior cricoarytenoid
• Lateral cricoarytenoid
• Transverse arytenoid
• Oblique arytenoid
• Thyroarytenoid
• Cricothyroid

Question 2

Function of posterior cricoarytenoid

Answer 2

• Rotates arytenoids laterally
• Abducts vocal cords

Question 3

Function of lateral cricoarytenoid

Answer 3

• Rotates arytenoids medially
• Adducts vocal cords

Question 4

Function of transverse arytenoid

Answer 4

• Adducts arytenoids
• Adducts vocal cords

Question 5

Function of oblique arytenoid

Answer 5

• Adducts arytenoids
• Adducts vocal cords

Question 6

Function of thyroarytenoid

Answer 6

Shortens vocal ligaments

Question 7

Function of cricothyroid

Answer 7

• Flexion of cricothyroid joint
• Lengthens vocal ligaments

Question 8

Which nerve supplies all branches to the intrinsic muscles of the larynx?

Answer 8

Vagus nerve

Question 9

Which nerve branches from the vagus superior to the hyoid to supply the larynx?

Answer 9

Superior laryngeal nerve

Question 10

Branches of the superior laryngeal nerve

Answer 10

• External branch
• Internal branch

Question 11

Where do each of the branches of the superior laryngeal nerve pass and to innervate what?

Answer 11

• E = inferiorly to innervate cricothyroid
• I = pierces through thyrohyoid membrane to innervate mucous membrane superior to and including vocal fold

Question 12

Which nerve branches off the vagus more inferiorly to innervate the larynx?

Answer 12

Recurrent laryngeal nerve

Question 13

Where does the left recurrent laryngeal nerve branch and pass?

Answer 13

• Level of arch of aorta
• Loops posteriorly under the arch and passes superiorly to larynx

Question 14

Where does the right recurrent laryngeal nerve branch and pass?

Answer 14

• Level of right subclavian artery
• Loops posteriorly under the artery passes superiorly to larynx

Question 15

What is innervated by the recurrent laryngeal nerve?

Answer 15

• Intrinsic muscles of larynx (except cricothyroid)
• Mucosa of infraglottic space

Question 16

Which artery supplies the upper regions of the larynx?

Answer 16

Superior laryngeal artery

Question 17

Origin of superior laryngeal artery

Answer 17

Common carotid –> External carotid –> Superior thyroid –> Superior laryngeal

Question 18

Where does the superior laryngeal artery pass to enter the larynx?

Answer 18

Through thyrohyoid membrane with internal branch of superior laryngeal nerve

Question 19

Which artery supplies the lower regions of the larynx?

Answer 19

Inferior laryngeal artery

Question 20

Origin of inferior laryngeal artery

Answer 20

Subclavian –> thyrocervical trunk –> inferior thyroid –> inferior laryngeal

Question 21

Superior venous drainage of larynx

Answer 21

Superior laryngeal vein –> superior thyroid vein –> internal jugular vein

Question 22

Inferior venous drainage of larynx

Answer 22

Inferior laryngeal veins –> left brachiocephalic vein

Question 23

What does Semon’s law state and why?

Answer 23

• Partial transection of recurrent laryngeal nerve is worse than full transection
• Partial knocks out only abductor but not all adductors of vocal cords
• Vocal cords can be shut but not reopened, so patient cannot breathe

Question 24

Groups of the extrinsic muscles of the larynx

Answer 24

• Suprahyoid muscles
• Infrahyoid muscles

Question 25

Suprahyoid muscles

Answer 25

• Digastric
• Stylohyoid
• Mylohyoid
• Geniohyoid

Question 26

Infrahyoid muscles

Answer 26

• Thyrohyoid
• Sternohyoid
• Sternothyroid
• Omohyoid