larynx: laryngeal muscles

Question 1

what are the groups of laryngeal muscles?

Answer 1

extrinsic laryngeal muscles

intrinsic laryngeal muscles

Question 2

which muscles make up the extrinsic laryngeal muscles?

Answer 2

suprahyoid muscles

infrahyoid muscles

Question 3

function of suprahyoid muscles (extrinsic laryngeal muscles)?

Answer 3

elevate hyoid and larynx (swallowing + phonation)

Question 4

function of infrahyoid muscles (extrinsic laryngeal muscles)?

Answer 4

depress hyoid and larynx (balance position of hyoid bone)

Question 5

function of the intrinsic laryngeal muscles?

Answer 5

move the laryngeal components, altering the length and tension of the vocal cords and size and shape of rima glottidis

Question 6

what are the intrinsic laryngeal muscles supplied by?

Answer 6

recurrent laryngeal nerve except cricothyroid muscle

Question 7

what is the function of cricothyroid muscle and what is it supplied by?

Answer 7

tenses vocal cords

supplied by external laryngeal nerve (from superior laryngeal nerve)

Question 8

vascular supply to the larynx?

Answer 8

from superior and inferior laryngeal arteries

Question 9

what is superior laryngeal artery a branch of?

Answer 9

superior thyroid artery

ECA –> superior thyroid artery –> superior laryngeal artery

Question 10

what does superior laryngeal artery accompany?

Answer 10

internal branch of superior laryngeal nerve

Question 11

what is the inferior laryngeal artery a branch of?

Answer 11

inferior thyroid artery

subclavian artery –> thyrocervical trunk –> inferior thyroid artery –> inferior laryngeal artery

Question 12

what does the inferior laryngeal artery accompany?

Answer 12

the inferior laryngeal nerve

Question 13

venous drainage of the larynx?

Answer 13

superior and inferior laryngeal veins

Question 14

summary of nerve, artery and veins to larynx

Answer 14

superior and inferior laryngeal arteries, veins and nerves

superior laryngeal nerve has internal and external branches

Question 15

what does the internal branch of superior laryngeal nerve supply?

Answer 15

sensory to supraglottic region

Question 16

what does external branch of superior laryngeal nerve supply? function?

Answer 16

motor to cricothyroid (tenses vocal cords, tense larynx to aid phonation)
only muscle to tense vocal cords

Question 17

what does the recurrent laryngeal nerve supply?

Answer 17

sensory to subglottic region

motor to intrinsic muscles

Question 18

where do superior (internal + external) and recurrent laryngeal nerves arise from?

Answer 18

vagus nerve

Question 19

what does superior laryngeal nerve pierce?

Answer 19

thyrohyoid membrane

Question 20

what are superior and recurrent laryngeal nerves accompanied by?

Answer 20

arterial branches from superior and inferior thyroid arteries

Question 21

where does recurrent laryngeal nerve travel?

Answer 21

runs up the trachea-oesophageal groove
can lead to hoarseness of voice if damaged
nerve has long course, so lots of different pathology could be caused

Question 22

where do recurrent laryngeal nerve hook?

Answer 22

right - under subclavian artery

left - arch of aorta

Question 23

what are causes of recurrent laryngeal nerve palsy?

Answer 23

idiopathic
laryngeal cancer
thyroid disease (benign / malignant)
trauma (including iatrogenic e.g. thyroidectomy)
cervical lymphadenopathy
oesophageal cancer
apical lung cancer (pancoast)
aortic aneurysm
neuropathic (DIABETES)

Question 24

what is an investigative method of larynx?

Answer 24

stroboscopy

visualise vocal fold vibration. It uses a synchronized, flashing light passed through a flexible or rigid telescope