Larynx Flashcards
What are the 3 single and 3 paired laryngeal cartilages? Where do they extend?
larynx extent from C3-C6
3 single (3): epiglottis, thyroid, cricoid 3 paired (so 6) : arytenoid, corniculate, cuneiform
Describe the extrinsic and intrinsic membranes of the larynx
extrinsic (2) and intrinsic (2)
extrinsic - thyrohyoid membrane (pierced by internal laryngeal nerve and superior laryngeal vessesl)
cricotracheal ligament
intrinsic (VOCAL CORDS) quadrangular membranes (upper - aryepiglottic fold) lower- VESTIBULAR LIGAMENT/FALSE VOCAL CORD
cricothyroid ligament- forms VOCAL LIGAMENT (true vocal fold)
What is found on either side of aryepiglottic fold?
PISIFORM FOSSA
Name and compare the actions of the laryngeal muscles.
cricothyroid (tensor) -stretches and tenses vocal ligament
posterior cricoarytenoid (ABductor) -abducts vocal folds
lateral cricoartenoid (ADductor of vocal folds)
transverse and oblique artyenoid (ADductor artytenoid cartilages)
thyro-arytenoid and vocalis (relaxor) - relaxes posterior vocal ligament while maintaining (or increasing) tension of anterior part
What does the larynx do? What is it the source of?
It protects the entrance of the tracheobronchial tree as the epiglottis guards the laryngeal inlet.
Larynx is the source of voice, which is generated by the vibration of the vocal cords
What do the intrinsic muscles of the larynx support?
vocal cords which are Vestibular ligament (false vocal cord) and Vocal ligaments (true vocal cord)
laryngeal ventricle lies in between
What are the muscles of the larynx supplied by? (MOTOR)
MOTOR - all the muscles are supplied by inferior laryngeal nerve (terminal part of recurrent laryngeal nerve of Vagus)
except Cricothyroid muscle which is supplied by External laryngeal nerve of superior laryngeal of Vagus
Describe the location of the larynx.
it is continuous with the laryngopharynx superiorly and with trachea inferiorly at level of C6
Describe the epiglottis.
What forms the inlet?
bodyguard of larynx.
aryepiglottic fold with the epiglottis and arytenoids forms the inlet
Which muscles develop from which arch?
All laryngeal muscles develop from the 6th arch
Cricothyroid develops from 4th arch (this is why it is supplied by external laryngeal nerve of X while all other are supplied by recurrent laryngeal nerve)
What is the only ABductor of the vocal cords?
What else does it do?
posterior crico-atytenoid.
it is also the only opener of rima glottis. Bilateral paralysis or injury to recurrent laryngeal nerve is fatal bc it leads to closure of rima glottis.
Describe the upper and lower parts of the larynx in regards to their SENSORY innervation and blood supply.
above vocal cords- internal laryngeal N of Sup. Laryngeal N. and superior laryngeal A. of superior thyroid artery (off external carotid a)
below vocal cords- recurrent laryngeal nerves of X.
inferior laryngeal A of inf. thyroid A. (off thyrocervical trunk)
What should a surgeon be mindful of during a thyroidectomy?
the blood supply of the thyroid gland is closely related to the nerve supply of the larynx so the surgeon should take care to save the nerves or else voice could be damaged/changed
What is on either side of aryepiglottic folds?
What is significant about this?
on their sides of aryepiglottic folds PIRIFORM FOSSA is located (piriform fossa and valleculae are common sites for foreign body)
Removal of foreign body from it may damage the branches of internal laryngeal nerve…leads to loss of sensation of upper 1/2 of larynx
What does the cricothyroid do?
What is it an exception for?
Laterally rotates the thyroid cartilage, and pulls it downwards to tighten the vocal cords, increasing the vocal pitch.
NERVE SUPPLY: External branch of superior laryngeal nerve.
