Larynx Flashcards
Function of the Larynx
Serves as valve to guard air passages to maintain patent airway, particularly during swallowing.
Also serves in phonation (the voicebox)
Name the 3 single cartilages of the larynx
Epiglottis, Thyroid, and Cricoid
Name the 3 paired cartilages of the larynx (for a total of 6 cartilages)
Arytenoid, Corinculate and Cuneiform (2 of each)
Corinculate and Cuneiform form the pyramid like structures along the aryepiglottic fold..
Only closed ring in the larynx
Cricoid
Which vertebrate does the larynx coincide with?
C3-C6
Where does the end of the epiglottis attach and via what ligament?
It attaches to the thyroid via the thyro-epiglottic ligament.
What differentiates a ligament from a fold?
A fold is covered in a mucous membrane
Aryepiglottic fold
Place where the arytenoids and the epiglottis meet. Forms the opening of the larynx (laryngeal inlet)
What is the border of the laryngeal inlet?
The Aryepiglottic fold with the Epiglottis and the arytenoids
Function of the epiglottis
To guard the laryngeal inlet
Piriform Fossa
Found on either side of the aryepiglottic fold. Common site for a foreign body to get stuck. Removal of the foreign body may damage the branches of the internal laryngeal nerve which leads to loss of sensation of the upper 1/2 of the Larynx
The two most common sites for foreign bodies to get stuck in the larynx.
Piriform fossa and valleculae
Most common dissection cut to view larynx
Mid-Sagittal
What pierces the thyrohyoid membrane?
The internal laryngeal nerve and the superior laryngeal blood vessels
All of the movement of the larynx happens in association with what?
The cricoid cartilage
The two joints associated with the cricoid cartilage
What kind of joints are they?
- Cricothyroid joints
- Cricoarytenoid joints
Both of these are synovial joints.
What makes up the arytenoid cartilage?
Two pyramids with two processes– vocal process for the vocal cords and muscular process
Where are vocal cords inserted?
Between vocal process of arytenoid, and the thyroid cartilage.
The three important cartilages which allow you to speak.
Cricoid, Arytenoid, and Thyroid
Intrinsic Membranes
Quandrangular and Crico-thyroid
Quandrangular membranes
There are 2 of these membranes. They are stretched between the epiglottis and the arytenoids, and form both an upper and lower borders.
The upper yields: The Aryepiglottic fold
The lower yields: Vestibular ligament aka the FALSE VOCAL FOLD
Crico-thyroid ligamentor membrane
Aka Conus Elasticus
The upper free border of this membrane forms the vocal ligament aka the TRUE VOCAL FOLD
The space between the vocal folds
Rima glottis
The structures of the Interior of the Larynx from above heading downwards.
- Laryngeal inlet (Piriform fossa found on either side)
- Vestibule
- Vestibular Folds or ligament (False Cords)
- Ventricle
- Vocal folds (True Cords)
- Infraglottic Cavity
Where is the Valsalva maneuver performed? What do you do if that fails?
The infraglottic cavity.
If it fails, you enter the infraglottic cavity via a cricothyrotomy.
Anything after the true vocal cords is what?
Infraglottic cavity
Blood vessels and lymphatics of the true vocal cords
There are none. It is avascular and has no lymphatics.
The 6 muscles of the Larynx
(1) Cricothyroid
(2) Posterior Cricoarytenoid
(3) Lateral Cricoarytenoid
(4) Transverse Arytenoid
(5) Oblique Arytenoid
(6) Thyro-arytenoid and Vocalis
Function of the Cricothyroid Muscle
Stretches and tenses the vocal ligament
Function of the Posterior Cricoarytenoid Muscle
The only ABDuctor in the vocal cords. This is the only way the vocal cords can open up to allow air to pass through.
Function of the Lateral Cricoarytenoid, Transverse Arytenoid, and the Oblique Arytenoid Muscles
All function to ADDuct the vocal cords
Function of the Thyro-arytenoid/Vocalis muscle
Relaxes vocal cords allowing you to WHISPER.
What sits on top of the cricothyroid muscle?
The arytenoid
What is unique about the innervation of the cricothyroid muscle? How did that happen?
It is supplied by the External laryngeal branch of the superior laryngeal of vagus (CN X). All other muscles in the larynx are supplied by the recurrent laryngeal of vagus.
This is because the cricothyroid muscle developed in the 4th pharyngeal arch, whereas the others came from the 6th arch
In what way do the vocal cords act as a “watershed”?
Everything above the vocal cords have different SENSORY innervation and blood supply than the things below the vocal cords.
Above (both penetrate the thyrohyoid membrane):
- Internal laryngeal n. of Sup. Laryngeal n.
- Sup. laryngeal A. of Sup Thyroid A.
Below:
- Recurrent laryngeal N. of CN X
- Inf. laryngeal A. of Inf. Thyroid A.
Internal vs External laryngeal
External- Motor
Internal- Sensory
What organ is past the vocal cords?
Trachea
Where is internal laryngeal usually tagged?
Usually tagged right next to epiglottis. It can also be tagged externally, next to superior thyroid artery.
The blood supply of the thyroid gland is closely related to…
The nerve supply of the larynx, which is why during a thyroidectomy the surgeon should take care to save the nerves.
