Larynx-Wilson Flashcards
What are the functions of the larynx?
- an airway: connects the pharynx with the trachea
- where the vocal cords are located
- functions as a valve; during swallowing it is completely shutoff to prevent aspiration of food liquid or drinks into the respiratory system; pharynx was descending but makes makes the probability of choking enhanced
- Airway
- Organ of phonation
- Valve during swallowing
Where is larynx located?
IN MALES, THE LOCATION OF THE LARYNX
IS INDICATED BY THE VERY LARGE
LARYNGEAL PROMINENCE
Laryngeal
Prominence
(C4)
What is the skeleton of the larynx? How many are paired/unpaired? What are they?
the skeleton of the Larynx is formed with Hyaline Cartilage
3 unpaired cartilages
3 paired cartilages
What is a distinct feature of the thyroid cartilage?
- unpaired
- inferior horn that will form an synovial joint with the cricoid cartilage
Sexual Differences in Thyroid Cartilage
- in females is broader and smaller
- in males it is prominent (adam’s apple AKA laryngeal prominence), larger and has a sharper angle to it
posteriorly, thyroid cartilage is incomplete (does not form a ring)
What is only cartilage in the respiratory system to form a complete cartilaginous ring?
cricoid cartilage, the only cartilage of the respiratory system that makes a ring
- unpaired cartilage
- posteriorly very broad and high
- anteriorly is very narrow (can be confused with a tracheal ring)
What are the distinct feature of the epiglottis?
- unpaired
- looks like a leaf
- attached to the thyroid cartilage and extends above the hyoid bone
- name means cartilage above the glottis (vocal cords)
-the infraglosal is attached to the ???
Arytenoid cartilage is paired.
- apex with a triangular base
- has a vocal process where the vocal cords attach
- muscular process where the muscles of the larynx will be attaching
- forms a synovial joint with back of the cricoid cartilage
All the cartilage of the larynx except for what are missing from the posterior?
cricoid cartilage
What are the ligaments associated with the larynx?
EXTERNAL (ones you see from the outside of the larynx):
-thyrohyoid membrane: pierced by an opening that allows the internal laryngeal nerve to innervate the upper half of the larynx with sensory and autonomic innervation (sometimes you can do nerve blocks at the thyrohyoid membrane to intubate without choking the pt)
-Medial cricothyroid ligament: important site for performing an emergency laryngotomy; soft spot btw thyroid and cricoid cartilage; would open up if pt is choking or asphyxiating to establish an emergency airway in the infraglottic cavity; can leave a scar behind (more difficult to cover)
INTERNAL
- true vocal ligament: attaches to the vocal process and the thyroid cartilage; vibrates and produces sound
- false vocal ligament AKA vestibular ligament AKA ventricular ligament is right above the true vocal ligaments
What is the difference between the true and false vocal cords?
they lie right on top of each other
- the false vocal cords (vestibular ligament) do not make sounds
- the true vocal cords vibrate and make sound
What are chambers of the larynx? What defines these chambers?
mucous membrane has been removed
-vestibule vestibular ligament (defines)
in between the vestibular ligament and vocal ligament you have the ventricle
ventricle: a deep pouch btw the two vocal cords
vocal ligament (Defines)
- infraglottic
cavity: below the vocal cord
What is a fold?
ligament/muscle covered with a mucous membrane
Why is the larynx shaped the way that it is and why is that important clinically (MRI)?
- its organization is like two truncated cones with tips cut off
- voice production: when you speak you blow out air through your larynx you’re pushing air and trying to increased the speed at which the air is moving the pressure of the air as it goes across the vocal cords; the shape of these truncated cones help focus the air stream right on the vocal cords so the vocal cords vibrate with enough amplitude for you to speak LOUD (to produce sound you can hear); if the air stream or space is too wide the person can only speak as loud as a whispers
-in btw the cones is the narrowest part of the upper part of the respiratory system; if you have edema and the mucous membranes start to swell at the narrow area you would need to perform a laryngotomy to save the person lives
What does the larynx look like during physical examination of the throat?
- light is reflected from the mirror into the pts mouth
- if you strip away all the membrane the vocal
What is the rima glottidis?
- the space around the vocal cords
- the rim of around the glottis (vocal cord)
- gone when the glottis are adducted (closed) and cannot breath in this state
How does the rima glottidis look like when breathing vs. speaking?
- open during breathing
- slit like space during speech
If you have paralysis of one of the intrinsic muscles of the larynx your vocal cords will be?
look like that when you’re speaking ( a small slit)
THE RIMA GLOTTIDIS IS TIGHTLY CLOSED
AND OBSTRUCTS ALL AIRFLOW DURING what?
Swallowing
Choking: prevents aspiration by the closing of the larynx from the pharynx with back bending of the epiglottis; don’t want foreign material to aspirate in the lungs
Valsalva Maneuver: performed by moderately forceful attempted exhalation against a closed airway, usually done by closing one’s mouth, pinching one’s nose shut while pressing out as if blowing up a balloon; bear down to hold up the weight???
What are the two major nerves that innervate the larynx?
superior laryngeal nerve: innervates derivatives of the 4th pharyngeal arch
a. internal laryngeal nerve (sensory)
b. external laryngeal nerve (purely motor)
recurrent laryngeal nerve:
-inferior laryngeal nerve is the terminal branch of this nerve; innervates derivatives from the 6th pharyngeal arch (innervates ONLY the larynx providing sensory/motor innervation)
Describe the Internal and Inferior Laryngeal Nerves Provide Sensory and Secretomotor Innervation to the Larynx.
Internal Laryngeal Nerves provide sensory and visceromotor innervation to everything above the true vocal cords (to the vestibule)
everything below the true vocal cords including the true vocal cords, ventricle, and the infraglottic cavity is innervated by the inferior laryngeal nerve
inferior laryngeal nerve is also the innervation to all laryngeal muscles except the cricothyroid muscle
The Larynx Has 2 Synovial Joints:
Cricothyroid Joint
- cricoid cartilage is the most immobile part of the respiratory system
- thyroid cartilage rocks anteriorly and posteriorly (increases and decreases the tension of the vocal ligaments changing the pitch in sound) ; relaxed is deep and tensed is high pitch
Cricoarytenoid: 2nd Synovial Joint
- if you rotate the vocal process laterally you open the rima glottidis (when you want to breath and talk)
- if you rotate the vocal process medially you obliterate the rima glottidis (when you don’t want to aspirate)
- sliding produces opening and closing of rima glottidis
- the arytenoid cartilages can also tilt back and forth (very mobile); tilt anteriorly to make voice deeper or posteriorly to make voice higher
What are the intrinsic muscles of the larynx?
1) muscle names reflect origin and insertion
2) usually cricoid cartilage serves as origin
3) usually arytenoid cartilage serves as insertion
- POSTERIOR CRICOARYTENOID*
- LATERAL CRICOARYTENOID
- transverse arytenoid
- CRICOTHYROID
What are the functions of the intrinsic muscles of the larynx?
1) Open/Close Rima Glottidis
2) Tense/Relax Vocal Folds (important for pitch production)
3) Close Aditus (laryngeal inlet which is the opening into the larynx)
Describe the
POSTERIOR CRICOARYTENOID m.
rotates the arytenoid cartilage externally opening up the rima glottidis
this is the ONLY muscle of the larynx that opens the rima glottidis
-if you have paralysis of this muscle you can’t breath
LATERAL CRICOARYTENOID m.
- rotates the muscular process internally thus closing the vocal ligaments AKA close the rima glottidis
- ADDUCTOR OF VOCAL LIGAMENT
- when this muscle goes into spasms you cannot breathe
Transverse arytenoid m.
when it contracts it pulls the arytenoid cartilages together; thus closing the rima glottidis
If you choke food into the vestibule, what happens?
- stimulation of the internal laryngeal nerve produces spasms of the muscles that will block breathing
- either remove food from the vestibule or pt dies
CRICOTHYROID m.
- tenses the vocal ligament
- tilts the thyroid cartilage anteriorly thus tensing the vocal cord making the sound pitch higher
- the ONLY muscle innervated by the EXTERNAL laryngeal nerve
thyroarytenoid m.
- it is antagonist to the cricothyroid m.
- runs parallel to the vocal cords/ligament
- pulls thyroid and arytenoid cartilages closer together, thus relaxing the tension in the vocal cords AKA DECREASES TENSION OF VOCAL LIGAMENTS; making voice deeper
What is the vocalis?
- part of the thyroarytenoid m -a specialized part of thyro-arytenoid that attaches to the vocal ligament
- allows for small minute changes in pitch
What is the aryepiglottic
muscle (closes aditus) ?
-goes from the apex of the arytenoid cartilage upwardly to the epiglottis
-the stable part is the arytenoid (what moves is the epiglottis)
-when the muscle contracts the epiglottis goes backward covering up the opening into the larynx preventing food from going into the larynx
-CLOSES ADITUS
(entrance to vestibule of larynx)
-pulls the epiglottis posteriorly and inferiorly, like a trash-can lid
The Epiglottis Prevents Food From
Entering the Trachea
Aryepiglottic muscle assist gravity in pulling that epiglottis down to cover the aditus to prevent food from being aspirated
SVE INNERVATION TO LARYNX
(inferior laryngeal nerve*)
SVE= branchiomotor (Derived from pharyngeal arches)
internal laryngeal nerve is sensory
external laryngeal nerve is motor and goes only to the cricothyroid m.
inferior laryngeal nerve is the terminal branch of the recurrent; goes to all the muscles of the larynx except the cricothyroid; also innervates the true vocal cords and the infraglottic cavity
The Recurrent Laryngeal Nerve Passes Close to the Thyroid Gland:
Describe the course of the recurrent laryngeal nerve which is different on the right and left.
As the nerve on the right goes around the subclavian and goes back towards the larynx passes next to the thyroid gland
On the left side the nerve passes around the arch of the aorta and comes back running in a space btw the esophagus and the trachea, closely related to the thyroid gland
If we reflect the thyroid gland anteriorly we can see the laryngeal nerve and the external laryngeal nerve.
The Inferior Laryngeal Nerve May Be Injured During a Thyroidectomy or even edema to the thyroid gland.
What are the changes you see with lesion to the inferior laryngeal nerve?
1) voice changes (hoarseness)
2) accumulation of saliva in piriform recess (stop swallowing reflex)
3) fixed vocal fold on one side
when you look in the throat, you will notice an accumulation of saliva, usually the salvia would stimulate swallowing but if you have damage to the inferior laryngeal nerve you have paralysis of the laryngeal pharynx and thus there is no swallowing reflex
the vocal cord is not moving but is adducted so when a person tries to speak there is no control over the vocal ligament; the rima glottidis is too large so you can only speak in a whisper
What are the two muscles that close the rima glottidis?
- lateral cricoarytenoid
- transverse arytenoid
