Larynx Flashcards
What are the functions of the larynx?
- Allows air passage in & out of the trachea
- Protective sphincter preventing foreign bodies from entering the airway
- Organ of phonation (speech production)
What is crucial during swallowing concerning the larynx ?
elevation
What is superior and inferior to the larynx?
- Superiorly opens into the laryngopharynx forming its anterior wall (epiglottis)
- Inferiorly continues into the trachea
What type of cartilage are the laryngeal cartilages?
all hyaline except the epiglottis which is elastic
What are the laryngeal cartilages?
epiglottis (unpaired)
cricoid (unpaired)
thyroid (unpaired)
arytenoid (paired)
corniculate (paired)
cuneiform (paired)
Which of the cricoid cartilages is the only complete ring?
cricoid
Which cartilages cannot be viewed unless the larynx is taken apart?
arytenoid
corniculate
cuneiform
Why is the epiglottis made of elastic cartilage?
it allows the epiglottis to be flexible and resilient, which helps it perform its function of protecting the airway and preventing aspiration
What is the structure of the thyroid cartilage?
what is the significance in males
- Left & right laminae
- The laminae fuse anteriorly as the laryngeal prominence which is more obvious in males (Adam’s apple)
What is the shape of the epiglottis and what is it attached to?
- Leaf-like plate of elastic cartilage (why?)
- Attached to the back of the thyroid cartilage
What is between the thyroid cartilage and hyoid bone?
thyrohyoid membrane
extrinsic
What is anterior and posterior to the thyrohyoid membrane?
thickening of thyrohyoid forms;
anterior: median thyrohyoid ligament
posterior: lateral thyrohyoid ligaments
extrinsic
What is from the arytenoid cartilage to thyroid cartilage to epiglottis?
extrinsic or intrinsic
intrinsic
quadrangular membrane
What is from cricoid to arytenoid to thyroid cartilage?
extrinsic or intrinsic
intrinsic
cricothyroid ligament (cricovocal membrane)
What is cricothyroid ligament thickened anteriorly as?
median cricothyroid ligament
What is the lateral median cricothyroid ligament called?
conus elasticus
What is the superior free edge of the cricothyroid ligament?
vocal ligament
What are the laryngeal folds?
Mucous membrane lines the inner aspect of the larynx creating folds over the free edges of the previously described membranes & ligaments
What are the names of the laryngeal folds?
- aryepiglottic fold
- vestibular folds (mucosa over vestibular ligamentt)
- vocal cords (mucosa over vocal ligament)
Where is the aryepiglottic fold and what does it form?
- Over the superior free edge of the quadrangular membrane
- Forms the laryngeal inlet which is the protective sphincter of the larynx
Where are the vestibular folds formed?
false vocal cords
formed over the inferior free edge of the quadrangular membrane (aka vestibular ligament)
What is the inferior free edge of the quadrangular membrane called?
vestibular ligament
Where are the vocal folds formed?
true vocal cords
formed over the superior free edge of the cricothyroid ligament (aka vocal ligament)
What is the superior free edge of the cricothyroid ligament called?
vocal cord
What is the space between the vocal folds called?
rima glottidis/glottis
Why are the vestibular folds called false vocal cords?
they are not involved in phonation in speech production
What are the roles of the intrinsic laryngeal muscles?
- Open or close the rima glottidis
- Alter the tension of the vocal folds (true vocal cords)
- Open or close the laryngeal inlet
What do the vocal and vestibular folds play an important role in?
coughing, sneezing & raising the intra-abdominal pressure during parturition (childbirth), micturition (urinating), defecation & lifting heavy objects
What muscle opens the rima glottidis and how?
The posterior cricoarytenoid
muscle is the only muscle to abduct the vocal folds opening the rima glottidis
What muscles close the rima glottidis?
- Transverse arytenoid
muscle - Lateral cricoarytenoid
muscle
What does lengthening and shortening of the vocal folds do?
alters tension and pitch of the voice
- Lengthened vocal folds = increased tension = higher pitch
- Shortened vocal folds = reduced tension = lower pitch
What muscle shortens vocal folds?
thyroarytenoid muscle
What is the upper part of the thyroarytenoid muscle called?
vocalis
What muscle lengthens vocal folds?
cricothyroid muscle
What muscle closes the laryngeal inlet?
oblique arytenoid muscle acting as a “purse-string”
What muscle opens the laryngeal inlet?
by descent of the larynx (& pharynx) mainly by elastic recoil
What is the motor nerve supply of the intrinsic muscles?
- All intrinsic muscles of the
larynx are supplied by the recurrent laryngeal nerve with one exception! - Cricothyroid is supplied by the external branch of the superior laryngeal nerve
all vagus
What is the sensory supply of the larynx?
- Sensation just above the vocal
folds is supplied by the internal branch of the superior laryngeal nerve - Sensation below the vocal folds is supplied by the recurrent laryngeal nerve
all vagus
What is the larynx’s role in quiet respiration?
- Vocal & vestibular folds are abducted
- A triangular “open” rima glottidis
What is the larynx’s role in forced inspiration?
- Rima glottidis is forcefully & more widely opened by the posterior cricoarytenoid muscle
How is speech produced?
- Vocal folds are adducted
- Vestibule is open
- Rima glottidis is closed & air is forced through causing vibration
- Vocal fold length & tension, for pitch of voice, are altered by a fine interplay between the cricothyroid & thyroarytenoid (with its vocalis)
How does phonation occur?
speech without articulation
- Vocal folds adducted and stridulating as air is forced between them
- Vestibule open
What happens in effort closure?
for heavy lifting, etc
- Vocal & vestibular folds are
adducted - Rima glottidis is closed
- Vestibule is also closed
What is anatomically related to the thyroid gland?
vessels, cartilage, glands, nerves and structures
trachea
ijv
cca
thyroid cartilage
cricoid cartilage
superior parathyroid gland
inferiror parathyroid
right recurrent laryngeal nerves
left recurrent laryngeal nerve
What is the midline pyramidal lobe a remnant of?
thyroglossal duct
