Larynx Flashcards
What is the primary role of the larynx?
prevent aspiration of foreign bodies into the lower respiratory system
How does the position of the larynx change in adults and why?
in infants –> begins at C1, located at the height of the jawbone to allow them to breathe & swallow simultaneously (so they can breathe while breastfeeding)
in adults –> begins at C3, descends & is located in neck –> evolutionary advantage –> can produce certain sounds. Adult humans can’t introduce air while swallowing (
(must elevate larynx & move it anteriorly when swallowing to prevent foreign bodies entering)
What happens when aspiration of foreign bodies occurs?
action of true & false vocal cords acts as part of the cough reflex mechanism to expel them (water, oral secretion, food, etc)
What is the main difference b/w chimpanzee & human oral cavity & larynx?
- longer oral cavity & much lower larynx in humans
Which organism has the most primitive larynx?
bichir lungfish (Polypterus) -- in Nile river consists only of a muscular sphincter
A communication b/w respiratory & digestive pathways is maintained in adult humans too. True or false & why?
true, bc during development the communication of respiratory diverticulum w/ the future oropharynx is established
result = a crossing b/w these 2 routes as air enters from nasal cavity & food from oral cavity
Briefly describe the embryological development of the larynx
- aperture of larynx = a slit called LARYNGOTRACHEAL GROOVE which opens into the respiratory diverticulum
- slit/groove starts to look like a T –> LARYNGEAL INLET
The cartilage of the larynx derives from the mesodermal mesenchyme of which 2 pharyngeal arches?
4th & 6th
Where do the intrinsic laryngeal muscles originate from and what’s their innervation?
6th pharyngeal arch
RECURRENT NERVE or inferior laryngeal n (branch of vagal n)
Which arch does the crico-thyroideus originate from? Innervation?
4th
an intrinsic laryngeal muscle
superior laryngeal n
Are skeletal muscles of the larynx voluntary or involuntary?
Involuntary, despite being striated –> bc the have branchial/pharyngeal origin
the larynx is a ____________ canal attached to the ____ bone, it extends from the base of the _____ to the ______ in front of vertebrae C_ to C_
fibrocartilaginous hyoid tongue trachea C3 to C6
Which muscles are associated to the hyoid bone?
muscles of the floor of oral cavity &
those that move the larynx
Which are the 4 large cartilages of the larynx?
- THYROID - shield-shape, hyaline cartilage
- CRICOID - most caudal, at base of larynx, ring-like, hyaline “
- ARYTENOIDS - resemble ampullae, hyaline & elastic “
- EPIGLOTTIS - above the glottis, elastic “, most imp functionally –> moved when swallowing
Which are the 4 large cartilages of the larynx?
- THYROID - shield-shape, hyaline cartilage
- CRICOID - most caudal, at base of larynx, ring-like, hyaline “
- ARYTENOIDS - resemble ampullae, hyaline & elastic “
- EPIGLOTTIS - above the glottis, elastic “, most imp functionally –> moved when swallowing
Which are the 2 small cartilages of the larynx?
- CORNICULATE - resemble small horns, associated to superior surf of arytenoid
- CUNEIFORM - within a ligamentous device –> QUADRANGULAR MEMBRANE
The larynx is highly _____, it can be moved down, forward, & backward thanks to the action of ______ muscles
mobile
extrinsic
What is the function of the false vocal cords?
protective device of region where true vocal cords are –> RIMA GLOTTIS
Posteriorly, the larynx is completed by the ______
pharynx
What are the main features of the cricoid cartilage?
- most caudal
- in communication w/ the 1st tracheal ring
- shape = signet ring
- palpated below the laryngeal prominence (Adam’s apple) of thyroid cartilage
- 2 articular facets
1. inferior –> articulation w/ inf horn of thyroid cartilage
2. superior –> “ w/ arytenoids
Describe the crico-vocal membrane
- AKA cricothydois membrane/ligament
- closes the space left empty b/w thyroid & cricoid cartilages
boundaries:
- from cricoid’s superior margin to arytenoids’ anterior processes & thyroid cartilage’s internal angle
What is the median cricothyroid ligament?
anterior & medial portion of crico-vocal membrane –> where it is thicker
What action on the vocal ligaments alter the pitch of our voice?
when thyroid cartilage is lifted up –> vocal ligaments stretch –> more tension –> alters pitch of voice
What is the conus elasticus?
the inferior part of the fibroelastic membrane of larynx
delimits an opening in the middle
The epiglottis is a ___-like structure. It attaches where the 2 vocal ligaments converge, on the ______ angle of thyroid cartilage
leaf-like
internal
Which muscles insert on the cricoid cartilage?
A - Intrinsic
- cricothyroid
- cricoarytenoid (posterior & lateral)
B - Extrinsic
- cricopharyngeal
- part of inferior constrictor
- esophageal longitudinal fibers
cricothyroid & thyroarytenoid cover the cricothyroid membranes from the outside
What are the main features of the thyroid cartilage?
- laryngeal prominence on midline from which 2 laminae (plates) extend
- thyroid notch –> reference pt for surface anatomy, easily palpable
- oblique line –> insertion of extrinsic laryngeal muscles
- 2 superior & 2 inferior horns
- inferior horn –> articulates w/ inferior facets of cricoid
- superior horn –> attachm of lateral THYROHYOID LIGAMENTS
What is another term for the laryngeal prominence?
Adam’s apple ;)
What converges at the thyroid angle?
the 2 vocal cords
What is the significance of a more acute/narrower thyroid angle in men?
consequence = laryngeal prominence is more palpable in men
longer vocal cords in men –> lower pitch voice
think of guitar strings
Where is the thyrohyoid membrane thicker?
- anteriorly –> it becomes the median thyrohyoid ligament
2. laterally & posteriorly –> forming lateral thyrohyoid ligaments
Where are TRITICEAL cartilages found?
within the lateral thyrohyoid ligaments
Which 2 things make the larynx susceptible?
- airway thru the larynx is an open passage –> need activation of mechanism that closes it by the epiglottis
if larynx is not correctly positioned –> anything that enters can proceed to the airways - since the larynx has a fibrocartilaginous structure –> its more fragile –> doesn’t recover spontaneously from a crush (unlike muscular struc of esophagus)
What are the main features of the epiglottis?
- leaf-like struc
- elastic cartilage
- connected via thyro-epiglottic ligament to internal angle of thyroid cartilage
- does NOT articulate w/ any other cartilage –> so has high mobility
What role of the aryepiglottic folds play in the protective mechanism during swallowing?
- act as rampant to larynx during swallowing –> so food slides down on sides of larynx instead of entering
Where is the quadrangular membrane?
from the free lateral margins of epiglottis –> extends to superior margin of arytenoid cartilage
The free margins of the quadrangular membrane forms the _________ ligaments
vestibular
What is the conus elasticus ?
= floor of the laryngeal inlet
- a fibroelastic membrane
- AKA cricothyroid membrane
- mainly elastic tissue.
- anterior and two lateral portions :
1. anterior part or middle cricothyroid ligament (ligamentum cricothyreoideum medium;
2. central part of cricothyroid membrane) is thick and strong, narrow above and broad below
What is the glottis?
the territory b/w the true vocal cords & false vocal cords
False vocal cords = ?
= vestibular ligaments + mucosa
True vocal cords = ?
= vocal ligaments + mucosa
What are the main features of the arytenoids (cartilages)?
- small pyramid-like
- 2 processes
1. vocal process – insertion of vocal ligament/ true vocal cord
2. muscular process - apex –> articular facet for CORNICULATE cartilage
Which are the intrinsic ligaments of the larynx?
they form the fibroelastic membrane of the larynx
- cricothyoid ligaments/ membrane
- forms inferior part of fibroelastic membrane aka CONUS ELASTICUS.
- free upper margins form VOCAL ligaments (core of the true vocal cords) - quadrangular membrane
- formed by aryepiglottic folds
- free lower margins form VESTIBULAR ligaments (core of false vocal cords)
Which are the extrinsic ligaments of the larynx?
- Thyrohyoid membrane - reinforced by lateral & medical thyroid ligaments
- Thyroepiglottic ligaments - from stem of epiglottis to angle of thyroid cartilage
- Crico-tracheal ligament - from cricoid to 1st tracheal ring
- Hyo-epiglottic ligament - from dorsal surf of epiglottis to hyoid
