Sievert: Larynx, Nasal Cavity Flashcards
What is the opening of the larynx called?
the aditus
What happens around the laryngeal opening during swallowing?
the larynx gets pulled up
the tongue pushes back
the epiglottis gets pushed down closer to the posterior aspect of the cricoid cartilage
What is the area from the aditus to the vestibular folds?
the vestibule
What is the area between the true and false vocal folds?
the ventricle
What is the area below the true vocal folds?
the infraglottic cavity
*extends to the inferior end of the cricoid cartilage (below that is the tracheal rings)
What causes vibration of the true vocal folds? Is it the muscles?
Vibration of true vocal folds is not fascilitated by the muscles, but by air moving past the vocal folds. The air movement over them is what causes their vibration, while the muscles just determine the rate at which they vibrate.
What is this?
Large cartilagenous mass that is open posteriorly (filled with mucous linings)
thyroid cartilage
What are these?
Triangular shaped cartilages on top of the cricoid cartilages
arytenoids
What are two portions of the arytenoids? What is significant about each?
muscular process *has muscles attached to it that adduct or abduct the true vocal cords
vocal process *has a ligament to anterior border of the thyroid cartilage
What is this?
Most inferior ring of cartilage; forms a complete ring; taller posteriorly and shorter anteriorly
cricoid cartilage
What is the membrane between the cricoid and thyroid cartilages? What is significant about this membrane?
cricothyroid membrane; it has an elastic core and can enlarge or decrease in size depending on the position of the thyroid cartilage relative to the cricoid cartilage
What is this?
synovial joint that allows for tipping of the thyroid cartilage relative to the cricoid cartilage
cricothyroid joint
What axis of movement occurs at the cricothyroid joint?
transverse axis *allows the two cartilages to rock forward or backwards
There is a ligamentous structure coming off of the vocal process. What happens to this ligament if you rock the thyroid cartilage anteriorly? What happens to the ligament if you rock the thyroid cartilage posteriorly?
If you rock the thyroid cartilage forward, the ligament will get tight. If you rock it backwards, the ligament will get lax. *Allows for increase or decrease in tension of the vocal ligaments.
So what are the two synovial joints of the laryngeal cartilages?
- one between the cricoid and thyroid cartilages
2. one between the arytenoids and the cricoid
What is unique about the joint between the arytenoids and the cricoid cartilage?
it is a multiaxial joint; allows for rotation around the vertical axis and gliding movements medially and laterally *movement on both of these axes allows for adduction and abduction of the arytenoids
What does the thyrohyoid membrane connect? What passes through the hole in this membrane?!
hyoid bone and thyroid cartilage; internal branch of superior laryngeal nerve passes through
So what are the two extrinsic membranes of the larynx?
thyrohyoid membrane
cricothyroid membrane
What’s this?
Mucus lined membrane between epiglottis and artyenoid cartilages; helps keep food from going into the aditus (there are muscles associated w this membrane that act like a purse-string on the aditus and narrow it down)
quadrangular membrane
What does the superior free edge of the conus elasticus form? What does the inferior free edge of the quadrangular membrane form? What is the space between the two free edges?
true vocal fold and vocal ligament; false vocal fold; ventricle
What is this?
the vocal fold plus the slit (rima glottidis) between the two folds)
glottis
Synovial joints
Articulation between the inferior cornu of thyroid and the cricoid cartilage
Movement occurs around transverse axis
cricothyroid joint
Only laryngeal muscle not innervated by the recurrent
laryngeal nerve
cricothyroid muscle
What does the cricothyroid muscle do?
Rocker! When it contracts, it pulls the anterior border of the cricoid cartilage toward the thyroid cartilage, causing the arytenoids to move posteriorly and puts tension on the vocal ligaments which adducts them (brings them closer together!
Muscles that open the vocal ligaments (abduction) would have to be attached to what process of the arytenoid?
muscular process
What are the two movements of the arytenoids at the cricoarytenoid joint?
rotation on vertical axis
gliding movements on horizontal plane
*both of these actions abduct and adduct
What is the major ABDUCTOR of the vocal ligaments?
posterior cricoarytenoid
Where does the posterior cricoarytenoid come off of? Where does it attach? What does it do?
comes off the musclar process and attaches to the posterior midline of the cricoid cartilage; abducts
What does the lateral cricoarytenoid do? Where does it pass in relation to the cricoid cartilage?
ADDUCTS; passes anterior to cricoid cartilage
What does the transverse arytenoid muscle do? What does it pass between?
adducts; between the arytenoid cartilages
What does the oblique arytenoid muscle do?
pursestrings the aditus
What other muscle aids in pursestringing the aditus?
thyroepiglottic
What does the thyroarytenoid do? Where does it run?
from arytenoids to thyroid cartilage just under the true vocal folds; shortens vocal ligaments
What muscle is this?
Most important in helping to determine the pitch of your voice – selectively loosens or contracts small segments of the vocal ligament
vocalis
*ex: if your vocal ligament is very long, you’ll get a lower pitch, but when vocal ligament is shorter, higher pitch
Do you ever completely close off the larynx?
no, not even when muscles are purse-stringing
What muscles add and abduct on the vertical axis?
lateral (add) and posterior (ab) cricoarytenoid muscles
What muscles cause adduction and have more of a gliding movement?
transverse and oblique arytenoid muscles
What muscle is a tensor?
cricothyroid *tenses vocal ligament
What muscle is an abductor?
posterior cricoarytenoids
What muscles are adductors?
lateral arytenoids, oblique and transverse arytenoids
Which muscles relax?
thyroarytenoid and vocalis *less tension on vocal ligaments
Two muscles of laryngeal inlet?
oblique arytenoids
thyroepiglottic
What do the thyroepiglottic and aryepiglottic muscles to?
contract and pull in the walls of the aryepiglottic folds to decrease the size of the laryngeal aditus (purse-string) *have a protective function in keeping things out of the larynx
All of the vocal cord movers are adductors in some form except which?
posterior cricoarytenoid (abductor)
All muscles of the larynx are innervated by the recurrent laryngeal nerve except which?
cricothyroid (tensor) which is innervated by the external branch of the superior laryngeal
Which nerve is most susceptible during thyroid surgery?
recurrent laryngeal nerve *if you knock out this nerve, the only muscle that will remain functional is the cricothyroid
What are the two major nerves to the larynx?
superior laryngeal (internal and external branch) recurrent laryngeal
Discuss the motor innervation of the larynx
all intrinsic muscles by recurrent laryngeal, except cricothyroid (superior laryngeal)
Discuss the sensory innervation of the larynx
above vocal cords: superior laryngeal
below vocal cords: recurrent laryngeal
What is the cough reflex “in” and “out” on?
in on CN 10, out on 10 and phrenic
What are the two major vascular supplies to the larynx? Which artery enters the thyrohyoid membrane along with the internal branch of the superior laryngeal nerve?
superior laryngeal artery from the superior thyroid; inferior laryngeal artery from thyrocervical trunk
**superior laryngeal passes through the thyrohyoid membrane
What happens during swallowing?
elevate larynx
push tongue back
force epiglottis back a bit to cover trachea
bolus enters pharynx after passing laterally around epiglottis and into piriform recess
sequential constriction of pharyngeal constrictor muscles
passes through lowest pharyngeal constrictor (cricopharyngeus) and moves into esophagus
lower larynx
What is the major difference between the laryngeal and pharyngeal openings?
the pharyngeal opening is wider from lateral to medial; the larynx is longer from anterior to posterior
What is the nasal cavity originally continuous with?
the oral cavity
What bones grow in to separate the nasal cavity from the oral cavity?
palatine and maxillary bones
What are the four relevant prominences that must merge correctly in order to avoid facial malformations?
maxillary prominence; medial and lateral nasal prominences; frontonasal prominence *largest
The medial nasal prominences come together to form what midline structures?
philtrum of the upper lip
incisor portion of the upper jaw (medial and lateral incisors)
triangular primary palate up until the incisive canal
What separates the primary and secondary palate? What is anterior to this? What is posterior?
incisive canal; anterior to incisive canal is the primary palate and upper lip; posterior is the hard palate (secondary palate)
What results if any of these prominences fail to grow properly?
cleft lip and palate
Fairly common
More frequent in males
Maternal age dependent
cleft lip
Less common
More frequent in females
Not related to maternal age
isolated cleft palate
Any defect in the vicinity of the primary palate is due to failure of what two prominences to fuse?
medial nasal and maxillary prominences *cleft lip, cleft primary palate
What two structures fail to fuse in cleft secondary palate?
fusion failure of palatine shelves of maxillary prominence
What causes oblique clefts? What is unique about this type of defect?
fusion failure b/w maxillary and lateral nasal prominences **exposes the nasolacrimal duct
What’s this?
Two medial nasal prominences fail to fuse.
This will cause an incomplete formation of the neural tube, and is usually accompanied by mental retardation.
midline cleft *rare
What is the purpose of the three conchae of the lateral wall of the nasal cavity? What lies beneath each conchae? What lies over the conchae?
Conchae cause turbulent flow of air to slow it down – this allows warming, humidifying and cleansing of air; underneat each concha (superior, middle, inferior) is a meatus; mucous membranes lie over the conchae
What is the opening into the inferior nasal meatus?
nasolacrimal duct from the orbit
What are the openings into the middle nasal meatus?
maxillary and frontal sinus into hiatus semilunaris *also has a hole for the maxillary sinus to drain
ethmoid air cells drain into bulla
What is the opening above the superior concha
sphenoethmoidal recess for the sphenoid sinus
What is the most significant drainage in the nasal cavity?
drainage of the maxillary sinus, because most of the sinus lies inferior to its opening; the sinus has cilia that beat toward the opening to effectively drain it *when you have a maxillary sinus infection, may be easiest to drain while lying on one side w an ear on the pillow
What are the four paranasal sinuses?
maxillary
frontal
ethmoidal *on either side of nasal cavity
sphenoid *at very back of orbit
Are sinuses present in a newborn? When do they begin to form? When are they fully developed-ish?
no; 1 year; 21 years
What is the nerve supply to the lateral wall of the nasal cavity?
anterior ethmoidal nerves (terminal branches of nasociliary off of V1)
posterior nasal branches off palatine nerves or straight off the ganglion
What do the anterior ethmoidal nerves supply?
sensory innervation to lateral nasal cavity *do have some parasympathetic fibers to the mucous glands
How do the posterior nasal branches get into the pterygopalatine fossa?
From V2
What even synapses in the ganglion of the nasal cavity?
greater petrosal comes in carrying preganglionic parasympathetics to lacrimal gland; also preganglionic to mucous glands
What are the 3 portions of the medial wall of the nasal cavity?
perpendicular plate of ethmoid
vomer *posteriorly
septal cartilage *anterior/inferior
Three major arteries to the nasal cavity?
ehtmoidal arteries *from opthalmic artery
facial artery *inferiorly
sphenopalatine artery *continuation of maxillary artery
What thingy does the sphenopalatine artery pass thru to get into the pterygopalatine fossa?
pterygomaxillary fissure
Nerves to medial wall of nasal cavity (there are two)
anterior ethmoidal branch of V1
nasopalatine of V2 *main branch
What does the nasopalatine nerve end up doing?
continues inferiorly and enters the incisive canal - contributes a bit of innervation to the palate
What takes care of the skin of the face in the maxillary division?
infraorbital nerve
What three things are going INTO the pterygopalatine fossa?
- maxillary artery via pterygomaxillary fissure
- V2 via foramen rotundum
- sympathetics (deep petrosal) and parasympathetics (greater petrosal) via the pterygoid canal
What three things have to LEAVE the pterygopalatine fossa?
- Infraorbital nerve leaves via inferior orbital fissure *gives of posterior superior alveolar before entering the orbit, and then middle and anterior superior alveolar
- greater and lesser palatine nerves come off ganglion and enter palatine canal to reach the roof of the palate *greater palatine to hard palate and lesser palatine to soft palate
- nasopalatine via sphenopalatine to nasal cavity
What are the two little fibers coming from V2 to the ganglion?
- one brings sensory fibers in
2. the other brings postganglionic parasympathetics back to V2 to ultimately distribute to lacrimal gland
What does the deep petrosal nerve carry? Does it synapse in the ganglion?
sympathetics; no, already synapsed in cervical plexus
When parasympathetics jump back on the V2 from the ganglion, what nerves do they traverse to get to that dang lacrimal gland?
zygomaticofacial
zygomaticotemporal
then lacrimal of V1 (ZZTOP)
Alas, list the branches from the ganglion in the pterygopalatine fossa?
palatine nerves *inferiorly
lateral nasal branches *head anterior
nasopalatine *heads medially
What passes through the incisive canal?
nasopalatine nerve
descending palatine artery
What nerve passes through the sphenopalatine foramen w the sphenopalatine artery to travel medially?
nasopalatine nerve *ultimately dives inferior to pass thru the incisive canal
What “canal” do the greater and lesser palatine nerves pass through inferiorly?
palatine foramen
