Anatomy: Larynx Flashcards
what is enclosed in the pretracheal fascia
strap muscles
thyroid gland
trachea and larynx
oesphagus and pharynx
recurrent laryngeal nerves
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what is the function of the strap muscles
accessory muscles of breathing
where does your laryngopharynx range from
region of the pharynx from epiglottis to oesophagus
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where is the larynx found in relation to the laryngopharynx
anteriorly
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which vertebra is the larynx found between
C4 and C6
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which vertebral level is the hyoid bone at
C3
palpable structures in the neck
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laryngeal inlet
- connection between pharynx and larynx - opening into airway
how is the chance of aspiration reduced
raising of larynx towards the oesophagus
epiglottis moves posteriorly aiding the closure of the laryngeal inlet
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what are the nasal cavities separated by medially, and what is the composition of this structure
nasal septum - perpendicular plate of ethmoid bone, vomer, cartilage
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what is the larynx composed of
cartilage suspended from the hyoid bone
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functions of the larynx
maintain patency of URT
cartilage help prevent the entry of foreign bodies
vocal cords and cough reflex produce sound
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arytenoid cartilage
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cricoid pressure
pressing on the cricoid cartilage of the larynx compresses the oesphagus by pressing it against C6 vertebral body
this means the oesophagus is closed but the larynx/airway is open
prevents regurgitation and aspiration but allows ventilation
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what is another name for the laryngeal inlet
aditus
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where do the true vocal cords run between
vocal process of arytenoid cartilage to thyroid cartilage
movement impacts sound
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what are vocal cords
the free borders of mucosa covered connective tissue in the larynx
what do the false vocal chords run between
inferior border of quadrangular memebrane, runs from arytenoid cartilage to epiglottis
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what is the laryngeal pouch
fold between the vestivular and true vocal folds
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note: inferior magin forms the vestibular ligament covered by the vestibular fold
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quadrangular membrane
- between vestibular ligament (arytenoid cartilage) and epiglottis
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conus elasticus - attached to cricoid cartilage
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vallecula
space between epiglottis and tongue
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where is the laryngoscope places
vallecula
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aryepiglottic fold - superior border of the quadrangular membrane
what is the action of the intrinsic muscles of the larynx
control the shape of the rima glottidis and the length and tension of the vocal folds
attach between cartilages
what are all the intrinsic muscles of the larynx innervated by
CNX
impact of tension and relaxation of vocal cords
tension - increased pitch
relaxation - decresed pitch
impact of abduction and adduction of the vocal chords
abduction - louder
adduction - quieter
what is the tensor ligament of teh thyroid
cricothyroid - tenses vocal ligament and increases pitch
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what is this muscles, and what are its attachments
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cricothyroid - tensor muscle
anterolateral cricoid cartilage to inferior horn of thyroid cartilage
relaxor muscle of the larynx
thyroarytenoid muscles
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thyroarytenoid
from posterior thyroid to anterior arytenoid cartilage
adductor muscle of the larynx
Lateral crico-arytenoid muscles
and arytenoid muscles
make voice quieter by closing rima glottidis
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Lateral crico-arytenoid muscles
from muscular process of arytenoid to anterior cricoid cartilage
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thyroarytenoid - relaxor
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lateral crico arytenoid - adductor
arytenoid muscles
adduct/bring vocal ligaments together
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abductor muscles of the larynx
posterior crico-arytenoid muscles
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posterior crico-arytenoid muscles
attach from posterior cricoid cartilage to muscular process of arytenoid cartilage
which muscles are involved in controlled expiration
contraction of anterolateral abdominal wall muscles and internal intercostals
helps build pressure in respiratory tree inferior to larynx
pressure required depends on vocal task
how is phonation produced
stream of air across vocal chords
length/tension of VC indicates pitch of sound produced by vibration of the cords
degree of opening and shape of rima glottidis is also important
articulation of oral sounds
- Soft palate tenses (CN V3) and elevates (CN X) to close off entrance into nasopharynx
- Directs stream of air through oral cavity
- Sound interrupted by the tongue (CN XII) and the teeth/lips (CN VII) to produce most vowels and consonants in English language
articulation of nasal sounds
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- Soft palate tenses (CN V3) and descends (CN X) to close off entrance into oropharynx
- Directs stream of air through nasal cavities
- Produces one of three sounds: “m”, “n” or “ing” depending on position of tongue (CN XII), teeth and lips (CN VII).
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innervation of the intrinsic muscles
all apart from the cricothyroid are supplied by the inferior laryngeal nerve (CNX)
cricothyroid - external laryngeal nerve
what is the cricothyroid supplied by
motor from external laryngeal nerve
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what does the internal laryngeal nerve supply
mucosa above the folds
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what does the inferior laryngeal nerve supply
mucosa below the folds
all intrinsic muscles except cricothyroid
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how can CNX be clinically tested
pharynx: ask patient to swallow a small sip of water
larynx: ask patient to speak - voice hoarse?
ask patient to cough (this also requires functioning diaphragm, phrenic nerves and abdominal wall etc)
muscle: attachments and function
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OMOHYOID
inferior belly from scapula, superior belly attached to inferior by intermediate tendon which is attached to the clavicle
action: depresses hyoid bone
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omohyoid
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sternohyoid
muscle: attachments and function
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superiorly: thyrohyoid (depresses hyoid)
inferiorly: sternothyroid (depresses thyroid cartilage)