larynx: clinical Flashcards
how do the vocal cords appear when seen in laryngoscopy? why?
pearly white avascular appearance
the mucosa is firmly attached to the vocal ligament without any intervening submucosa
do the vocal cords become oedematous during upper respiratory tract infections? why?
no
absence of intervening submucosa = no fluid can accumulate underneath the vocal cords
what will damage to recurrent laryngeal nerve result in? why?
recurrent laryngeal nerve innervates muscles moving vocal cords
damage = paralysis to vocal cords + hoarseness of voice
how do patients with UNIlateral recurrent laryngeal nerve palsy present?
initially: voice weak, paralysed vocal cords can’t ADduct fully to meet normal unaffected vocal cord on the other side
within a few weeks: contralateral fold (chord) crosses the midline to meet (paralysed) vocal cord and compensates
how do patients with bilateral paralysis of the vocal chords present?
causes voice to be almost absent
vocal chords take up more ADducted position than normal resting position
why do patients with bilateral paralysis of vocal chords result in stridor?
vocal cords cannot be ABducted for respiration (can’t pull vocal chords apart, so rima glottis becomes severely reduced)
high-pitched, turbulent air flow in larynx / LOWER down in bronchial tree
usually inspiratory, but can be expiratory or biphasic
both vocal cords assume PARAMEDIAN position
with progression of recurrent laryngeal nerve lesion, which movement is loss first?
ABduction of vocal ligaments lost before ADduction
(harder to pull vocal ligaments apart by Posterior cricoarytenoid muscles, adduction by lateral cricoarytenoid)
both innervated by recurrent laryngeal branch of vagus
following surgery, does adduction or abduction of vocal chords return first?
ADduction before abduction
what does paralysis of superior laryngeal nerve result in?
anaesthesia of superior laryngeal mucosa and cricothyroid muscle
loss of protective mechanism designed to keep foreign bodies out of larynx and produces a monotonous voice
why does a superior laryngeal nerve palsy cause monotonous voice?
palsy changes the pitch of the voice and causes an inability to make explosive sounds due to paralysis of the cricothyroid muscle
how do surgeons avoid injury to the external branch of superior laryngeal nerve during thyroidectomy?
the superior laryngeal artery is ligated superior to the gland where it is not closely related to the nerve
what is the piriform fossa a common site for?
where foreign bodies entering the pharynx can become lodged
how can the piriform fossa be viewed and what does it look like / act?
larynx tilting up and epiglottis down
fossa is pear shaped and acts as a funnel
what happens if sharp objects pierce the mucous membrane of piriform fossa (lateral to laryngeal inlet)?
nerve damage can occur:
superior laryngeal nerve (especially internal laryngeal branch - sensory to supraglottic)
what is the epiglottic vallecula?
a depression from folds (vallecula) just behind the root of the tongue, but in front of epiglottis
(These depressions serve as “spit traps”; saliva is temporarily held in the valleculae to prevent initiation of the swallowing reflex)