Head and Neck Session 12 Flashcards
what structure does the isthmus of the thyroid gland lie just below?
the cricoid cartilage
blood vessels to and from thyroid gland?
superior thyroid artery from ECA which forms A and P branches at upper poles of L and R lobes
inferior thyroid artery from thyrocervical trunk off subclavian artery, which also supplies blood to upper 1/3 of oesophagus
superior, middle and inferior thyroid veins which are tributaries of IJV which drains into the subclavian vein to enter SVC
to what cartilages does the cricothyroid muscle attach to?
thyroid and cricoid cartilages (above and below respectively)
where are the piriform fossae of the laryngopharynx formed?
at the laryngeal inlet (on each side)
what is the pharyngeal muscle layer covered by internally?
pharyngobasilar fascia, which is covered by the mucous membrane
what does the laryngopharynx lie posterior to?
laryngeal inlet (and larynx)
what is the larynx located between?
the hyoid bone above (C3) and the trachea below
so lies between C4 and C6
structures forming framework of larynx?
epiglottis, thyroid and cricoid cartilages=unpaired
paired arytenoid cartilages, cuneiform and corniculate
how is the larynx attached to the hyoid bone above?
by the thyrohyoid membrane and the thyrohyoid muscle- an infrahyoid muscle
other infrahyoids= sternothyroid, sternohyoid, omohyoid
attachments of epiglottis?
anter= body of hyoid= from 2nd and 3rd pharyngeal arch cartilages
poster= back of thyroid cartilage
sides connected to arytenoids by aryepiglottic folds- run bwards to form margins of aditus of larynx
what is the laryngeal prominence?
where the 2 lateral plates of the thyroid cartilage meet in the midline in a prominent V= Adam’s apple
attachment of cricoid cartilage inferiorly?
to trachea by cricotracheal membrane= connects all cartilages and its upper edge is slightly thickened to form vocal ligament.
anteriorly thickened as cricothyroid ligaments= easily felt and used in emergency for cricothyroid puncture for laryngeal obstruction
at what vertebral level is the pharynx continuous with the oesophagus?
C6
what is the uvula?
cone-shaped process of the soft palate-lies posterior to hard palate
what cartilage does the cricoid cartilage attach to inferiorly?
the 1st cartilaginous ring of the trachea ( an incomplete cartilage posteriorly where trachealis muscle located, but cricoid is a complete cartilage)
what does the criocthyroid muscle do to the VCs?
it tenses them
what does the posterior cricoarytenoid muscle on each side do?
rotates the arytenoids outwards, so separating the VCs
innervation of mucosa above VCs in larynx?
internal laryngeal nerve from superior laryngeal
innervation of mucosa below VCs?
recurrent laryngeal nerve
why do the VCs not become oedematous with URTIs?
absence of intervening SM between mucosa and vocal ligament so no fluid can collect underneath the VCs
effect of superior laryngeal nerve damage on phonation?
some wkness results as loss of tightening effect of cricothyroid muscle on VC as innervated by this nerve
what may be the solution to bilateral recurrent laryngeal nerve damage?
tracheotomy- can open a direct airway with trachea by creating a hole in anterior part of neck
position of VC if RLN damaged?
neutral/paramedian position between abduction and adduction
what is a pharyngeal pouch?
a posterior herniation of pharyngeal mucosa= true diverticulum
occurs through Killian’s dehiscence- between inferior constrictor and cricopharyngeus
which membrane can be perforated in an emergency to gain access to the airway below the level of the vocal folds of the larynx?
cricothyroid (cricovocal) membrane, which is palpable in midline, allows access to infraglottic space of airway
what is the vocal ligament?
the upper, free, thickened margin of the cricothyroid membrane running between the deep surface of angle of thyroid anteriorly and arytenoid cartilages (from vocal processes) posteriorly, and is found within the VCs
sensory innervation of laryngeal cavity above and below vocal folds (cords)?
above= superior laryngeal nerve below= recurrent laryngeal nerve