Anatomy of the larynx and hyoid Flashcards
What shape is the hyoid bone?
where is it found?
what is its function?
anatomically made of 3 parts. What are they?
- U shaped bone
- located in the anterior neck roughly at the base of the mandible. C3
- generally acts as an attachment site for the anterior neck muscles
3 parts of the hyoid bone;
- body
- greater horn
- lesser horn
label the hyoid bone
A- greater horn
B- lesser horn
C- body
Muscular attachments of the hyoid
- oral cavity and pharynx (3)
- suprahyoid (4)
- infrahyoid (3)
Muscular attachments of the hyoid
- oral cavity and pharynx
- middle pharyngeal constrictor
- hyoglossus
- genioglossus
- suprahyoid (4)
- digastric
- stylohyoid
- geniohyoid
- mylohyoid
- infrahyoid (3)
- thyrhyoid
- omohyoid
- sternohyoid
Which 3 ligaments attach to the hyoid bone?
ligaments that attach to the hyoid bone
- stylohyoid ligament- from styloid process of temporal bone to the lesser horn of the hyoid bone
- thyrohyoid ligament- originates from the upper border of the thyroid cartilage and attaches to the posterior surface of the hyoid bone and greater horns
- hyoepiglotic ligament- connects hyoid bone to the anterior aspect of the epiglottis
The larynx
also known as?
3 important fucntions:
what is it primarily made up out of? what holds thes elements together?
which muscles move components for above purposes?
the voice box
important functions:
- phonation
- cough reflex
- protection of lower resp tract (from reflux and bolus)
- The larynx if primarily made up of cartilage and is held together by ligamaments
- internally laryngeal muscles move components of the larynx
Anatomical posiiton and relations of the larynx
- which spine levels does it span between
- suspended from what
- covered anteriorly by
- is posterior to what structure
- continuous inferiorly to what
- opens superiorly in to what
- covered laterally by what
- spans between C3- C6
- suspended from the hyoid bone
- covered anteriorly by infrahyoid muscles
- posterior is the oesophagus
- continues inferiorly into the trachea
- opens superiorly into the laryngeal part of the pharynx
- covered laterally by lobes of the thyroid gland
structure?
anatomically the internal cavity of it can be split into 3 sections, what are they?
formed from a cartilaginous skeleton held together by ligaments and membranes
the 3 sections of the internal cavity are:
- supraglottis- formed from the inferior surface of the epiglottis and vestibular folds
- glottis- vocal chords. The opening of the vocal chords is known a the rima glottidis
- subglottis- inf border of the glottis to the inf border of the cricoid cartilage
arterial supply to the larynx
venous drainage
innervation
larynx
-
Arterial-
- superior laryngeal artery- branch of the superior thyroid artery (of ECA). follows the internal branch of the superior laryngeal nerve to the larynx
- inferior laryngeal artery- branch of the inferior thyroid artery (branch of the thyrocervical trunk) follows the recurrent laryngeal nerve to the larynx
- Venous- superior and inferior laryngeal veins
-
Innervation- receives both motor and sensory innervation from branches of the vagus
- Recurrent laryngeal nerve- sensory info to infraglottis and motor innervation to the muscles of the larynx (exc. cricothyroid)
- superior laryngeal nerve- internal branch sensory to supraglottis, external motor to cricothyroid
vocal cord paralysis
which nerve is responsible for phonation?
presentation of unilateal paresis?
bilateral?
which is more common?
causes?
paired recurrent laryngeal nerves
- Unilateral vocal cord paralysis-presents with dysphonia (hoarseness), characterised as a breathy, weak voice due to air leaking through the glottic gap as one vocal cord is unable to adduct fully. Patients may also complain of dysphagia or choking as glottic incompetence increases the risk of aspiration.
- Bilateral- dyspnoea if the paralysed cords rest close to the midline, reducing the glottic area available for air movement.
unilateral is more common as only one nerve affected
causes:
- apical lung tumour
- thyroid cancer
- iatrogenic- e.g, thryoidectomy
- aortic aneurysm
- cervical lymphadenopathy
how many cartilages are found in the thyroid?
how many are paired and how many are unpaired?
9
3 are unpaired and 6 are paired
what are the 3 unpaired cartilages that make up the larynx?
thyroid cartilage
- easily visible in men, large prominent structure
- composed of 2 sheets (laminae) which join anterioly to form the laryngeal prominence (Adam’s apple)
- posterior border of each sheet project to form superior and inferior horns (AKA cornu)
- superior horns are conencted to the hyoid bone via the lateral thyrohyoid ligament
cricoid cartilage
- complete ring of cartilage consisting of a broad sheet posteriorly and a narrow sheet anteriorly
- this is the only complete ring in the larynx
- inferior border is at C6
epiglottis
- leaf shaped plate of elastic cartilage which marks the entrance to the larynx
- it’s stalk attached tothe back of the anterior thyroid cartilage
- During swallowing- the epiglottis flattens and moves posterioly to close off the larynx and prevent aspiration
paired cartilages of the larynx
how many of them are there? where can they be found?
name the 3 paired cartilages
there are 3 paired cartilages
they are situated bilaterally in the larynx
- arytenoid cartilage
- corniculate cartilage
- cuneiform cartilage
arytenoid cartilage
what shape are they
what do they sit on top of
provides key attachments for (5)
pyramidal shape
sit on top of the cartilage
key attachments:
- apex- corniculate cartilage
- base- superior border of the cricoid cartilage
- vocal process- provides attachment for the vocal ligament
- muscular process- posterior and lateral cricoarytenoid muscles
corniculate cartilage
cuneiform cartilage
corniculate cartilage- very very small
cuneiform cartilage- can be found within the epigastric folds
What is the function of the ligaments in the larynx?
what is the funtion of the folds in the larynx?
what is the function of extrinsic and intrinsic ligaments?
- the ligaments support the cartilaginous skeleton of the larynx
- the folds are involved in ariway protection and phonation
- extrinsic ligaments- attach the larynx to external structures
- intrinsic ligaments- hold the cartilages of the larynx together as one functional unit internally
