Anatomy: Larynx Flashcards
general features of larynx?
serves both respiratory and phonation fns.
- connects pharynx to trachea, acts to prevent passage of food materials into airways
where is larynx located?
anterior to CV3-CV6
laryngeal aditus
= “laryngeal inlet”
- superior opening from the pharynx
- triangular shaped
- directly above the laryngeal ventricles
vestibule
- the area making up the laryngeal aditus that is directly superior to the vestibular folds
vestibular “false” folds
folds located directly inferior of the vestibule, and superior to the laryngeal ventricle
laryngeal ventricle
area between vestibular and vocal folds
true vocal folds
- area underneath the laryngeal ventricle and superior to the infraglottic space
rima glottidis
= opening between the true vocal folds
- shape varies depending on position of vocal folds
- variation in tension and length of the vocal folds and width of rima produces changes in pitch of the voice
glottis
= rima glottidis plus vocal folds
infraglottic cavity
area below the true vocal folds
where is cricoid cartilage? anatomical relationships?
CV6
- site where carotid artery can be compressed against CV6
- junction of larynx and trachea
- jn. of pharynx and esophagus
tracheotomy
obstruction of the upper airway –> pucturing the larynx or trachea
- incision is made between cricoid cartilage and first tracheal cartilages
- incision can also be made between the cricoid and thyroid cartilages (through cricothyroid ligament)
thyroid cartilage
lies anterior to CV4,5
- features 2 side laminae that are fused anteriorly and remain open posteriorly
- superior horn: attached to hyoid bone by lateral thyrohyoid ligament
- inferior horn: articulates with cricoid cartilage
- laryngeal prominence = “adams apple”
- superior thyroid notch = superior to laryngeal prominence
- oblique line
cricoid cartilage
- lies anterior to CV6
- it is an IMMOVABLE ring that is attached via membrane to first tracheal cartilage
- anterior arch
- posterior lamina
- facets for articulation with arytenoid and thyroid cartilages
arytenoid cartilage
- x2 of them
- lie perched atop posterior portion of cricoid cartilage
- apex: attaches to aryepiglottic fold
- vocal processes: attach to vocal ligament
- muscular processes: attach to posterior and lateral cricoarytenoid mm.
epiglottic cartilage
x1
- leaf shaped, elastic cartilage that is situated posterior to the root of the tongue
- broad superior end is free
- inferior end attached to thyroid cartilage
- muscles of pharynx pull the thyroid cartilage against the epiglottis during swallowing to prevent food from moving into the larynx
- Ligaments: thyroepiglottic, hyoepiglottic, aryepiglottic, glossoepiglottic ligaments
corniculate cartilage
lies atop the apex of arytenoid cartilages
cuneiform cartilage
lies within aryepiglottic folds
what is the only fixed cartilage?
cricoid cartilage
- all others will move on this
vestibular fold
see from ppt.
quadrangular ligament? what two folds does it form? where does it attach?
intrinsic ligament
- attaches anteriorly to thyroid/epiglottic cartilages, attaches posteriorly to arytenoid cartilage.
- forms vestibular ligaments: covered with mucosa = vestibular fold
- forms aryepiglottic ligament: covered with mucosa = aryepiglottic fold
cricovocal ligament? attaches? what are its thickened regions?
aka “conus elasticus”
- attaches cricoid cartilage to thyroid/arytenoid cartilages
- contains thickened regions:
1. median cricothyroid ligament
2. lateral cricothyroid ligament
3. vocal ligament = vocal fold when covered with mucosa (extends from internal surface of thyrooid lamina to vocal process of arytenoid)
Vocal folds
formed from mucosa overlying the vocal ligament and vocalis muscle
- vocal ligament = innermost portion of cricovocal ligament; extends from thyroid cartilage to vocal process of arytenoid cartilage
- vocalis muscle = innermost portion of thyroarytenoid muscle
- vocal ligaments change tension/length in order to control pitch of voice
Vestibular folds
formed from mucosa overlying vestibular ligament
- covered with highly vascularized mucosa; contains many mucus secreting glands
vestibular fold = ?
mucosa + vestibular ligament (lower part of quad membrane)
vocal fold = ?
mucosa + vocal ligament (upper part of cricovocal membrane)
ventricle = ?
sacculation created in wall of larynx between quadrangular membrane and cricovocal membrane
cricothyroid joint
articulation between cricoid cartilage and inferior horn of thyroid
- synovial - gliding movment
- allows thyroid to glide on cricoid in order to change vocal cord length
- ** allows for pitch of speech to be changed
cricoarytenoid joint
articulation b/w cricoid and arytenoid cartilage
- synovial- gliding and rotational mvmts
- allows arytenoid to rotate and glide towards one another
what are the primary movments of the laryngeal cartilages?
- rotation of arytenoids to abduct/adduct vocal ligaments
- gliding of arytenoids to adduct vocal ligaments and close rima glottis
- rotation of thyroid cartilage to increase and decrease length and tension of vocal ligaments
rotation of arytenoid cartilages?
- rotation of arytenoid to abduct (posterior cricoarytenoid) and adduct (lateral cricoarytenoid) vocal ligaments
gliding of arytenoid cartilages?
adduct vocal ligaments (close rimar glottitis) via the (transverse and oblique artenoids)
rotating of thyroid cartilage on cricothyroid joint?
increased tension of vocal ligaments (cricothyroid m)
decreased tension of vocal ligaments (thyroarytenoid m.)
cricothyroid muscle
- Attaches to cricoid anteriorly
- Inserts into thyroid posteriorly
- Tilts thyroid forward to elongate and tense vocal ligaments.
- Innervation = External laryngeal branch of superior laryngeal nn (**only laryngeal muscle not innervated by recurrent laryngeal n)
transverse and oblique arytenoids
- Extend from arytenoid to arytenoid
- Adduct arytenoid cartilages
- Close laryngeal inlet by approximating the arytenoid cartilages
- Innervation = recurrent laryngeal n
thyroarytenoid mm. (“vocalis”)
rotates thyroid cartilage back to shorten and loose the vocal ligament
posterior cricoarytenoid
- Attach to posterior cricoid
- Insert at muscular process of arytenoid
- Abduct vocal folds
- Innervation – recurrent laryngeal n
(opens rima glottidis)
lateral cricoarytenoid
- Attach to lateral cricoid
- Insert at muscular process of arytenoid
- Adduct vocal folds
- Innervation – recurrent laryngeal n
(closes rima glottidis)
vocalis muscle
innermost portion of thyroarytenoid m.
lateral to vocal ligament
- Attach to thyroid anteriorly
- Insert along anterior surface of arytenoid
- Tilt thyroid posteriorly to shorten vocal ligaments
- Vocalis mm fine tunes tension on vocal ligament
- Innervation – recurrent laryngeal n
what are all but one of the vocal muscles innervated by? which one is different?
recurrent laryngeal n (becomes inferior laryngeal n. in larynx)
- cricothyroid is the ONLY muscle innervated by external branch of superior laryngeal n.
internal branch of superior laryngeal n innervation?
CN X - pierces thyrohyoid membrane - provides: GVE-P and VGA proximal to true vocal folds SVA to epiglottic region of tongue
what does external laryngeal branch of superior laryngeal n. provide?
CN X
SVE to cricothyroid muscle
cough reflex
mediated by CN X in order to prevent food from entering airways
- when food gets in larynx, the superior laryngeal n. is stimulated (GVA) and causes contraction of laryngeal muscles which close the larynx.
- Vagus n. will stimulate a cough in order to force air out of larynx
- injury to superior laryngeal n. will ablate this fn (can be due to anesthesia of laryngeal mucosa
“in by X, out by X”
superior laryngeal n. lesion
will result in loss of cough reflex, due to loss of sensation to supraglottic region
- the cricothyroid m. will also be paralyzed which often causes a monotonous voice
superior laryngeal n. block
administered when inserting and endotracheal tube. the needle is inserted halfway between the hyoid and superior border of thyroid. neede pierces the thyrohyoid membrane
lesion of recurrent laryngeal n.
- can occur with neck or thoracic damage/surgery
- the left recurrent laryngeal n. branches in the thorax (can be damaged via aortic aneurysms, tumors, enlarged lymph nodes in thorax)
unilateral = raspy voice (hoarseness)
bilateral = complete voice loss (aphonia)
inferior laryngeal n.
= recurrent laryngeal n (CN X)
- enters larynx by passing inferior to inferior constrictor m.
- provides:
1. GVE-P and GVA distal to true vocal folds (infraglottic region)
2. SVE to all muscles of larynx, except cricothyroid
3 arterial supplies to larynx?
- superior laryngeal a: branch of superior thyroid artery, pierces thyrohyoid membrane, supplies larynx above true vocal folds
- cricothyroid artery: branch of superior thyroid artery; supplies cricothyroid muscle
- inferior laryngeal a: branch of inferior thyroid artery, supplies larynx below true vocal folds
venous supply of larynx?
superior laryngeal vein –> IJV
inferior laryngeal vein –> left brachiocephalic v.
lymphatic drainage of larynx?
- proximal (above) true vocal folds –> superior deep cervical lymph nodes
- distal/below true vocal folds –> inferior deep cervical lymph nodes
