Larynx Flashcards
What is the larynx and where is it connected? (3)
- Composed of 9 cartilages connected by ligaments and membranes and contains vocal folds
- Located in the anterior neck at the level of the bodies of C3-C6 vertebrae
- Connects the inferior part of the pharynx with the trachea
What are the functions of the larynx? (3)
o Valve routing air and food
- Upward and forward movements facilitate the closing of the laryngeal inlet and opening of the oesophagus
o Voice production
- Vocal ligament and intrinsic muscles
o Airway patency
- Serves as the sphincter of the lower respiratory tract
Laryngeal Skeleton
* Consists of 3 single cartilages:
(thyroid, cricoid and epiglottic),
3 paired cartilages (arytenoid, corniculate and cuneiform), extrinsic and intrinsic membranes
What are the 1. Thyroid cartilages? (2)
o Largest of the cartilages
o Superior border lies opposite C4 vertebra
- Thyroid cartilage:
o Laminae:
- Two plate-like regions of the inferior 2/3 of the cartilage that fuse anteriorly in the median plane to form the laryngeal prominence (Adam’s apple)
- Thyroid cartilage:
o Superior thyroid notch:
- V-shape superior to the laryngeal prominence where the laminae diverge
- Thyroid cartilage:
o Inferior thyroid notch:
- Shallow indentation in the middle of the inferior border of the cartilage
- Thyroid cartilage:
o Superior and inferior horns:
- Superior and inferior projections of the posterior border of each lamina
- Thyroid cartilage:
o Median thyroid ligament:
- Thick part in the median part of the thyrohyoid membrane
- Thyroid cartilage:
o Lateral thyrohyoid ligaments:
- Thick parts in the lateral parts of the thyrohyoid membrane
- Thyroid cartilage:
o Cricothyroid joints: (2)
- Articulation between the inferior horns of the thyroid cartilage and the lateral surfaces of the cricoid cartilage
- Movements- rotation and gliding of the thyroid cartilage ® change in length of vocal folds
What is the 2. Cricoid cartilage? (2)
o Smaller than thyroid cartilage but thicker and stronger
o Cricoid is the only complete ring of cartilage to encircle any part of the airway
- Cricoid cartilage
Lamina: (3)
- Posterior part of cricoid
- Depressions for attachment of posterior
cricoarytenoids - Vertical ridge for attachment to oesophagus
- Cricoid cartilage
o Arch:
- Anterior part of cricoid
- Cricoid cartilage
o Median cricothyroid ligament:
- Attachment of the cricoid to the inferior margin of the thyroid cartilage
What is the 3. Epiglottis? (5)
o Consists of elastic cartilage for flexibility
o Heart-shaped and covered with mucous membrane
o Located posterior to the root of the tongue and the hyoid and anterior to the laryngeal inlet
o Forms the superior part of the anterior wall and the superior margin of the inlet
o Has a broad, free superior end
o Stalk of the epiglottis:
- Attached to the angle formed by the thyroid laminae
What are the Extrinsic laryngeal membranes? (4)
What is the 1. Arytenoid (paired cartilages)? (4)
o Paired, 3-sided pyramidal cartilages
o Articulate with the lateral parts of the superior border of the cricoid cartilage lamina
o Apex superiorly, vocal process anteriorly and muscular process laterally
o Apex- bears the corniculate cartilage and attaches to the aryepiglottic fold
- Arytenoid
What is the o Vocal process?
o Vocal process- provides the posterior attachment for the vocal ligament
- Arytenoid
What is the muscular process?
o Muscular process- lever to which the posterior and lateral cricoarytenoid muscles are attached
What are cricoarytenoid joints?
-Located between the bases of the arytenoid cartilages and the superolateral surfaces of the lamina of the cricoid cartilage
What do the Cricoarytenoid joints permit? (3)
- Permit the arytenoid cartilages
- to slide toward or away from one another
- to tilt anteriorly and posteriorly
- to rotate
What is the 2. Corniculate? (2)
o Appears as a small nodule in the posterior part of the aryepiglottic fold
o Attaches to the apex of the arytenoid cartilage
What is the 3. Cuneiform? (2)
o Appears as a small nodule in the posterior part of the aryepiglottic fold
o Does not directly attach to other cartilages
What are Intrinsic laryngeal membranes? (2)
- Conus elasticus (cricovocal membrane)
- Quadrangular membrane
Fibroelastic membrane of the larynx
1. Conus elasticus (cricovocal membrane):
* Inferior attachment:
o Arch of the cricoid cartilage
Fibroelastic membrane of the larynx
1. Conus elasticus (cricovocal membrane):
* Superior attachments: (2)
o Anterior- thyroid cartilage
o Posterior- vocal processes of arytenoids
- Conus elasticus (cricovocal membrane)
* Vocal ligament-
- Vocal ligament- thickened medial part of membrane under the vocal fold
- Conus elasticus (cricovocal membrane)
* Median cricothyroid ligament-
- Median cricothyroid ligament- anterior thickening in the midline of the membrane
What is the 2. Quadrangular membrane? (2)
- Runs between the lateral margin of the epiglottis and the anterolateral surface of the arytenoid cartilage
- Attached to the corniculate cartilage
- Vestibular ligament-
- Vestibular ligament- thickened free lower margin under the vestibular fold
- Vestibular ligament-
o Attached posteriorly to…
o Attached anteriorly to…
o Attached posteriorly to the anterolateral surface of the arytenoid
o Attached anteriorly to the thyroid angle just superior to the vocal ligament
Cavity of the larynx:
* Superior aperture: (2)
o Laryngeal inlet
o Opens into the anterior aspect of the pharynx below the posterior tongue
Cavity of the larynx:
What are the boundaries of the superior aperture? (3)
- Anteriorly- mucosa covering the superior margin of the epiglottis
- Laterally- aryepiglottic folds
- Posteriorly- interarytenoid notch in the midline
Cavity of the larynx:
* Inferior aperture: (3)
o Continuous with the trachea
o Completely encircled by the cricoid cartilage
o Always open (unlike superior aperture which can be closed by the epiglottis)
What are the regions of the cavity? (3)
- Vestibule
o Upper chamber
o Between the laryngeal inlet and the vestibular folds (membrane enclosing vestibular ligaments) - Middle part
o Between the vestibular folds above and vocal folds (membrane enclosing vocal ligaments) below - Infraglottic space
o Inferior chamber
o Between the vocal folds and inferior aperture
- Laryngeal ventricles and saccules:
o Mucosa of the middle cavity bulges ______
o Between the vestibular and _____ ligaments
laterally
vocal
What is the o Laryngeal ventricle?
o Laryngeal ventricle- trough shaped space produced by mucosal bulging
What is the o Laryngeal saccule?
o Laryngeal saccule- tubular extension of each ventricle
- Projects antero-superiorly between vestibular fold and thyroid cartilage
- Contains numerous mucous glands to lubricate the vocal folds
What is the * Rima vestibuli? (2)
o Triangular opening between the adjacent vestibular folds
o Apex is anterior and base is formed by posterior wall of laryngeal cavity
What is the Rima glottidis? (3)
o Inferior to the rima vestibuli and narrower
o Triangular opening between the adjacent vocal folds
o Base of the triangle is formed by interarytenoid fold (mucosa covering interarytenoid notch)
- Both rima glottidis and rima vestibuli can be opened and closed by movement of _______.
cartilages
What are the Intrinsic Laryngeal Muscles? (3)
- Adjust the tension in the vocal ligaments to open and close the rima glottidis
- Control the inner dimensions of the vestibule and close the rima vestibuli
- Facilitate closing of the laryngeal inlet
What are the Intrinsic Laryngeal Muscles? (7)
Intrinsic Laryngeal Muscles:
Cricothyroid
Origin:
Insertion:
Main Action:
Innervation:
Intrinsic Laryngeal Muscles:
Posterior crico-arytenoid
Origin:
Insertion:
Main Action:
Innervation:
- Posterior surface of lamina of cricoid
- Vocal process of arytenoid
- Abduction and external rotation of arytenoid (opens rima glottidis)
- Recurrent laryngeal br. of vagus n.
Intrinsic Laryngeal Muscles:
Lateral crico-arytenoid
Origin:
Insertion:
Main Action:
Innervation:
- Superior surface of arch of cricoid
- Vocal process of arytenoid
- Internal rotation of arytenoid (closes rima glottidis)
- Recurrent laryngeal br. of vagus n.
Intrinsic Laryngeal Muscles:
Transverse arytenoid
Origin:
Insertion:
Main Action:
Innervation:
- Posterior surface of arytenoid
- Posterior surface of opposite arytenoid
- Adduction of arytenoids
- Recurrent laryngeal br. of vagus n.
Intrinsic Laryngeal Muscles:
Oblique arytenoid
Origin:
Insertion:
Main Action:
Innervation:
- Muscular process of arytenoid
- Apex of opposite arytenoid
Aryepiglottic part- extends into aryepiglottic fold - Sphincter of laryngeal inlet
- Recurrent laryngeal br. of vagus n.
Intrinsic Laryngeal Muscles:
Thyroarytenoid
Origin:
Insertion:
Main Action:
Innervation:
- Thyroid angle and cricothyroid ligament
- Anterolateral part of arytenoid
Lateral margin of epiglottis - Sphincter of vestibule and laryngeal inlet
Relaxes vocal ligament - Recurrent laryngeal br. of vagus n.
Intrinsic Laryngeal Muscles:
Vocalis
Origin:
Insertion:
Main Action:
Innervation:
- Vocal process of arytenoid
- Ipsilateral vocal ligament
Thyroid angle - Adjusts tension (minutely) in vocal folds
- Recurrent laryngeal br. of vagus n.
Intrinsic Laryngeal Muscles:
* Abductors-
* Adductors-
* Sphinters-
* Tensors-
* Relaxers-
- Abductors- posterior crico-arytenoids
- Adductors- lateral crico-arytenoids, transverse and oblique arytenoids
- Sphinters- adductors and aryepiglottic part of oblique arytenoids
- Tensors- cricothyroid muscles
- Relaxers- thyroarytenoid muscles
What are the Arteries of the larynx? (2)
- Superior laryngeal artery
- Inferior laryngeal artery
What is the Superior laryngeal artery? (4)
o Branch of superior thyroid artery
o Pierces thyrohyoid membrane
o Supplies superior internal surface of larynx
o Accompanied by superior laryngeal nerve
What are the veins of the larynx? (2)
- Superior laryngeal vein
o To superior thyroid v. to IJV - Inferior laryngeal vein
o To inferior thyroid v. to left brachiocephalic v.
Lymphatic drainage of the larynx
* Above vocal folds:
o Superior deep cervical lymph nodes
Lymphatic drainage of the larynx
* Below vocal folds:
o Pretracheal or paratracheal lymph nodes to inferior deep cervical lymph nodes
Innervation of the larynx:
