3.4 Anatomy of the larynx Flashcards
The larynx (voice box) is located in the anterior neck at the levels of C3 – C6:
• Functions: phonation (voice production), cough reflex, protection of lower respiratory tract (particularly during swallowing → epiglottis seals it off temporarily)
• Composed of a cartilaginous skeleton connected by membranes and ligaments (with the laryngeal muscles involved in phonation and breathing)
Locations of….
- Supraglottis: ________________
- Glottis: Vocal cords (1cm below supraglottis)
- Subglottis: Inferior border of glottis to __________________
Inferior surface of epiglottis to vestibular folds (false vocal cords);
inferior border of cricoid cartilage
What are the relations of the pharynx?
- superior: opens into laryngopharynx
- inferior: continues with trachea
- lateral: lobes of thyroid gland, CCA, IJV
- anterior: infrahyoid muscles
Epiglottis
- Leaf-shaped elastic cartilage (entrance to larynx):
• Stalk attached to __________
- Moves forward towards arytenoid during swallowing to close larynx (prevents aspiration)
back of thyroid cartilage;
thyroid cartilage: 2 lamellae joined anteriorly to form laryngeal prominence (Adam’s apple):
• Posterior border projects superiorly as superior horn (articulates with______________); inferiorly as inferior horn (contact with ________________)
Forms most of the ______________ → protects the vocal folds
hyoid bone;
cricoid cartilage;
anterior laryngeal wall
Cricoid: Ring of hyaline cartilage (forms a broad sheet posteriorly and narrow arch anteriorly):
• Completely encircles the airway (marks ____________________)
• Articulates with _________________ posteriorly
- Provides attachment for inferior horns of thyroid cartilage
inferior border of larynx at C6;
paired arytenoid cartilages
Arytenoid: Pyramid-shaped cartilage sitting on cricoid cartilage:
• Apex articulates with __________________
• Base articulates with superior border of cricoid cartilage (forms cricoarytenoid joints)
• Vocal process: for vocal ligaments
• Muscular process: for ________________
- Allows tensing and relaxing of vocal folds
corniculate cartilages ;
posterior and lateral cricoarytenoid muscles
Corniculate
- Minor cartilaginous structures which articulate with the _______________;
- Prolongs arytenoid cartilages posteriorly and medially
Cuneiform
- No direct attachment
- Strengthens the vocal folds
apices of the arytenoid cartilages
[Extrinsic laryngeal ligaments and membranes]
Thyrohyoid membrane: Links larynx to hyoid bone (spans between superior aspect of thyroid cartilage and hyoid bone):
• Laterally pierced by _______________
• Median thyrohyoid ligament: thickened midline part
• Lateral thyrohyoid ligaments: posterolateral
Hyo-epiglottic ligament: Connects hyoid bone to ________________
Median cricothyroid ligament: Connects thyroid and cricoid cartilages in the midline
Cricotracheal ligament: Connects cricoid cartilage to _________________
superior laryngeal vessels and internal laryngeal nerve;
anterior aspect of epiglottis;
first tracheal cartilage
[Intrinsic laryngeal ligaments and membranes]
Cricothyroid membrane: Begins at cricoid cartilage and extends superiorly to the unattached upper margin (forms ___________):
• Attached anteriorly to thyroid cartilage
Quadrangular membrane: Spans between ____________________ and ____________________:
• Possesses free upper and lower margins (lower margin thickened to form ____________
vocal ligament;
anterolateral arytenoid cartilages and lateral aspect of epiglottis;
vestibular ligament)
LARYNGEAL FOLDS
The laryngeal folds consist of the vocal folds (true vocal chords) and vestibular folds (false vocal chords), and are involved in airway protection and phonation:
• Ventricle located between the vocal folds and vestibular folds help to moisturise the vocal cords
Vocal fold: Control ____________________
• Relatively avascular (appears white)
• ___________: space between vocal folds
Vestibular fold: Lies superior to true vocal chords; consisting of vestibular ligament covered by __________
• Fixed folds which provide protection for the larynx
Singer’s nodule: occurs due to using the vocal cords too hard –> results in hoarseness of voice
- Treatment: ____________ (using laryngoscope to laser away the nodule –> removes the hoarseness)
muscles of phonation (relax, tense, adduct, abduct to control pitch produced);
Rima glottides;
mucous membrane;
micro laryngeal surgery
The intrinsic laryngeal muscles serve to move individual components of the larynx for phonation and breathing:
• Control the rima glottides, length and tension of the vocal folds to change the type of sound produced
• Innervation: __________________ → except cricothyroid (________________________)
recurrent laryngeal nerve (CN X);
external laryngeal branch of superior laryngeal nerve
What is the function of cricothyroid?
Tense → forceful speech
What is the function of Thyroarytenoids (vocalis)?
Relax → softer sounds; adduct (to certain extent)
What is the function of Posterior cricoarytenoids?
Abduct (only muscles able to widen rima glottides)
What is the function of Lateral cricoarytenoids?
Adduct (narrows rima glottides) → modulate tone and volume of speech
