AP02 - Larynx Flashcards
What forms the skeleton of the larynx? What muscles move them?
Hyaline and elastic cartilages, they form articulations with each other.
Moved by intrinsic and extrinsic laryngeal muscles
Action of the cricothyroid muscle?
- Rotates thyroid cartilage anteriorly and inferiorly at cricothyroid joint to draw it closer to the cricoid cartilage
- Tense the vocal ligaments by elongating them, increasing vocal pitch
Innervation of cricothyroid muscle?
Vagus nerve (CNX) - external branch of superior laryngeal nerve
Action of posterior cricoarytenoid muscle?
- ABducts the arytenoid cartilage and vocal folds to open rima glottidis
- Laterally/ externally rotates the arytenoid catilage
Which muscle is the only muscle that can open the rima glottidis?
Posterior cricoarytenoid muscle
Innervation of posterior cricoarytenoid muscle?
Vagus nerve - recurrent laryngeal branch
Action of lateral cricoarytenoid muscle?
- ADducts the vocal folds to close the rima glottidis
2. Medially/ internally rotates the arytenoid cartilage
Innervation of lateral cricoarytenoid muscle?
Vagus nerve - recurrent laryngeal branch
Action of transverse arytenoid?
ADducts the arytenoid cartilages
Innervation of transverse arytenoid muscle?
Vagus nerve - recurrent laryngeal branch
Action of oblique arytenoid muscle?
Narrows the laryngeal inlet- acts as weak sphincter
Innervation of oblique arytenoid muscle?
Vagus nerve - recurrent laryngeal branch
Action of thyroarytenoid muscle?
- Narrows laryngeal inlet and vestibule
- Pulls the arytenoid cartilages anteriorly to relax the vocal ligament
- Medically rotates the arytenoid artilages to help close the rima glottidis
Innervation of thyroarytenoid muscle?
Vagus nerve - recurrent laryngeal branch
Action of vocalis?
- Alter the tension of the vocal ligament - relaxes posterior part of vocal ligament while maintaining tension on anterior part
[Sometimes classed as part of the thyroarytenoid muscle]
Innervation of vocalis?
Vagus nerve - recurrent laryngeal branch
What are the muscles of the larynx?
- Cricothyroid
- Posterior cricoarytenoid
- Lateral cricoarytenoid
- Transverse arytenoid
- Oblique arytenoid
- Vocalis
- Thyroarytenoid
What happens to the rima glottidis, rima vestibuli, vestibule and laryngeal inlet during swallowing?
Rima glottidis, rima vestibuli and vestibule are closed.
Laryngeal inlet is narrowed
What happens to the epiglottis during swallowing?
Epiglottis swings downwards towards the arytenoid cartilages (narrows laryngeal inlet)
What is the rima glottidis?
The opening between the true vocal cords and the arytenoid cartilages of the larynx
What are the 3 paired cartilages that make up the larynx walls?
- Arytenoid
- Corniculate
- Cuneiform
What are the 3 unpaired cartilages that make up the larynx walls?
- Cricoid
- Thyroid
- Epiglottis
Where is the larynx located? (which vertebral level)
Anterior neck at C3-C6
