The cricothyroid muscle is the only tensor muscle of the
larynx aiding with
phonation. It is innervated by the superior laryngeal nerve. Its action tilts the
thyroid forward to help tense the
vocal cords
In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speec ...
.
Structure
The cricothyroid muscle originates from the anterolateral aspect of the
cricoid cartilage, and inserts to the inferior
cornu and lower
lamina
Lamina may refer to:
Science and technology
* Planar lamina, a two-dimensional planar closed surface with mass and density, in mathematics
* Laminar flow, (or streamline flow) occurs when a fluid flows in parallel layers, with no disruption betwee ...
of the
thyroid cartilage.
Innervation
This muscle is the only laryngeal muscle innervated by the superior laryngeal branch of the
vagus nerve known as the
superior laryngeal nerve
The superior laryngeal nerve is a branch of the vagus nerve. It arises from the middle of the inferior ganglion of vagus nerve and in its course receives a branch from the superior cervical ganglion of the sympathetic nervous system.
The superi ...
.
Function
The cricothyroid muscle produces tension and elongation of the
vocal cords
In humans, vocal cords, also known as vocal folds or voice reeds, are folds of throat tissues that are key in creating sounds through vocalization. The size of vocal cords affects the pitch of voice. Open when breathing and vibrating for speec ...
.
They draw up the arch of the
cricoid cartilage and tilt back the upper border of the cricoid cartilage lamina.
The distance between the vocal processes and the angle of the thyroid is increased, and the folds are consequently elongated, resulting in higher pitch
phonation.
They work as antagonists to the
posterior cricoarytenoid muscles.
Clinical significance
The cricothyroid muscles may be injected with
botulinum toxin whilst treating
spasmodic dysphonia.
This is usually performed under guidance from
electromyography.
Additional images
File:Gray560.png, The veins of the thyroid gland.
File:Gray562.png, The fascia and middle thyroid veins.
File:Gray957.png, Side view of the larynx, showing muscular attachments.
See also
*
Cricothyroid ligament
*
Larynx
*
vocal fold
*
Thyroid cartilage
*
Vocology - science and practice of voice habilitation
*
Adam's apple
*
Phonation
*
National Center for Voice and Speech
*
Cricothyroid approximation
References
{{DEFAULTSORT:Cricothyroid Muscle
Muscles of the head and neck