The cricothyroid is the only intrinsic laryngeal muscle innervated by the external branch of the superior laryngeal nerve rather than the recurrent laryngeal nerve. By tilting the thyroid cartilage forward relative to the cricoid it stretches and tenses the vocal cords, raising vocal pitch. Cricothyroid dysfunction from superior laryngeal nerve injury produces inability to produce high-pitched notes, a subtle but diagnostically important voice change distinct from the hoarseness of RLN palsy.
| Origin | Anterolateral surface of the cricoid arch |
|---|---|
| Insertion | Two parts: the straight part (pars recta) to the inferior border of the thyroid lamina and the oblique part (pars obliqua) to the inferior horn of the thyroid cartilage |
| Nerve Supply | External branch of the superior laryngeal nerve (CN X) |
| Blood Supply | Superior laryngeal artery |
| Actions |
|
|---|
Without cricothyroid action the voice is limited to its lower frequency range, as the muscle is essential for producing the head voice and falsetto registers that require maximum cord elongation.
The external branch of the superior laryngeal nerve runs on the inferior pharyngeal constrictor close to the superior thyroid artery before reaching the cricothyroid, so it is at risk when the superior thyroid pole vessels are tied during thyroidectomy, especially when it crosses below the upper border of the pole (Cernea type 2b). Injury causes loss of high notes, a reduced vocal range and voice fatigue rather than the obvious hoarseness of recurrent laryngeal nerve damage, and may go unrecognised unless the patient is asked to sing their highest notes. Ligating the vessels individually close to the thyroid capsule, and identifying the nerve, protects it.
The cricothyroid muscle is palpable in the midline neck between the thyroid and cricoid cartilages, becoming firm during high-pitched vocalisation.
Cricothyroid denervation from thyroid surgery producing inability to produce high vocal pitches without hoarseness, a subtle complication that may be missed without specific voice testing.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
