Cricothyroid muscle

Not to be confused with Posterior cricoarytenoid muscle.
Cricothyroid muscle
Muscles of larynx. Side view. Right lamina of thyroid cartilage removed.
The ligaments of the larynx. Antero-lateral view.
Details
OriginAnterior and lateral cricoid cartilage
InsertionInferior cornu and lamina of the thyroid cartilage
NerveExternal branch of superior laryngeal nerve (branch of the vagus nerve)
ActionsTension and elongation of the vocal folds
Identifiers
Latinmusculus cricothyroideus
TA98A06.2.08.001
TA22193
FMA46417
Anatomical terms of muscle

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, thus increasing the pitch of the voice.

Structure

The cricothyroid muscle is a fan-shaped muscle situated at the outer surface of the larynx.[1]

Origin

The cricothyroid muscle originates from the anterolateral aspect of the cricoid cartilage.[2]

Insertion

The cricothyroid muscle splits into two groups or parts. The oblique part travels posterolaterally and inserts onto the inferior cornu of the thyroid cartilage. The straight part travels posterosuperiorly and inserts onto the inferior margin of the lamina of the thyroid cartilage.[1]

Innervation

The cricothyroid muscle is innervated by the external branch of the superior laryngeal nerve (a branch of the vagus nerve). It is the only muscle innervated by this nerve.[3][4]

Function

The cricothyroid muscle produces tension and elongation of the vocal cords.[3][5] They draw up the arch of the cricoid cartilage and tilt back the upper border of the cricoid cartilage lamina.[3][5] The distance between the vocal processes and the angle of the thyroid is increased, elongating[3] and thus tensing the vocal folds,[1] thereby resulting in higher pitch phonation.[3] They work as antagonists to the posterior cricoarytenoid muscles.[6]

Clinical significance

The cricothyroid muscles may be injected with botulinum toxin whilst treating spasmodic dysphonia.[6] This is usually performed under guidance from electromyography.[6]

Additional images

  • The veins of the thyroid gland.
    The veins of the thyroid gland.
  • The fascia and middle thyroid veins.
    The fascia and middle thyroid veins.
  • Side view of the larynx, showing muscular attachments.
    Side view of the larynx, showing muscular attachments.

See also

References

  1. ^ a b c Sinnatamby, Chummy (2011). Last's Anatomy (12th ed.). Elsevier Australia. p. 395. ISBN 978-0-7295-3752-0.
  2. ^ "Cricothyroid". www.meddean.luc.edu. Retrieved 2022-06-06.
  3. ^ a b c d e Duarte, Robert A.; Argoff, Charles E. (2009-01-01), Argoff, Charles E.; McCleane, Gary (eds.), "Chapter 19 - Glossopharyngeal and other Facial Neuralgias", Pain Management Secrets (Third Edition), Philadelphia: Mosby, pp. 116–118, ISBN 978-0-323-04019-8, retrieved 2021-01-12
  4. ^ Kaplan, Edwin L.; Angelos, Peter; James, Benjamin C.; Nagar, Sapna; Grogan, Raymon H. (2016-01-01), Jameson, J. Larry; De Groot, Leslie J; de Kretser, David M.; Giudice, Linda C. (eds.), "Chapter 96 - Surgery of the Thyroid", Endocrinology: Adult and Pediatric (Seventh Edition), Philadelphia: W.B. Saunders, pp. 1666–1692.e4, doi:10.1016/b978-0-323-18907-1.00096-2, ISBN 978-0-323-18907-1, retrieved 2021-01-12
  5. ^ a b Berke, Gerald S.; Long, Jennifer L. (2010-01-01), Brudzynski, Stefan M. (ed.), "Chapter 10.1 - Functions of the larynx and production of sounds", Handbook of Behavioral Neuroscience, Handbook of Mammalian Vocalization, vol. 19, Elsevier, pp. 419–426, doi:10.1016/B978-0-12-374593-4.00038-3, retrieved 2021-01-12
  6. ^ a b c Bentivoglio, Anna Rita; Fasano, Alfonso; Albanese, Alberto (2009-01-01), Jankovic, Joseph; Albanese, Alberto; Atassi, M. Zouhair; Dolly, J. Oliver (eds.), "10 - Botulinum Neurotoxin in Tremors, Tics, Hemifacial Spasm, Spasmodic Dysphonia, and Stuttering", Botulinum Toxin, Philadelphia: W.B. Saunders, pp. 112–130, doi:10.1016/b978-1-4160-4928-9.00010-x, ISBN 978-1-4160-4928-9, retrieved 2021-01-12