Editing Larynx (section)

===Muscles===
The muscles of the larynx are divided into ''intrinsic'' and ''extrinsic'' muscles. The extrinsic muscles act on the region and pass between the larynx and parts around it but have their origin elsewhere; the intrinsic muscles are confined entirely within the larynx and have their origin and insertion there.<ref name="Saladin">{{cite book | vauthors = Saladin KS |title=Human anatomy |date=2011 |publisher=McGraw-Hill |location=New York |isbn=9780071222075 |page=241 |edition=3rd}}</ref>

The intrinsic muscles are divided into respiratory and the phonatory muscles (the muscles of [[phonation]]). The respiratory muscles move the [[vocal cord]]s apart and serve breathing. The phonatory muscles move the vocal cords together and serve the production of voice. The main respiratory muscles are the [[posterior cricoarytenoid muscle]]s. The phonatory muscles are divided into adductors ([[lateral cricoarytenoid muscle]]s, [[arytenoid muscle]]s) and tensors ([[cricothyroid muscle]]s, [[thyroarytenoid muscle]]s).

====Intrinsic====
The intrinsic laryngeal muscles are responsible for controlling sound production.
* [[Cricothyroid muscle]] lengthen and tense the vocal cords.
* [[Posterior cricoarytenoid muscle]]s abduct and externally rotate the arytenoid cartilages, resulting in abducted vocal cords.
* [[Lateral cricoarytenoid muscle]]s adduct and internally rotate the arytenoid cartilages, increase medial compression.
* [[Transverse arytenoid muscle]] adduct the arytenoid cartilages, resulting in adducted vocal cords.<ref>Collectively, the transverse and oblique arytenoids are known as the interarytenoids.</ref>
* [[Oblique arytenoid muscle]]s narrow the [[laryngeal inlet]] by constricting the distance between the arytenoid cartilages.
* [[Thyroarytenoid muscle]]s narrow the laryngeal inlet, shortening the vocal cords, and lowering voice pitch. The internal thyroarytenoid is the portion of the thyroarytenoid that vibrates to produce sound.

Notably the only muscle capable of separating the vocal cords for normal breathing is the posterior cricoarytenoid.  If this muscle is incapacitated on both sides, the inability to pull the vocal cords apart (abduct) will cause difficulty breathing. Bilateral injury to the recurrent laryngeal nerve would cause this condition.  It is also worth noting that all muscles are innervated by the recurrent laryngeal branch of the vagus except the cricothyroid muscle, which is innervated by the external laryngeal branch of the superior laryngeal nerve (a branch of the vagus).

Additionally, intrinsic laryngeal muscles present a constitutive [[Calcium buffering|Ca<sup>2+</sup>-buffering]] profile that predicts their better ability to handle calcium changes in comparison to other muscles.<ref name="Expression of calcium-buffering pro">{{cite journal | vauthors = Ferretti R, Marques MJ, Khurana TS, Santo Neto H | title = Expression of calcium-buffering proteins in rat intrinsic laryngeal muscles | journal = Physiological Reports | volume = 3 | issue = 6 | page = e12409 | date = June 2015 | pmid = 26109185 | pmc = 4510619 | doi = 10.14814/phy2.12409 }}</ref> This profile is in agreement with their function as very fast muscles with a well-developed capacity for prolonged work. Studies suggests that mechanisms involved in the prompt sequestering of Ca<sup>2+</sup> (sarcoplasmic reticulum Ca<sup>2+</sup>-reuptake proteins, plasma membrane pumps, and cytosolic Ca<sup>2+</sup>-buffering proteins) are particularly elevated in laryngeal muscles, indicating their importance for the myofiber function and protection against disease, such as [[Duchenne muscular dystrophy]].<ref name="onlinelibrary.wiley.com">{{cite journal | vauthors = Marques MJ, Ferretti R, Vomero VU, Minatel E, Neto HS | title = Intrinsic laryngeal muscles are spared from myonecrosis in the mdx mouse model of Duchenne muscular dystrophy | journal = Muscle & Nerve | volume = 35 | issue = 3 | pages = 349–353 | date = March 2007 | pmid = 17143878 | doi = 10.1002/mus.20697 | s2cid = 41968787 }}</ref> Furthermore, different levels of Orai1 in rat intrinsic laryngeal muscles and [[extraocular muscle]]s over the limb muscle suggests a role for store operated [[Calcium channel|calcium entry channels]] in those muscles' functional properties and signaling mechanisms.

====Extrinsic====
The extrinsic laryngeal muscles support and position the larynx within the mid-cervical cereal region. 
[[File:Gray386.png|thumb|Extrinsic laryngeal muscles]]
* [[Sternothyroid muscle]]s depress the larynx. (Innervated by ansa cervicalis)
* [[Omohyoid muscle]]s depress the larynx. (Ansa cervicalis)
* [[Sternohyoid muscle]]s depress the larynx. (Ansa cervicalis)
* [[Inferior constrictor muscle]]s. (CN X)
* [[Thyrohyoid muscle]]s elevates the larynx. (C1)
* [[Digastric]] elevates the larynx. (CN V<sub>3</sub>, CN VII)
* [[Stylohyoid]] elevates the larynx. (CN VII)
* [[Mylohyoid muscle|Mylohyoid]] elevates the larynx. (CN V<sub>3</sub>)
* [[Geniohyoid]] elevates the larynx. (C1)
* [[Hyoglossus]] elevates the larynx. (CN XII)
* [[Genioglossus]] elevates the larynx. (CN XII)