The muscles of the larynx

Larynx

The larynx , commonly called the voice box, is an organ in the neck of amphibians, reptiles and mammals involved in breathing, sound production, and protecting the trachea against food aspiration. It manipulates pitch and volume...

 are extrinsic, passing between the larynx and parts around; and intrinsic, confined entirely to the larynx.

The intrinsic muscles are divided into respiratory and the phonatory muscles (the muscles of phonation

Phonation

Phonation has slightly different meanings depending on the subfield of phonetics. Among some phoneticians, phonation is the process by which the vocal folds produce certain sounds through quasi-periodic vibration. This is the definition used among those who study laryngeal anatomy and physiology...

). The respiratory muscles move the vocal chords 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

Posterior cricoarytenoid muscle

The posterior cricoarytenoid muscles are extremely small, paired muscles that extend from the posterior cricoid cartilage to the arytenoid cartilages in the larynx. By rotating the arytenoid cartilages laterally, these muscles abduct the vocal cords and thereby open the rima glottidis. Their action...

s. The phonatory muscles are divided into adductors (lateral cricoarytenoid muscle

Lateral cricoarytenoid muscle

The lateral cricoarytenoid muscles extend from the lateral cricoid cartilage to the ipsilateral arytenoid cartilage. By rotating the arytenoid cartilages medially, these muscles adduct the vocal cords and thereby close the rima glottidis, protecting the airway...

s, arytenoid muscle

Arytenoid muscle

The arytenoid is a single muscle, filling up the posterior concave surfaces of the arytenoid cartilages.It arises from the posterior surface and lateral border of one arytenoid cartilage, and is inserted into the corresponding parts of the opposite cartilage.It consists of oblique and transverse...

s) and tensors (cricothyroid muscle

Cricothyroid muscle

The cricothyroid muscle is the only tensor muscle of the larynx, aiding with phonation. It attaches to the anterolateral aspect of the cricoid and the inferior cornu and lower lamina of the thyroid cartilage, and its action tilts the thyroid forward to help tense the vocal cords...

s, thyroarytenoid muscle

Thyroarytenoid muscle

The thyroarytenoid is a broad, thin muscle that lies parallel with and lateral to the vocal fold and that supports the wall of the ventricle and its appendix...

s).