The lateral cricoarytenoid (also anterior cricoarytenoid) is an intrinsic muscle of the

larynx The larynx (), commonly called the voice box, is an organ (anatomy), organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal ...

. It attaches at the cricoid cartilage anteriorly, and at the

arytenoid cartilage The arytenoid cartilages () are a pair of small three-sided pyramids which form part of the larynx. They are the site of attachment of the vocal cords. Each is pyramidal or ladle-shaped and has three surfaces, a base, and an apex. The arytenoid ...

of the same side posteriorly. It is innervated by the

recurrent laryngeal nerve The recurrent laryngeal nerve (RLN), also known as nervus recurrens, is a branch of the vagus nerve ( cranial nerve X) that supplies all the intrinsic muscles of the larynx, with the exception of the cricothyroid muscles. There are two recur ...

. It acts to close the

rima glottidis The rima glottidis is the opening between the two true vocal cords anteriorly, and the two arytenoid cartilages posteriorly. It is part of the larynx. Anatomy The rima glottidis is the narrowest part of larynx. It is longer (~23 mm) in ...

, thus closing the

airway The respiratory tract is the subdivision of the respiratory system involved with the process of conducting air to the alveoli for the purposes of gas exchange in mammals. The respiratory tract is lined with respiratory epithelium as respiratory ...

Anatomy

The muscle is directed obliquely superoposteriorly from its anterior attachment to its posterior attachment.

Attachments

The muscle's anterior attachment is onto the superior border of the arch of the cricoid cartilage. Its posterior attachment is onto the anterior aspect of the muscular process of the ipsilateral

Innervation

The muscle receives motor innervation from (branches of the anterior terminal division of) the

(which is in turn a branch of a vagus nerve (CN X)).

Actions/movements

The muscle rotates the arytenoid cartilage medially (it thus acts as antagonist to the posterior cricoarytenoid muscle which rotates the cartilage laterally).

Function

The muscle closes the

, adducting (approximating) the apices of the vocal process to close the ligamentous part of rima glottidis (in which it is synergystic with the oblique arytenoid muscles and transverse arytenoid muscle). It thus functions to close the

. It also shortens and slackens the vocal cords.

Additional images

File:Gray960.png, Muscles of the larynx, seen from above.

References

External links

* * () Muscles of the head and neck {{muscle-stub