Posterior cricoarytenoid muscle

The posterior cricoarytenoid muscles are small, paired intrinsic muscles of the larynx that extend between cricoid cartilage to the arytenoid cartilages in the larynx.

Posterior cricoarytenoid
Muscles of larynx. Side view. Right lamina of thyroid cartilage removed.
Details
Origin	posterior part of the cricoid
Insertion	posterior surface of muscular process of the arytenoid cartilage
Nerve	recurrent laryngeal nerve branch of the vagus
Actions	abducts and laterally rotates the cartilage, pulling the vocal ligaments away from the midline and forward and so opening the rima glottidis
Antagonist	Lateral cricoarytenoid muscle
Identifiers
Latin	Musculus cricoarytaenoideus posterior
TA98	A06.2.08.004
TA2	2196
FMA	46576
Anatomical terms of muscle

Structure

Origin and Insertion

The posterior cricoarytenoid originates from the posterior surface of the posterior quadrate lamina of the cricoid cartilage. It inserts onto the posterior surface of the muscular process of the arytenoid cartilage.

Nerve supply

The posterior cricoarytenoid muscles are innervated by the recurrent laryngeal nerve, a branch of the vagus nerve (CN X).

Function

The posterior cricoarytenoid muscles are the only muscles to open the vocal cords. By rotating the arytenoid cartilages laterally, these muscles abduct the vocal cords and thereby open the rima glottidis.[1] ^:9 Their action opposes the lateral cricoarytenoid muscles.

Clinical significance

Paralysis of the posterior cricoarytenoid muscles may lead to asphyxiation as they are the only laryngeal muscles to open the true vocal folds, allowing inspiration and expiration.[2]

Additional images

• 
  The cartilages of the larynx. Posterior view.
• 
  Muscles of larynx. Posterior view.
• 
  Muscles of the larynx, seen from above.
• 
  Dissection of the muscles of the palate from behind.
• 
  Posterior cricoarytenoid muscle
• 
  Posterior cricoarytenoid muscle
• 
  Posterior cricoarytenoid muscle

See also

• Recurrent laryngeal nerve

References

1. Hydman, Jonas (2008). Recurrent laryngeal nerve injury. Stockholm. ISBN 978-91-7409-123-6.
2. The Arytenoid Cartilages - a clinical overview. 2002, Dr. C Kay et al. Thorne Publishing (C)

External links

• Atlas image: rsa4p2 at the University of Michigan Health System
• lesson11 at The Anatomy Lesson by Wesley Norman (Georgetown University) (larynxmuscles)