Lateral crico-arytenoid muscle
Musculus cricoarytendoideus lateralis
The lateral crico-arytenoid is a small laryngeal muscle that runs from the side of the cricoid to the arytenoid and closes the glottis.
At a glance
- English
- Lateral crico-arytenoid muscle
- Latin (TA2)
- Musculus cricoarytendoideus lateralis
- System
- Muscle
- Region
- Neck
- Side
- Paired, left and right
About the lateral crico-arytenoid muscle
The lateral crico-arytenoid is one of the intrinsic muscles of the larynx, the small muscles that move the cartilages of the voice box against each other. It lies on the side of the larynx, deep to the lamina of the thyroid cartilage and below thyro-arytenoid, with which its upper border often blends. It is a short, oblong muscle running backwards and upwards along the arch of the cricoid.
It arises from the upper edge and outer surface of the arch of the cricoid cartilage, on the side of the larynx. Its fibres pass backwards and upwards to the front and side of the muscular process of the arytenoid cartilage, the knob that projects outwards and backwards from the base of each arytenoid, and to the area around it.
By pulling the muscular process forwards, the muscle spins the arytenoid on its vertical axis so that its vocal process swings inwards. This brings the vocal folds together and narrows the rima glottidis, the gap between them. It is therefore the main antagonist of the posterior crico-arytenoid, which turns the cartilage the other way to open the glottis. Working with the arytenoid muscles and thyro-arytenoid, it closes the glottis for speech, coughing and protection of the airway during swallowing.
It is supplied by the recurrent laryngeal nerve, a branch of the vagus, and receives blood from the laryngeal branches of the superior and inferior thyroid arteries. Damage to the recurrent laryngeal nerve, for example in thyroid or chest surgery or from a tumour in the neck or chest, stops the vocal fold on that side from closing fully, leading to a hoarse, breathy voice and a weak cough.
Attachments, action and supply
- Origin
- Upper border and outer surface of the arch of the cricoid cartilage.
- Insertion
- Front of the muscular process of the arytenoid cartilage and the area around it.
- Action
- Rotates the arytenoid so the vocal processes swing inwards, bringing the vocal folds together and closing the glottis.
- Nerve supply
- Recurrent laryngeal nerve (from the vagus, CN X).
- Blood supply
- Laryngeal branches of the superior and inferior thyroid arteries.
Anthromica
See the lateral crico-arytenoid muscle where it really sits, with every layer of the body around it.
- Every layer, one body. Peel from muscle to bone, nerve, vessel and organ, and turn it any way.
- English and Latin. Every structure named the way your exam names it.
- Quiz until it sticks. Short drills on the structures you keep missing.
Free to start. No card.
