Lateral Crico-Arytenoid (Left) (Musculus cricoarytenoideus lateralis)

Anatomy

The lateral crico-arytenoid is a triangular intrinsic laryngeal muscle situated on the lateral slope of the cricoid arch. Arising from the upper border of the cricoid cartilage arch, it passes posterosuperiorly to insert onto the muscular process of the arytenoid cartilage. It acts as the primary adductor of the vocal folds for phonation, antagonist to the posterior crico-arytenoid.

Origin & insertion

From the superior margin and lateral surface of the arch of the cricoid cartilage to the muscular process of the arytenoid cartilage.

Action

Adducts the vocal folds by rotating the arytenoid cartilages medially, closing the intermembranous part of the rima glottidis for phonation.

Innervation

Recurrent laryngeal nerve (branch of vagus nerve, cranial nerve X).

Clinical notes

Unilateral recurrent laryngeal nerve palsy paralyzes the lateral crico-arytenoid along with other adductors, leaving the vocal cord immobilized in a paramedian position, causing hoarseness and air leak on phonation.

Related structures

• Cricoid Cartilage
• Left Arytenoid Cartilage

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