The transverse arytenoid muscle is a single muscle within the larynx which arises from the posterior surface and lateral border of one arytenoid cartilage and is inserted into the corresponding parts of the opposite arytenoid cartilage. It pulls the arytenoids toward each other when they contract, which results in the vocal folds being brought together or adducted (see abduction and adduction of vocal folds). This action closes the rima glottides (the opening of the glottis), especially at its back part.