Rima glottidis

The rima glottidis is the opening between the true vocal cords and the arytenoid cartilages of the larynx.

It is normally subdivided into two parts: that between the arytenoid cartilages is called the intercartilaginous part (or the intercartilaginous glottis, respiratory glottis, or interarytenoid space), and that between the vocal folds the intermembranous part or glottis vocalis.

It is closed by the lateral cricoarytenoid muscles and the arytenoid muscle.

It is opened by the posterior cricoarytenoid muscles.

All of these muscles receive their innervation from the recurrent laryngeal nerve which is a branch of the vagus nerve (CN X). This nerve can be vulnerable in thyroid surgery, if damaged control to the rima glottidis may be affected resulting in a hoarse voice, aphonia or difficulty breathing.