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 (3/5th) or glottis vocalis.
It is opened by the posterior cricoarytenoid muscles.
It is limited posteriorly by interarytenoid fold of mucous membrane. The shape of Rima glottidis is changed by movements of vocal cords.
It is the narrowest part of larynx. It is longer (23mm) in males than in females (17mm).
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. Any damage to the rima glottidis may result in a hoarse voice, aphonia or difficulty breathing.