The glottis is the cartilage surrounding the hole otherwise known as the windpipe. It is the opening into the larynx and then the trachea to get to the lungs. At its entrance is the epiglottis and the arytenoid cartilages. Behind the arytenoid cartilages are the vocal chords of the larynx, the thyroid cartilages, and the cricoid cartilages.

In this picture the glottis is labeled to the left. The big black space in the center of the picture is the formation of the glottis.