Boundaries and relations
- superiorly: 1 cm below the lateral margin of the ventricle where the superior surface of the true vocal cord ends , although other definitions exist, such as 5 mm below the free margin of the vocal cord
- inferiorly: inferior margin of the cricoid cartilage
- laterally: conus elasticus/cricovocal membrane and paraglottic space; cricoid cartilage at the most inferior extent
In general, the subglottis is cylindrical but enlarges in diameter as it progresses caudally following the conus elasticus.
The inferior arcuate line of the vocal cord marks the cranial border, defined histologically as the transition point between the squamous epithelium of the true vocal cord and the respiratory epithelium of the subglottis .