From the Research
The subglottis is the portion of the larynx that extends from the lower border of the vocal folds (true vocal cords) down to the inferior border of the cricoid cartilage, where it transitions into the trachea. This definition is based on the most recent and highest quality study available, which provides a detailed analysis of the subglottic region 1. The subglottis forms the lowest segment of the laryngeal cavity, measuring approximately 1-2 cm in height in adults. Anatomically, the subglottis is completely encircled by the cricoid cartilage, which is the only complete cartilaginous ring in the laryngeal framework. This complete ring provides structural support and maintains airway patency. The subglottic region is lined with respiratory epithelium (pseudostratified ciliated columnar epithelium) and contains numerous submucosal glands. Some of the key features of the subglottis include:
- The inferior arcuate line of the vocal cord as the cranial border
- The lower margin of the cricoid as the caudal border
- The elastic cone and cricoid forming the craniolateral border
- The median part of the cricothyroid ligament and the cricoid cartilage forming the ventral and dorsal boundaries, respectively 1. This area is clinically significant as it represents the narrowest portion of the airway in children, making it particularly vulnerable to obstruction from conditions like subglottic stenosis, croup, or foreign body aspiration. The subglottis also serves as an important landmark for procedures such as cricothyroidotomy and certain types of intubation. While other studies provide additional information on the subglottis, such as its microvasculature 2 and treatment options for subglottic stenosis 3, 4, 5, the definition and anatomical description provided by 1 remain the most accurate and relevant.