Trachea

Description

Prominent laryngeal cartilages sit superior to the proximal trachea, with the thyroid cartilage forming the anterior and lateral walls and the cricoid cartilage encircling the airway inferior to it. Posterior to the cricoid, the paired arytenoid cartilages anchor the vocal folds, while intrinsic laryngeal muscles (including the cricothyroid and posterior cricoarytenoid regions) span between cartilaginous landmarks to control glottic aperture. Inferiorly, the trachea descends in the midline, its anterior and lateral C shaped hyaline cartilage rings contrasted against the more flexible posterior membranous wall. Fine membranes and ligaments bridge the cartilages at the laryngeal inlet and across the cricothyroid interval. Orientation at the cricoid level matters clinically because it marks the transition from larynx to trachea and the narrowest fixed portion of the adult airway. Emergency airway access targets this anatomy: cricothyrotomy passes through the cricothyroid membrane between thyroid and cricoid cartilages, while tracheostomy is placed inferiorly through tracheal rings, commonly between the second and fourth rings to avoid the cricoid and reduce subglottic stenosis risk. The posterior cricoarytenoid region is also a key teaching point, it is the only muscle that abducts the vocal folds, so bilateral recurrent laryngeal nerve injury can leave the cords near midline with airway compromise. Use this illustration in head and neck anatomy courses, otolaryngology teaching files, anesthesia and critical care airway manuals, and surgical atlases discussing tracheostomy, cricothyrotomy, and laryngeal nerve injury patterns. Anatomical accuracy verified by SciePro's Medical Advisory Board.