Which structure is the only continuous circular cartilage of the trachea?

Which structure is the only continuous circular cartilage of the trachea?

• A. Thyroid cartilage
• B. Epiglottis
• C. Tracheal rings
• D. Cricoid cartilage

Answer: (D)

The structure that forms a complete circular cartilage around the airway is the cricoid cartilage. It sits just below the thyroid cartilage and forms a full ring, providing rigid support at the upper trachea and larynx junction. In contrast, the thyroid cartilage is a shield-shaped structure on the anterior larynx, not a complete ring; the epiglottis is a single leaf-shaped cartilage that covers the laryngeal inlet during swallowing; and the trachea itself is supported by C-shaped cartilaginous rings that are open posteriorly to allow esophageal expansion, not a continuous circle.

The structure that forms a complete circular cartilage around the airway is the cricoid cartilage. It sits just below the thyroid cartilage and forms a full ring, providing rigid support at the upper trachea and larynx junction. In contrast, the thyroid cartilage is a shield-shaped structure on the anterior larynx, not a complete ring; the epiglottis is a single leaf-shaped cartilage that covers the laryngeal inlet during swallowing; and the trachea itself is supported by C-shaped cartilaginous rings that are open posteriorly to allow esophageal expansion, not a continuous circle.