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How do the cartilage rings keep the trachea open?

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Illustration showing different animals and their respiratory organs: a spider with book lungs, a chicken with lungs, a sponge with labeled inflow and outflow pores, a fish with gills, and a caterpillar with spiracles. — Respiratory system Different methods of respiration in animals.

The trachea is supported by a series of 16 to 20 horseshoe-shaped cartilage rings that provide structural stability to the windpipe. These rings encircle the front and sides of the trachea, acting as a rigid framework that prevents the airway from collapsing.1

Because these structures are individual rings rather than a single continuous sheath, they allow the trachea to remain flexible, enabling it to stretch and descend during breathing movements. The open ends of these horseshoe-shaped rings face the esophagus and are connected by muscle bands. These muscles can contract to narrow the tracheal lumen, such as during a cough, but the cartilage rings themselves serve as the primary support to keep the airway open under normal conditions.1