Trachea.

The trachea, commonly referred to as the windpipe, is the part of the airway that connects the larynx to the two main bronchi. The trachea is made up of sixteen to twenty hyaline cartilage rings that maintain the airway lumen width at about 2.5 centimeters. The cartilage rings are incomplete and flattened posteriorly, where they are completed by fibrous tissue and muscle fibers. The first cartilage ring is thicker than the others and connected by the cricotracheal ligament to the lower edge of the cricoid cartilage of the larynx. At its lower end, the trachea bifurcates into the right bronchus, which is wider, shorter, and more vertical, and the left bronchus which is narrower. This explains why aspirated foreign bodies are more likely to lodge in the right bronchus. The length of the trachea from top to bottom in an adult is 10 to 12 centimeters.