What does the trachea split into?

The trachea splits into two primary bronchi, which is the correct and most relevant answer. This bifurcation occurs at a location known as the carina, typically around the level of the fifth thoracic vertebra. Each bronchus subsequently leads into one of the lungs, further branching into smaller bronchi and ultimately into bronchioles that end in alveoli where gas exchange takes place.

Understanding this anatomical structure is crucial for coders, especially in the context of respiratory disorders, as many medical coding scenarios require a clear understanding of the respiratory system's function and anatomy. The other options provided do not accurately represent the anatomical relationship involving the trachea. The aorta and vena cava are major blood vessels, while the lungs and alveoli are components of the respiratory system but do not represent the direct anatomical structures into which the trachea splits. Nasal cavities pertain to the upper respiratory tract and are not involved in the bifurcation of the trachea.