The structure within the mediastinum, anterior to the vertebrae and posterior to the trachea is the .

The structure you are referring to within the mediastinum, which is located anterior to the vertebrae and posterior to the trachea, is the esophagus. The esophagus serves as the conduit for food and liquids that have been swallowed into the pharynx to reach the stomach. It runs through the mediastinum and is distinguished by its muscular wall, which aids in the movement of food through peristalsis. The mediastinum itself is the central compartment of the thoracic cavity and contains various critical structures including the heart, large vessels, trachea, esophagus, and lymph nodes.