Final answer:
The layer that surrounds the esophagus in the thorax is called the adventitia.
Step-by-step explanation:
The layer that surrounds the esophagus in the thorax is called the adventitia. The adventitia is the most superficial layer of the esophagus and it is composed of loose connective tissue.
Unlike the serosa that covers the stomach and intestines, the adventitia is not covered by a fold of visceral peritoneum.