Answer
Thoracic surgery, a field in which Carrel was a pioneer, involves surgical procedures on the chest cavity and its contents, including the lungs, heart, esophagus, and other thoracic structures. Carrel's contributions to this field included developing innovative techniques for lung transplantation, esophageal reconstruction, and the treatment of thoracic injuries. His work laid the foundation for modern thoracic surgery and advanced the understanding and treatment of chest-related conditions.