Major Thoracic refers to a significant area of the human body, specifically the thorax, which houses vital organs such as the heart and lungs. This region is protected by the rib cage and plays a crucial role in respiration and circulation. The thoracic cavity is divided into three parts: the left pleural cavity, the right pleural cavity, and the mediastinum, which contains the heart, trachea, and esophagus. In medical contexts, the term "Major Thoracic" may also relate to surgical procedures or conditions affecting the thoracic region. For instance, thoracic surgery involves operations on organs within the thorax, while thoracic outlet syndrome refers to a group of disorders that occur when blood vessels or nerves in the thoracic outlet are compressed.