The endothoracic fascia is a layer of connective tissue that lines the inside of the chest wall and covers the lungs. It is an integral part of the thorax and provides support and protection to the organs in the chest. Some synonyms for the endothoracic fascia include mediastinal fascia, thoracic fascia, and pleural fascia. The mediastinal fascia refers to the connective tissue that separates the two pleural cavities in the chest, while the thoracic fascia is a general term for the layers of tissue that cover the thorax. The pleural fascia specifically refers to the connective tissue that covers the lungs and lines the chest wall.