In modern society, the gradual strengthening of national health care awareness and the improvement of social and work welfare have led many people to give more attention to their health. Compared with the simple examinations such as chest X-ray and chest X-ray, the medical examination methods nowadays are on a higher level with the progress of science and technology. But after the checkup, people are often full of doubts and confusion when they are faced with a lot of numbers and terminology of the checkup. Some people even make up for their lack of medical expertise by using a doula or their own brains, causing them to fall into anxiety. How to objectively and scientifically evaluate your own medical report? It is recommended that people listen to professional doctors to get advice that is beneficial to their health. I am a thoracic surgeon, and I often meet people who have nothing to do after medical checkups during my outpatient visits. Here, I would like to combine what I have seen and heard to popularize some knowledge about the results of thoracic medical examinations, which I hope will be helpful to you. As mentioned before, the current medical examination technology has improved, and the chest examination is often performed by CT scan, so that some small lesions in the chest can be detected early, such as: small nodules in the lungs, small tumors in the mediastinum, etc.. We hope to talk about the small nodules in the lung in detail later, so we will not expand on them here, but let’s talk about the small mediastinal tumors first. Mediastinal tumors have their unique characteristics: first of all, the mediastinum is a structure rather than an organ, and it contains many tissues and organs. Where is the mediastinum? The mediastinum is located in the middle of the thoracic cavity, on the central axis of the body, looking down, directly behind the sternum. The mediastinum is the general term for the organs and tissues between the left and right mediastinal pleura and the organs and tissues trapped between them, including the heart and the large blood vessels entering and leaving the heart, the esophagus, the trachea, the thymus, the nerves and the lymphatic tissue. Because of the large number of organs in the mediastinum and the complex origin of the tissues, the predecessors in the medical field have artificially defined the mediastinum into upper and lower mediastinum in order to facilitate its classification and description: the mediastinum is usually divided into upper and lower mediastinum by the imaginary plane of the sternal angle and the lower edge of the 4th thoracic vertebra. The inferior mediastinum is further divided into 3 parts: the anterior mediastinum, the middle mediastinum, and the posterior mediastinum, with the pericardium as the boundary. The anterior mediastinum is the narrow area between the sternum and the pericardium; the posterior mediastinum is located between the pericardium and the spine; and the middle mediastinum is where the pericardium is located. If you feel a little dizzy, try to imagine the mediastinum as a villa, divided into two floors, the upper floor has only one room, while the lower floor has three rooms, arranged longitudinally from front to back, let’s call it the anterior, middle and posterior halls, the middle hall is where our heart and its protective layer, the pericardium, live. Why is the mediastinum divided into so many chambers? This is the second characteristic of mediastinal tumors: there are more tissues and organs in the mediastinum, and the tumors are more complicated in origin, so our villa is like a group house, different rooms are divided into different people. Now let’s get to know what are the frequent residents: thymoma, retrosternal thyroid mass, blastocytoma, parathyroid mass, lipoma, fibroma, hemangioma, cystic hydatid tumor, prominent cerebrospinal membrane, enlarged lymph nodes, lymphoma, neurogenic tumor, etc. It seems that there are quite a lot of tumors that frequent our mediastinum, so don’t worry, we will introduce their past lives and preferences later. Of course, no one wants their mediastinum to become a group house and a place for these tumors to live, so once the existence of these tumors is detected during a medical checkup, I still recommend you to see a thoracic surgeon, who will give you some pertinent advice based on your condition. Since most mediastinal tumors can only be removed surgically, the timing and pros and cons of the surgery need to be discussed between you and your doctor.