The earliest division of internal surgery was mainly based on moving knife and not moving knife. All those who need to operate are called surgical diseases, and those who don't need surgery are collectively called internal diseases. Later, with the continuous development of medicine and the continuous application of new technologies, the scope of surgery is also changing, and the branches are getting thinner and thinner, so there are cases of internal and external intersection, such as cholecystitis and appendicitis, which can be cured by conservative treatment. However, it has become a surgical disease. For example, tuberculosis is a medical disease, and later it became a tuberculosis department independently, but when tuberculosis cavity appears, surgery will be performed. For another example, stomatology was originally a surgical category, but stomatology is divided into stomatology and stomatology. For example, heart disease was originally a medical disease, and now the cardiology department still does cardiac catheterization, cardiac stent and other operations.
Therefore, the current division of internal medicine and surgery has a conventional nature, and there is no clear dividing line. Even in the hospital, there will be wrangling with each other because the boundaries of internal and surgical branches are unclear.