In clinical practice, some people have a prominent occipital convexity at the back of the head, so it will appear as a protrusion, which is physiological and does not require special treatment. In some people, the back of the head is not very well developed due to partial thinness and development during childhood. The protruding deformity of the back of the head due to sleeping on the side is also an acquired developmental problem and does not require special treatment. Bleeding in the back of the head area due to trauma, etc., can lead to the formation of a local hematoma over time, which can also bulge a bag, but rather due to soft tissue bleeding, leading to the formation of a hematoma. Localized osteophytes or other occupying lesions can also lead to the formation of a bag. After this occurs, it is best to go to the hospital for a cranial CT examination to see if there is any problem. Generally, after the cranial CT examination, the nature of the bag can be basically clarified and the need for treatment will be clear. There are bags that may be physiological or pathological, but most of them do not require special treatment. If you are really unsure, it is best to go to the hospital for a CT examination, under the diagnosis of the doctor can make a clear treatment.