A concave abdomen is usually categorized into physiological factors such as thinness and pathological factors such as trauma and scarring. 1. Physiological factors: if there is a thin body type, body fat is relatively low, there will be the phenomenon of the middle of the abdomen concave, more obvious in the supine position, this is generally a normal physiological situation. Usually appropriate to enhance nutrition, balanced diet, appropriate exercise, to ensure physical health. 2. Pathological factors: may be due to trauma and other factors, if the recent local impact, sharp objects stimulation, causing muscle damage, is likely to lead to local muscle depression. If there is scarring from previous surgery, there will also be downward depression. Serious symptoms should be treated promptly.