When there is more fluid in the abdominal cavity (about 1000 ml or more), the gravitational fluid accumulates in the lower part of the abdominal cavity, so there is a turbid sound on percussion. During the examination, the patient is first placed on his back and percussion is performed from the middle to the left side. This phenomenon of movement of the turbid zone due to change of position is called “mobile turbidity” (shifting dullness) and is an important test to confirm the presence of fluid in the abdominal cavity. The mechanism of percussion is that when the patient with fluid in the abdominal cavity is in the supine position, the fluid accumulates in the low part of the abdominal cavity due to gravity, and the intestinal tube containing gas floats on it, so the percussion shows a drum sound in the middle of the abdomen and turbid sounds on both sides of the abdomen. When the patient is in the lateral position, the fluid accumulates in the lower part and the intestinal tube floats upward, so the lower abdomen turns to turbid sounds. Starting from the umbilicus, the patient was asked to percuss to the left until a turbid sound appeared, and the percussion board finger was not moved. The patient was asked to lie on the right side and percuss to the right until a turbid sound appeared again. When there is a large amount of free fluid in the abdominal cavity during the abdominal examination of the physical examination, fluid thrill, or fluctua-tion, can be felt if the abdomen is tapped with the finger. When the patient is lying down, the physician applies the palm of one hand to the abdominal wall on one side of the patient and flexes the four fingers of the other hand together and taps the abdominal wall on the opposite side with the end of the finger (or percussive palpation with the end of the finger). To prevent the transmission of vibrations from the abdominal wall itself to the contralateral side, this can be stopped by having another person press the ulnar edge of the palm against the umbilical mid-abdominal line, as shown. This method of checking ascites requires more than 3000 to 4000 ml of fluid to be detected and is not as sensitive as mobile turbid tones.