Plank abdomen refers to acute diffuse peritonitis due to acute gastrointestinal perforation or organ rupture, where the peritoneum is irritated and causes spasm of the abdominal muscles, and the abdominal wall is often markedly tense and even straight and hard like a plank, hence the name. For example, acute gastrointestinal perforation, acute necrotizing pancreatitis, intestinal perforation, acute appendicitis, or organ rupture, as well as gynecological diseases may occur. In severe cases, it can cause a drop in blood pressure and systemic toxic reaction, and if not treated in time, it can lead to death by toxic shock. Some patients may have pelvic abscess, inter-intestinal abscess, and subphrenic abscess, iliac fossa abscess, and adhesive bowel obstruction. The diagnosis of lamellar abdomen is based on: 1, the peritoneum is stimulated and causes abdominal muscle spasm, the abdominal wall often has a significant sense of tension, and even tense and hard as a plank. 2, plate abdomen is an acute abdomen, the accompanying symptoms of peritonitis, feel the entire abdominal muscle is very hard, is a protective response to the stimulation of the visceral nerves. Plank abdomen need to be distinguished from the following symptoms: 1, frog-like abdomen: appear in a large number of patients with ascites, lying there like a frog’s stomach, water pushed the belly to the sides, mainly in patients with cirrhosis, hypoproteinemia. 2, boat-shaped abdomen: when the patient lies on his back, the anterior abdominal wall is diffusely and obviously concave. In severe cases, the anterior abdominal wall depression almost close to the spine, the rib arch, iliac crest and pubic symphysis are exposed, the whole abdomen is boat-shaped, called boat-shaped abdomen.