In anatomy, the peritoneum is the serous membrane of the abdominal cavity, lining the inside of the abdominal wall, the diaphragm, the pelvic area and covering the parietal peritoneum of the chest and back. It performs several important functions: it promotes shock absorption of organs, prevents injury to blood vessels and nerves during contraction of the abdominal muscles, serves as an additional barrier to the penetration of infections into the body, produces fluid (peritoneal), through which nutrients, gases, alcohol and drugs are absorbed.