The peritoneum is a thin, two-layered membrane that lines the walls of the abdominal and pelvic cavities (parietal peritoneum) and covers most of the abdominal organs (visceral peritoneum). The space between these layers, the peritoneal cavity, normally contains only a small amount of lubricating fluid. On ultrasound, the peritoneum is not typically visible when normal, but it becomes clinically important when disease is present. Ascites (excess fluid in the peritoneal cavity), peritoneal carcinomatosis (cancer spread to the peritoneum), and peritonitis (infection/inflammation) can all be detected or suggested by sonographic findings. Ultrasound is highly sensitive for detecting even small amounts of free peritoneal fluid, making it invaluable in trauma and acute care settings.
Sonography Term