The
peritoneum is the
epithelial[?] lining of the
body cavity (
coelom). In higher
vertebrates, the peritoneum is the lining of the
abdominal cavity in particular; the corresponding tissue in the pleural and pericardial cavities of the
thorax[?] is called the
pleura[?] and the
pericardium respectively. The peritoneum is a thin layer of tissue made of flat cells.
A serious medical condition called peritonitis occurs when the peritoneum becomes infected.