lateral plate

The lateral plate mesoderm is a layer of embryonic tissue that splits into two layers: the somatic and splanchnic layers. The space between them is called the coelom. As the embryo folds, this coelom becomes a single cavity that develops into the pericardial cavity (for the heart), pleural canals (for the lungs), and peritoneal cavity (for abdominal organs).1

The mesoderm is one of the three primary germ layers that form during embryonic development. It gives rise to muscles, the circulatory and excretory systems, gonads, and the internal skeleton. Specifically, the mesoderm contributes to the development of bones, including the vertebral column, ribs, and parts of the skull. It also forms the body muscles.234