Septum Transversum

**Semantic type:** Embryonic Structure

**Definition:** A ventro-dorsal plate of mesoderm, which arises from the coelomic wall of the caudal portion of the pericardial cavity, and which is located caudal to the pericardial cavity, extending from the ventral and lateral regions of the body wall to the foregut in the early embryo; it contributes to the formation of the liver, and it is the primordium of the central tendon of the diaphragm.