0 a Latin word meaning "transverse" (= from side to side), used in medical names and descriptions
Normally, the pleuroperitoneal membranes fuse with the septum transversum, oesophageal mesentery and body wall by seven weeks of gestation.
Though not derived from the septum transversum, development of the liver is highly dependent upon signals originating here.
After migration of hepatoblasts into the septum transversum mesenchyme, the hepatic architecture begins to be established, with liver sinusoids and bile canaliculi appearing.
During subsequent weeks the dorsal end of the embryo grows much faster than its ventral counterpart resulting in an "apparent descent" of the ventrally located septum transversum.
The septum transversum, the primitive central tendon of the diaphragm, originates at the rostral pole of the embryo and is relocated during longitudinal folding to the ventral thoracic region.
The surrounding mesocardium degenerates to leave the primitive heart attached only by its arterial and venous ends, which are anatomically fixed to the pharyngeal arches and the septum transversum, respectively.
Besides of signals from the septum transversum mesenchyme, fibroblast growth factor from the developing heart also contribute to hepatic competence, along with retinoic acid emanating from the lateral plate mesoderm.
