The animation starts with a detailed description of a 19-day-old embryo shown in the mediosagittal plane. The appearance of the septum transversum and the heart tube is then shown for a 22-day-old embryo. The next sequence shows the development of the septum transversum and the beginning of the penetration of the liver bud for a 24-day-old embryo. A transversal segment, cut through the middle part of the embryo and magnified in 3D, presents a slice of the heart, the foregut (esophagus), left and right vitelline veins, dorsal aorta, septum transversum, pericardioperitoneal canals, pericardial cavity, peritoneal cavity, vitelline duct, liver bud and other structures. After the removal of the heart slice, the segment is reoriented towards the spectator and magnified again. The diagram at the end of this sequence shows the septum transversum, which separates the pericardial cavity from the peritoneal cavity and the other mentioned structures, is then viewed under higher magnification. It also indicates the midgut, pleuroperitoneal folds, pancreatic buds, gallbladder outgrowth, amnion, ectoderm and somatopleuric mesoderm.

The next sequence animates the growth of the septum transversum and the pleuroperitoneal folds (i.e. pleuroperitoneal membranes), which narrow the pericardioperitoneal canals, during the 5th week. At the same time, the proximal portion of the right vitelline vein moves to the right, and the corresponding segment of the left vitelline vein is obliterated. The liver bud invades the septum transversum, and the future bile duct forms. In the next sequence, two arrows indicate the extent of the still-open pericarioperitoneal canals.

The animation for the 5- and the 6-week-old embryos shows the fusion of the septum transversum with the pleuroperitoneal membranes, i.e. the closure of the pericardioperitoneal canals with the consecutive separation of the thoracic cavity from the peritoneal cavity. In parallel, the growth of the liver bud, the formation of the lesser omentum and the falciform ligament as well as the obliteration of the left vitelline vein is demonstrated.

The next series shows the completion of the diaphragm in the 7th week. The diagram shows the composition of the diaphragm and the ventral mesentery. The next sequence is dedicated to the growth of the liver and the formation of its bare area.

Several sequences are dedicated to the development of the diaphragm as viewed from above. The first starts with an approximately 24-day-old embryo viewed in the future peritoneal cavity. The vitelline veins, esophagus within the mesoesophagus, aorta, pleuroperitoneal folds and septum transversum are indicated. In the next sequence which ends with the beginning of the 5th week, the pleuroperitoneal folds and the septum transversum grow and approach one another. Meanwhile, the right vitelline vein moves to the right, and the left vitelline vein is obliterated. The growth of the mesoesophagus is also animated. The next sequence, ending with an approximately 8-week-old fetus, shows further development of the diaphragm. The last sequence shows the structure of the diaphragm for an approximately 4-month-old fetus and describes the origin of all components as well as presence of the hepatic portion of the inferior vena cava.

The animation ends with some diaphragmatic malformations, such as congenital diaphragmatic hernia, parasternal hernia and hiatal hernia as viewed from above and from the front.

(This animation is essential for students of medicine as well as departments of anatomy, histology, embryology and cell biology; it is also recommended for departments or clinics for pediatrics and pediatric surgery as well as students of biology, veterinary medicine and stomatology.)