早期人胎児肝臓の局所解剖学的研究

Abstract

1. The material consists of 5 early human embryos ranging from 4.5 to 10mm in length. Three specimens (4.5, 5 and 7mm) among them are in the developmental stage of Streeter's horizon XIV, the other two (7 [F] and 10mm (F.)) are in that of horizon XV.2. In all these embryos the pleuropericardial canals are yet open.3. The cranial surface of the liver is covered with the mesenchymal tissue of septum transversum and pleuroperitoneale of both sides, only a small lateral area is of peritoneal covering.4. Dorsal to the septum transversum and between both sides septum pleuroperitonealis of the liver, there is mesocardium a little rightward, to the left of it mesogastrium ventrale. In the mesocardium the sinus venosus of the heart goes on to the ductus venosus of the liver, the mesogastrium ventrale adheres to the dorsal and caudal surfacc of the liver.5. In the younger 4 specimens among them the right and left side peritoneal surface are separated completely by the adhesion of the mesogastrium ventrale on the liver, while they are continuous dorsal to the V. umbilicalis in the eldest 10mm long embryo.6. This continuation of the peritoneal surface of both sides dorsal to the V. umbilicalis on the liver occurs on the gall bladder.7. Dorsocaudal to the mesocardium and at right of the mesogastrium ventrale there is a peritoneal surface of the liver which belongs to bursa omentalis. The bursa omentalis opens to the right candalward. The right wall of this bursa is the caudal mesenchymal continuation of the surrounding the right lung bud tissue. This continuation is the Broman's socalled mesolaterale.8. The ductus venosus in the liver runs at first left and ventralward to the central part, then turns ventrocaudal and it becomes V. umbilicalis a little leftward inclined. In the middle of the liver branches V. portae dorsal rightward which runs through the right lobe to its medial surface. After a little continuation on the medial surface of the right lobe it turns into the mesogastrium ventrale and then caudalward dorsal to the duodenum.9. At this beginning of the development of the liver the righl lobe is larger than the left. This separation of the sides can be identified by the furrow of the adhesion of the mesogastrium ventrale.