Reduplication of swine spleen lobes

In a search for the reduplication of the spleen, a total of 227,513 swine from 130 breeders were surveyed at a slaughterhouse (Ozu Health Center, Ehime Prefecture, Japan) between October 1993 and June 1995. They were 6 to 7 months old and their body weight ranged from 95 to 120 kg. Twenty swine had two lobed spleens. Of these, nine were males and 11 were females. The second or sub-lobe was generally smaller than the main lobe but was variable in size. Large ones were similar in size to the main lobe and small ones were approximately 1/4 of the length of the main lobe. One very small lobe was just a protrusion of the main one across the greater omentum. The two lobes were always attached to each other in the central portion, and fat and the greater omentum were always found between the lobes. The splenic artery, vein and nerve were shared between the two lobes. The main lobe was covered with peritoneum from the parietal surface of the stomach while the sub-lobe was covered with visceral peritoneum. Both peritonea joined to the greater omentum at the hilus in ordinary spleens, but at short distance from the hilus in double lobed spleens.