Dissection
Human dissections were carried out by the Greek physicians Herophilus of Chalcedon and Erasistratus of Chios in the early part of the third century BC. During this period, the first exploration into full human anatomy was performed rather than a base knowledge gained from 'problem-solution' delving. While there was a deep taboo in Greek culture concerning human dissection, there was at the time a strong push by the Ptolemaic government to build Alexandria into a hub of scientific study. For a time, Roman law forbade dissection and autopsy of the human body, so physicians had to use other cadavers. Galen, for example, dissected the Barbary macaque and other primates, assuming their anatomy was basically the same as that of humans.
Mesentery
Mesentery has been known for thousands of years, however it was unclear whether mesentery is a single organ or there are several mesenteries. The classical anatomical description of the mesocolon is credited to British surgeon Sir Frederick Treves in 1885, although a description of the membrane as a single structure dates back to at least Leonardo da Vinci. Treves is known for performing the first appendectomy in England in 1888; he was surgeon to both Queen Victoria and King Edward VII. He studied the human mesentery and peritoneal folds in 100 cadavers and described the right and left mesocolons as vestigial or absent in the human adult. Accordingly, the small intestinal mesentery, transverse, and sigmoid mesocolons all terminated or attached at their insertions into the posterior abdominal wall. These assertions were included in mainstream surgical, anatomical, embryological, and radiologic literature for more than a century.