Special anatomy and histology: in two volumes (Volume 2).

  • Horner, William E. (William Edmonds), 1793-1853.
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: Special anatomy and histology: in two volumes (Volume 2). Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    but thought that the action of the pancreas if it were exterminated would easily pass to them,* hence his appellation to them of Pancreas Secundarius. The Jejunum and Ileum form the remaining length of the small intestine, and have no external marks of difference from each other. They are strung along the mesentery, and, in consequence of their great length, are thrown into folds or convolutions, which give to them a complicated appearance. There is, however, no difficulty in tracing them regularly from one end to the other. They occupy the umbilical, the hypogastric, and a part of the iliac regions, and are surrounded by the circuit of the colon. The upper two-fifths is the jejunum, and the lower three-fifths, the ileum. This distinction, originally introduced by Galen,f from a supposition that the jeju- num was more frequently found empty than any other intestine, has no rigid anatomical support. The only difference between the two is, that the valvulae conniventes, existing as they do in the whole length of the jejunum, become less abundant at the upper part of the ileum, and finally disappear entirely towards its lower extremity. They decrease indeed very sensibly at the lower part of the jeju- num, and sometimes there are none at all in the ileum. In an ob- servation made carefully on this matter by detaching the intestine from the mesentery—inverting it and then measuring, I found the valvulse conniventes to cease as near as may be, in the middle of the length of the mesenteric portion of the intestinal canal. The above distinction into jejunum and ileum has been rejected by the most approved modern authorities, such as Haller, Soemmering, and Meckel. It sometimes happens, that the intestinum tenue has one or more blind pouches like cseca appended to its sides and opening into its cavity. The small intestine is supplied with blood from the superior me- senteric artery. Its nerves come from the sympathetic. The Mesentery (Mesenterium) is a process of peritoneum which serves, as mentioned, to connect the intestinum tenue to the poste- rior parietes of the abdomen, and extends its connexions from the left side of the second lumbar vertebra to the right iliac fossa. This attachment, called the root, is about six inches in length ; whereas, intestine, are evidently different from these in being more spherical, always solitary, and small in comparison. * Id. p. 291. f Portal, Anat. Med.