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(1) In botany, an opening in the cell membrane of a vessel in vascular plants. Water passes freely through the perforations and into the vessels. The perforations may be on the lateral and transverse walls of the cells. If a perforation is single, it is called a simple perforation (in the vessels of oaks and herbs). Multiple perforations are arranged in parallel series (scalariform perforations), in an irregular network (reticulate perforations), or as a group of approximately circular holes (foraminate perforations). Ferns have scalariform perforations, ivies reticulate perforations, and ephedras foraminate perforations.
(2) In medicine, the penetration of the wall of a hollow or tubular organ, for example, the intestine.
in medicine, an opening or hole in the wall of a cavitary or tubular organ, as a result of which the cavity of the organ communicates with surrounding cavities or tissues.
Perforation may be caused by intrusion of a foreign body from the lumen of an organ (for example, perforation of the esophagus by a swallowed bone) or externally (a penetrating knife or bullet wound). It may also be caused by disruption of all layers of an organ by a pathological process, for example, perforation of an ulcer or tumor of the stomach or intestine or perforation of the vermiform appendix or the gallbladder with gangrenous appendicitis or cholecystitis.
When there is a perforation, the contents of a hollow organ, by penetrating surrounding tissue (periesophageal or perirectal) or the abdominal cavity, cause development of a rapidly progressing purulent inflammatory process called mediastinitis, paraproctitis, or peritonitis. Treatment consists in emergency surgery.