Anastomosis
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An anastomosis (plural anastomoses) refers to a form of network in which streams both branch out and reconnect. For instance, conventional accounts of evolutionary lineage present themselves as the simple branching out of species into novel forms. Under anastomosis, species might recombine after initial branching out, such as in the case of recent research which shows that humans and chimpanzees may have interbred after an initial branching out.Genetic evidence for complex speciation of humans and chimpanzees, 2006
A second case in which the idea of anastomosis finds application is in the theory of Symbiogenesis, in which the emergence of new forms of life (species) are seen to be emergent from the formation of novel symbiotic relationships.
In medicine, anastomosis is the surgical connection of two structures.Medical Terminology Systems: A Body Systems Approach, 2005 It commonly refers to connections between blood vessels or connections between other tubular structures such as a loops of intestine. For example, when a segment of intestine is resected, the two remaining ends are sewn or stapled together (anastomosed), and the procedure is referred to as an intestinal anastomosis.
Circulatory anastomoses
Anastomoses occur normally in the body in the circulatory system, serving as backup routes for blood to flow if one link is blocked or otherwise compromised. There are many examples of these in the body. However clinically important examples include:
- Circle of Willis (in the brain)
- scapular anastomosis (for the subclavian vessels)
- joint anastomoses - clinically very important. Almost all joints receive anastomotic blood supply from more than one source. Examples include knee (and geniculate arteries), shoulder (and circumflex humeral), hip (and circumflex iliac) and ankle.
- pelvic anastomoses
- abdominal anastomoses
- hand and foot anastomoses (which include the palmar and plantar arches)
- Coronary: anterior and posterior interventricular arteries of the heart
Coronary
Coronary anastomoses are a clinically vital subject: the coronary anastomosis is the blood supply to the heart. The coronary arteries are vulnerable to arteriosclerosis and other effects. Inadequate supply to the heart will lead to chest pains (angina) or a heart attack (myocardial infarction).
Coronary anastomoses are anatomically present though functionally obsolete. There was some suggestion that they may be helpful if a problem develops slowly over time (this will need to be verified) but in the case of the pathogenesis of CHD they do not provide a sufficient blood flow to prevent infarction.
Surgical anastomoses
Others
A pathological anastomosis can result from trauma or disease and may involve veins, arteries, or intestines. These are usually referred to as fistulas. In the cases of veins or arteries, traumatic fistulas usually occur between artery and vein. Traumatic intestinal fistulas usually occur between two loops of intestine (enetero-enteric fistula) or intestine and skin (enterocutaneous fistula).Footnotes
References
- Patterson, N. et al. (2006) ["Genetic evidence for complex speciation of humans and chimpanzees"] Nature advance online publication 17 May 2006 doi:10.1038/nature04789.. . , " class="plainlinksneverexpand">[}}#endnote_]}" name="}#endnote_]}" class="citation">Gylys, Barbara A. and Mary Ellen Wedding. Medical Terminology Systems. F.A. Davis Company, 2005.
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