Anastomoses are connections between anatomical structures as they occur between blood vessels, nerves, lymphatics and hollow organs and ensure the formation of a bypass loop in the deterioration of one of the composite members.

In surgery, the physician partially artificially creates anastomoses, with a distinction being made between end-to-end, side-to-side and end-to-side anastomoses according to the particular form of this surgical procedure. One of the most common anastomotic-related conditions is portal vein obstruction, which allows the anastomoses in this area to be perfused more than usual, causing the formation of varicose veins in the esophagus or around the navel.

What is the anastomosis?

As an anastomosis, the physician refers to a connection between anatomical structures. Such compounds occur in particular between hollow organs, blood and lymph vessels, but also play a role for nerves. For example, blood vessels only form anastomoses with other blood vessels, and lymphatic vessels exclusively connect to nerves.

Also artificially produced compounds sometimes refer to surgery as anastomoses, such as the surgically restored continuity of the gastrointestinal tract following resections of individual sections of the stomach or intestine. However, the surgical repair of nerve connections is associated with the artificial production of anastomoses. As a rule, natural anastomoses are differentiated by organ.

Surgical anastomoses, on the other hand, are differentiated by their shape. The distinction between organs results in subgroups such as vascular anastomoses, intestinal anastomoses or ureteranastomoses. Differentiation by shape gives rise to groups such as end-to-end anastomosis, end-to-side anastomosis, or side-to-side anastomosis.

Anatomy & Construction

The anatomy of an anastomosis depends strongly on its tasks and thus differs according to the particular organ or the anatomical structures by which they are connected. In the lymphatic system, for example, anastomoses connect the lymphatic vessels of the same level.

An example of an anastomosis between blood vessels, however, is the corona mortis, which is naturally abnormally strong and connects the Arteria epigastrica inferior with the Arteria obturatoria. Reconstructed differently is the Riolan anastomosis. This inconstant vascular connection lies in the large intestine between the arteria colica media, the superior mesenteric artery, and the arteria colica sinistra. It is even more complex than the corona mortis and plays a role especially in arterial occlusions of the colon.

In connection with nervous anastomoses, especially the anterior region of the lower jaw should be mentioned, where ever the nerves of the jaw sides are in connection with each other. Artificial anastomoses can be either end-to-end, side-to-side or end-to-side, meaning their anatomy is even more different. For example, in end-to-end anastomost, the surgeon joins two sections of a hollow organ at their open ends.

In end-to-side connections, he instead sews a hollow organ section to another section which he has laterally opened. In an artificial side-to-side anastomosis, in turn, two portions of a hollow organ are opened laterally to be sutured together.

Function & Tasks

One of the most important tasks of anastomosis is the formation of bypasses. This is especially true for anastomoses between vascular structures, such as the riolan anastomosis. This compound secures arterial blood flow in the large intestine by bypassing the bloodstream from the clogged artery to another artery. Thus, anastomoses between arterial structures regulate the circulation and, above all, prevent necrosis, which would cause tissue to die if there is insufficient blood flow.

Also, anastomoses between nerves may form bypasses. They thus ensure the transmission of stimuli and thus the functional processes in the nervous system. An example of such anastomosis is the Jacobson anastomosis. Anastomoses of the diversion also serve in the lymphatic system. For example, if the lymphatic flow in one plane is interrupted by vessels, the anastomoses divert the lymph into an adjacent lymphatic vessel. In this way, the connections prevent lymphoedema in the event of a flow interruption.


Especially with arterial anastomoses can be associated with high disease value. This is especially true in arteriovenous malformations, ie congenital malformations of the blood vessels. As part of such malformations arteries are sometimes directly associated with veins, which can have many threatening consequences.

In connection with morbid anastomoses, the portal vein is often stagnated, as a result of which the portocaval anastomoses are perfused more than usual. It can cause varicose veins in the esophagus, which are particularly risky. Rarely, this phenomenon also causes the formation of varicose veins in the navel. A relatively common disease is also atypical anastomoses in the placental vessels. This phenomenon is sometimes the cause of the fetofetal transfusion syndrome, which may affect identical twins.

In multiform twins, atypical anastomoses in the placenta can lead to the exchange of hormones between the fetuses. If the two fetuses are of different sex, hormonal exchange may interfere with the development of reproductive organs in the female fetus. Apart from those mentioned, anastomoses may also be associated with many other complaints, such as, for example, faecal incontinence in an ileal pouch-anal anastomosis. Except for those mentioned, just about all other anastomotic diseases are rather to be understood as rarities and are therefore not presented in detail.

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