Vaginal plexus of the abdominal cavity and pelvis

In the abdominal cavity and in the pelvic cavity there are various vegetative nerve plexuses of the largest size, consisting of vegetative nodes and bundles of nerve fibers connecting them. In the vegetative nodes are the bodies of the neurons of the efferent path, the processes of which (postganglionic fibers) are sent from these plexuses to the internal organs and vessels for their innervation.

One of the largest vegetative plexuses of the abdominal cavity is the abdominal aortic plexus located on the aorta and continuing on its branch.

The largest and most important in the structure of the abdominal aortic plexus is the celiac plexus (plexus coeliacus), or, as it is also called, the solar plexus, or the "brain of the abdominal cavity." The celiac plexus is located on the anterior surface of the abdominal part of the aorta around the celiac trunk. It consists of several large nodes (often five) and numerous nerves connecting these nodes. The composition of the celiac plexus includes two semilunar forms of the celiac node, located to the right and left of the celiac trunk. The left celiac node is attached to the aorta, the right - to the lower surface of the liver, in front - to the head of the pancreas. As part of the celiac plexus, there are two aortic nodes, each of which is located at the point of departure from the aorta of the corresponding renal artery, as well as the unpaired superior mesenteric node lying at the origin of the same artery. The right and left large and small thoracic internal nerves, lumbar internal nerves from the lumbar nodes of the sympathetic trunk approach the celiac plexus. To the celiac plexus are suitable, but pass through its nodes in transit of the fibers of the posterior trunk of the vagus nerve, as well as the sensitive fibers of the right diaphragmatic nerve. From the nodes of the celiac plexus nerves that contain already postganglionic sympathetic nerve fibers and preganglionic parasympathetic from the branches of the vagus nerve, which alone or together with the vessels are directed to the organs, depart from the nodes of the celiac plexus. Located around the vessels, the nerves form the so-called circulatory (periarterial) vegetative plexuses, and in the interior of the internal organs - intraorganic vegetative plexuses.

Numerous vegetative (sympathetic) fibers go along the celiac trunk and its branches, forming the same plexuses around the common hepatic, splenic, left gastric arteries and their branches. Organ plexuses of the parenchymal organs are located not only around the blood vessels, but also in the connective tissue stroma of the organs. As a result, the gastric plexus (plexus gastrici), the splenic plexus (plexus lienalis), the hepatic plexus (plexus hepaticus), the pancreas-duodenum plexus (plexus pancreaticus) and others form.

The nerve plexuses of the hollow internal organs: the stomach, the small and large intestine, as well as the urinary and gallbladder, etc. - lie between the layers of the walls of the organs. Thus, a subserous, intermuscular and submucosal plexus is isolated that effect the innervation of the muscles of the walls of the organs and glands. From each celiac node branches branch to the adrenal glands, forming a paired adrenal plexus (plexus suprarenalis). In the adrenal vegetative branches there are preganglionic sympathetic fibers innervating the medulla of the adrenal gland. Thus, the adrenal medulla having a common origin with the nodes of the autonomic nervous system, unlike any other organs, receive innervation directly from the preganthionic sympathetic nerve fibers, which end with effector nerve endings on the secretory cells of the medulla.

The abdominal aortic plexus (plexus aorticus abdominalis) is a direct continuation of the celiac plexus. This plexus is a plate of nerve fibers and nodes, located on the front surface of the aorta from the celiac trunk and to the superior mesenteric artery, and even to the inferior mesenteric artery. At the level between the two mesenteric arteries, this plexus is called the intergranular plexus (plexus intermesentericus).

The abdominal aortic plexus delivers thin branches to the renal vessels, in whose adventitia the paired renal plexus is formed (plexus renalis). In the formation of the renal plexus, the branches of the upper lumbar region of the sympathetic trunk, as well as preganglionic parasympathetic fibers from the branches of the right vagus nerve, participate. In the renal plexus one or two fairly large renal nodes (ganglia renalia) and a large number of small nodes are constantly found. Large renal nodes are located in front and below the renal artery. Sympathetic fibers of the renal plexus along the branches of the same artery penetrate into the kidney, and also pass to the ureter, participating in the formation of the ureteric plexus (plexus uretericus).

The branches of the abdominal aortic plexus are accompanied by the blood vessels of the gonads. In men along the testicle arteries there is a paired testicular plexus (plexus testicularis). In women along the ovarian arteries, the paired ovarian plexus (plexus ovaricus) also descends into the small pelvis.

The branches of the superior mesenteric node, as well as of the abdominal aortic plexus, pass to the superior mesenteric artery, forming the superior mesenteric plexus.

The superior mesenteric plexus (plexus mesentericus superior) is located at the base of the superior mesenteric artery, at level I of the lumbar vertebra, as well as in the adventitia of this large blood vessel. This plexus continues on the intestinal and colon arteries, reaches the thin, blind, ascending and transverse colon of the intestines, in the walls of which there are serous, muscular-intestinal and under the mucous plexus.

Continuation of the abdominal aortic plexus is the inferior mesenteric plexus (plexus mesentericus inferior). In this plexus also come branches from the upper lumbar nodes of the sympathetic trunk. On the branches of the inferior mesenteric artery, the nerves of this plexus reach the sigmoid, descending and left half of the transverse colon and in their walls form a subserous, musculoskeletal and submucous plexus. From the lower mesenteric plexus originates the upper rectal plexus (plexus rectalis superior), accompanying the same artery.

The abdominal aortic plexus extends to the common iliac artery in the form of the right and left iliac plexus (plexus iliaci), and also gives off several rather large nerves that pass into the upper hypogastric plexus (this plexus is located on the anterior aorta and below its bifurcation , on the bodies of the lower lumbar vertebrae and on the sacrum.The upper hypogastric plexus consists of flat bundles of nerve fibers.This plexus is also suitable for the internal nerves from the lower lumbar and the three upper crosses right nodes and left sympathetic trunks.

Somewhat below the Cape of the sacrum, the upper hypogastric plexus is divided into two bundles - the right and left hypogastric nerves, united by the name "pelvic plexus". Behind the peritoneum hypogastric nerves descend into the cavity of the small pelvis and form a paired lower hypogastric plexus.

The lower hypogastric plexus (plexus mesentericus inferior) consists of bundles of vegetative fibers descending into the small pelvis from the upper hypogastric plexus, as well as from the branches of the sacral region of the sympathetic trunks and fibers of the pelvic (parasympathetic) internal nerves. The right and left lower hypogastric plexuses are located on the back wall of the small pelvis. The medial part of each lower hypogastric plexus in men is attached to the lateral surface of the ampulla of the rectum, in front comes to the seminal vesicle. The plexus continues on the bladder and the prostate gland in the form of the plexus vesicalis, the prostate plexus prostaticus, the plexus deferentialis plexus and other organ plexuses. In women, the lower hypogastric plexus is also located on the sides of the rectum, in front reaches the cervix and vaginal artery - forms utero-vaginal plexus and passes to the bladder. The lateral edge of the lower hypogastric plexus reaches the large vessels of the small pelvis.

The nodes of the lower hypogastric plexus have a different size and shape. Apart from the nodes, there are many individual neurons in the nerve bundles.