 In Part 1, the male pelvic plexus will be dissected. Due to the continuity of the pelvic plexus and abdominal autonomic nerves, first we will dissect the abdominal structures. The peritoneal cavity is opened, revealing the abdominal organs. By inserting hands behind the ascending colon, we can peel off the fusion fascia behind the ascending mesocolon and the right side intestines become movable. The liver is fixed to the abdominal wall and connected to the inferior vena cava via the hepatic veins. In order to obtain a clear view, the hepatic veins are cut and the liver becomes freed and is then movable. Now the liver can be dislocated. After shifting the digestive organs, the right kidney enclosed in its fascia is dissected. The renal fascia includes not only the kidney, but also blood vessels and the ureter. This fascia facilitates tracing the ureter within the pelvis. Within the renal fascia, the testicular blood vessels are also included. These blood vessels descend slightly obliquely. We can easily trace these vessels seen through the fascia. By pulling the testis and spermatic cord, the superficial inguino ring can be seen. At the superficial inguino ring, scissors are inserted to open the inguino canal, freeing the spermatic cord. Between the testicular vessels and the doctus deferens, there is a thin fascial sheet, provisionally called the testiculodeferential fascia. Lateral to this fascia, we see the cord of the umbilical artery and another fascia. Here, the right hip bone has been removed and the fascial stratification will be demonstrated layer by layer. The levator ante muscle has been reflected laterally. Note the fascia which lies superior and medial to the levator ante. This is called the superior fascia of the pelvic diaphragm. As shown by the inserted forceps, the upper part of this fascia is free and does not adhere to the visceral fasciae. However, at the level of the middle of the prostate, this fascia continues downwards and tightly adheres to the fascia of the prostate. And tracing further downwards, it continues to the lower part of the prostate. We will cut the superior fascia of the pelvic diaphragm just above this line of adherence. In order to view the fascia layers from inside, we will return the previously seen fascia of the testicular vessels. The innermost layer is the peritoneum. This is the aforementioned testiculodeferential fascia which stretches between the testicular vessels and the ductus deferens. Between this fascia and the cord of the umbilical artery, another fascia is found. This is the fascia of the ureter. Within this fascia, the hypogastric nerve is included. Later we will be able to see this enveloped hypogastric nerve. The cord of the umbilical artery originates from the internal iliac artery, passes by the urinary bladder and ascends to the navel. The membranous structure which hangs from this cord is called the vesicle hypogastric fascia. After cutting the artery of the ductus deferens, which runs within this fascia, the fascia of the ureter can be easily separated. Within the vesicle hypogastric fascia, various branches of the internal iliac vessels run. Here is the levator ante and the portion of adhesion of the superior fascia of the pelvic diaphragm with the prostatic fascia. Outside the levator ante lies the pudendal nerve and in between is the inferior fascia of the pelvic diaphragm. Now we will examine the nerves. After reflection of the levator ante, its supplying nerves can be seen. Near the nerve to the levator ante, several thin nerve branches can be seen. These are pelvic splenchnic nerves. To examine these, first we identify and cut the blood vessels. The sympathetic components of the pelvic plexus are the minor sacral splenchnic nerves from the sacral sympathetic trunk and the dominant hypogastric nerves from the lumbar sympathetic trunk via the superior hypogastric plexus in front of the aorta. The parasympathetic components are the pelvic splenchnic nerves from the sacral plexus. For pelvic dissection, an absorbent cloth is used to blot the residual fluid. Now we will examine the composition of the pelvic plexus. From the lower end of the sacral plexus, the pudendal nerve originates. By tracing the pudendal nerve, we find that this nerve consists of the inferior rectal nerves and the dorsal nerve of the penis between these, the perineal nerves. The internal pudendal artery accompanies the pudendal nerve. With the levator ante reflected inferior laterally, the supplying nerve clearly comes into view. Close to the origin of this nerve, several thin pelvic splenchnic nerves are dissected. Interestingly, the pelvic splenchnic nerves, the pudendal nerve, and the nerve to the levator ante all originate in close proximity. With the pelvic organs pulled to the front, you can clearly see these nerves and their intimate origin from the sacral plexus. Now, to examine the sympathetic component, as we ascend towards the abdominal aorta and close to the bifurcation of the aorta, we see that the superior hypogastric plexus descends. Also slightly superior to the bifurcation, the origin of the inferior mesentery artery can be seen. The sympathetic components descend from the right and left lumbar sympathetic trunks and unite in front of the abdominal aorta to form the superior hypogastric plexus. These nerves intermingle with the lymphatic plexus surrounding the abdominal aorta. The parasympathetic and also sympathetic components unite to form the pelvic plexus and numerous branches are distributed to the internal organs. However, some branches from the hypogastric nerve directly reach the ureter and the ductus deferens and the lower most pelvic's blankening nerve branches descend in the groove between the prostate and rectum to reach the penis. Some branches from the hypogastric nerve directly reach the lower extremity of the ureter and together with the ureteric branches from the pelvic plexus, they form a loop around the lower end of the ureter. Numerous branches to the bladder and those to the prostate are also dissected. A descending nerve which runs between the rectum and the prostate is also dissected. We will trace this nerve to its destination. The pelvic plexus of this specimen is well developed. We will reconfirm the numerous branches which are distributed to the bladder and prostate. Direct branches from the pelvic's blankening nerves and the lower most branches of the pelvic plexus unite behind the prostate. From this union, several fine branches originate. One of these branches is distributed between the ureter and the pelvic plexus which is attached to and supports the prostate. Another thin branch descends between the prostate and the pelvic plexus and reaches the cavernous portion of the penis. This is the so-called cavernous nerve of the penis. In addition to these nerves, several fine branches are detected. These are thought to reach the dorsum of the penis. However, these are too thin to trace the region and distribution of the right pelvic plexus has been examined. To observe the left pelvic plexus, first we will examine the aortic plexus from the right. Most autonomic branches from the ciliac plexus run along the inferior mesenteric artery and join the inferior mesenteric plexus. However, the superior hypogastric plexus is formed by the right and left lumbar splenchnic nerves which originate from the lumbar sympathetic trunks. There is some communication between this plexus and the inferior mesenteric plexus. The superior hypogastric plexus again bifurcates into the right and left hypogastric nerves within the pelvis. Now, with a specimen in the reverse direction, we will dissect the left side. The cut end of the inferior mesenteric artery is reflected in order to view the bifurcation of the superior hypogastric plexus into the right and left hypogastric nerves. The bifurcation between the superior hypogastric plexus and the inferior mesenteric plexus is also observed. Now, we will trace the left hypogastric nerve and dissect the pelvic plexus. The left hypogastric nerve crosses the ureter inferiorly to reach the pelvic plexus. Now, we will examine the sacro plexus. The pudendal nerve runs around the cut end of the sacrospinus ligament. Close to the origin of the pudendal nerve, the pelvic plank nerve originates from S3 and S4 and joins the pelvic plexus. In this specimen, some pelvic plank nerves cross over the pelvic plexus to directly reach the ureter. Also from the hypogastric nerve, there are some direct branches to the ureter. In this specimen, branches to the lower part of the ureter tend to be independent. Numerous branches are distributed to the bladder and prostate. The lower most branch descends between the prostate and the rectum to reach the dorsum of the penis. Now, we will perform a median section in order to dissect from the inside. We sectioned the urogenital organs and the anterior wall of the rectum, but left the posterior wall of the rectum intact. With the rectum pulled anteriorly, we will examine the parasympathetic components which form the pelvic plexus. From the sacro plexus, numerous pelvic plank nerves, which originate from S3 and S4, contribute to the formation of the pelvic plexus. There is a small contribution from S2. From the pelvic plexus, several branches are distributed to the rectum. From this plexus, numerous branches are distributed to the urogenital organs. Branches reach the ureter, the ductus deference, and the seminal vesicle, as well as the prostate. The lower most prostate branch also gives a twig to the rectum and then descends to the cavernous body of the penis. By pulling the bladder and prostate anteriorly, we will examine these same nerve branches from the outside. These branches are divided into three groups. The upper branches are distributed to the ductus deference, ureter, and the upper part of the bladder. The middle branches are distributed to the bladder, the neck of the bladder, and the prostate. The lower branches descend along the posterior lateral border of the prostate and reach the penis and the levator ante. We note one independent pelvic splanchnic nerve which directly reaches the penis and levator ante. The upper most and lower most urogenital branches run independent of the pelvic plexus. However, most of the urogenital supply is from the middle branches which run via the pelvic plexus. Therefore, the branches to the urgans are not uniform. With the rectal halves opened, the origin of the pelvic splanchnic nerves from the lower part of the sacral plexus is clearly seen. Another sympathetic component of the pelvic plexus is the sacral splanchnic nerves which originate from the sacral sympathetic trunk. As these were not detected in specimens 1 and 2, we will examine the median sectioned pelvis of specimen 3. All internal urgans of the pelvis have been median sectioned including the posterior wall of the rectum. Medial to S2 and S3, you can see the thin sympathetic trunk descending longitudinally. Here are S1, S2, S3 and S4. At the level of S4 from the sympathetic trunk, a sacral splanchnic nerve originates and then joins the pelvic plexus. This is a direct branch from the hypogastric nerve which joins a few branches from the pelvic plexus to supply the ureter and ductus deferens. Branches of the upper half of the pelvic plexus are distributed to the bladder. Those of the lower half of the pelvic plexus are distributed to the prostate and the rectum. We have demonstrated the composition and distribution of the male pelvic plexus in 3 pelvic halves. The female pelvic plexus will be dissected. Here in a female specimen we will examine the pelvic plexus with the right hip bone removed via lateral step-by-step dissection. From the sacral plexus we will trace the pudendal nerve and vessels between the sacrotuberous ligament and the sacrospinous ligament. The pudendal nerve and vessels reach the glitterous under the pubic symphysis. Outside the levator ante is the inferior fascia of the pelvic diaphragm. Just outside this fascia we dissect the pudendal nerve and its branches. Here is the inferior rectal nerve, the perineal nerves and also the dorsal nerve of the glitterous. We can see the unique S-shaped course of the dorsal nerve of the glitterous. Returning to the abdominal cavity now we will enter the retroperitoneal space and trace into the pelvic cavity. We cut the large intestine close to the left colic flexure and pull the small intestine and right colon to the upper right and the left colon to the lower left. Now we can easily enter the retroperitoneal space. We can see the renal fascia. Holding the right and left kidneys and the renal fascia you can see that the renal fascia also includes the aorta and inferior vena cava and extends to the pelvic cavity. We will trace this fascia into the pelvic cavity. We cut the ovarian vessels so that the right ovary is movable and we can trace the renal fascia behind the peritoneum. The peritoneum and a fascial sheet have been separated. This fascial sheet includes the ureter. If we pull this fascia we can see the iliac vessels and the sheath which wraps them. These two fascial sheets are separable. We will carefully dissect this fascia including the ureter. Just below the bifurcation of the aorta it is revealed that the superior hypogastric plexus and the right and left hypogastric nerves are also included in this fascia. Provisionally we will call this fascia the ureteral hypogastric fascia. The ureter and its fascial sheath are reflected. The internal iliac artery is included in a fascial sheath. This vascular sheath continues to the cord of the umbilical artery and forms a vesicle hypogastric fascia. Looking at the circular fascial stratification inside the vesicle hypogastric fascia is the fascia of the ureter and the innermost fascia is the fascial sheath which includes the ovarian vessels and inside is the peritoneum. Looking again at the pelvic sidewall, first you can see the levator ante muscle sandwiched between the upper and lower fascia of the pelvic diaphragm. Medial to the levator ante muscle the supplying nerve of this muscle is dissected. If we follow this nerve proximally, we can reach the sacroplexus close to the origin of the pudendal nerve. Pulling the cord of the umbilical artery, you can see numerous branches which run within this fascia to the pelvic organs. Within this fascia, some thick veins are found. These veins are cut to obtain a clear view of the arteries. By tracing these arterial branches of the internal organs, we find that they originate close to the bifurcation of the internal iliac artery into the umbilical artery and the inferior pudendal artery. The superior fascia of the pelvic diaphragm covers the levator ante. To facilitate dissection of the pelvic plexus, we will peel this fascia from the fascia of the bladder. The arteries within the vesicle hypogastric fascia will be cut in order to view the pelvic plexus. The pelvic plexus consists of sympathetic nerves which descend from the lumbar sympathetic trunks and parasympathetic components which originate from the sacral plexus. From the pelvic plexus, branches are distributed to the rectum, uterus, vagina, lower most ureter, bladder, and urethra and also to the dorsum of the clitoris. Some independent branches do not run via the pelvic plexus. Near the bifurcation of the aorta, we can see the superior hypogastric plexus. This plexus consists of the lumbar splanknic nerves from the right and left sympathetic trunks. We trace from the superior hypogastric plexus to the right hypogastric nerve. By displacing the ureter we can see that the hypogastric nerve continues to the pelvic plexus. Again returning to the broad view, we will trace from the hypogastric nerve downward. The pelvic splanknic nerves are the parasympathetic component. Tracing these nerves forward we find that they enter the pelvic plexus lateral to the rectum. Now we will trace the branches of the pelvic plexus. Looking at the upper group of branches we find that they are distributed to the lower most ureter and to the bladder as well as to the transitional area between them. By pulling the ureter, we can confirm this pattern of distribution. In this specimen, some of these branches descend directly from the hypogastric nerve and do not run via the pelvic plexus. Therefore, it seems that the hypogastric nerve is dominant. Before examining the lower pelvic plexus branches, we will trace the pudendal nerve and the nerve to the levator ante. Here the levator ante directly attaches to the vagina and rectum. By separating these structures, we note that branches of the lower group of the plexus are distributed to this area. If we enter deep to the levator ante, we can further trace these lower branches which run on the rectal wall. These lower group nerves are distributed to the rectum, vagina and the anterior end of the levator ante and possibly to the dorsum of the clitoris. However, due to the thinness of these branches, they are difficult to trace and identify their termination. Now we will look at the pelvic plexus of the left side with the head directed to the right. Here we grasp the pudendal nerve and then reflect the levator ante laterally. The nerves of supply to the levator ante enter its upper surface. Medial to these nerves, the pelvic's blank neck nerves are dissected. After median sectioning, the internal organs are reflected in order to view from the medial side. After cutting the inferior mesenteric artery and pulling the rectum forward, the curved hypogastric nerve becomes straight. In this specimen, in addition to the epigastric nerve, two sacral blank neck nerves originate at the level of S2. As to the parasympathetic component, the pelvic's blank neck nerves originate from S3 and S4. In general, the pelvic plexus in females does not seem to be as well developed as that in males. Looking closely at the distribution, we can see branches to the lower most part of the ureter, as well as those to the uterus and vagina. By separating the bladder and the uterus, we can see several intermediate branches. Again, looking from outside, we see that these branches seem to supply both organs. These branches first give off twigs to the uterus and vagina and then run forward to reach the bladder. Unfortunately, in this specimen, the tissues were rather stiff and it was difficult to separate and trace the branches. A further detailed examination could not be undertaken. Looking overall at the left pelvic plexus branches, just as in the right plexus, in the upper distributing branches, the hypergastric nerve is dominant. While among the lower branches, the pelvic's blank neck nerve is dominant. We have demonstrated the composition and distribution of both sides of the female pelvic plexus in one specimen.