Transcription
In this session, we will discuss about blood vessels, lymphatics, and nerves of the pelvis. The major artery of the pelvis and perineum is the internal iliac artery on each side. In addition to providing a blood supply to most of the pelvic viscera, pelvic walls and floor, and structures in the perineum, including erectile tissues of the clitoris and penis, this artery gives rise to branches that follow nerves into the gluteal region of the lower limb.
You know that the abdominal aorta is the more important and major artery in the abdomen. The abdominal aorta, at the level of the inferior border of L4, divides into two main branches: right common iliac and left common iliac. Each common iliac artery descends and, at the level of the superior border of the sacroiliac joint, divides into two branches: external iliac and internal iliac. The external iliac descends at the level of the pelvic brim or pelvic inlet or superior aperture of the pelvis and, after going posterior to the inguinal ligament, enters into the thigh and becomes the femoral artery. The external iliac artery becomes the femoral artery, but the internal iliac artery is the major artery of the pelvis and perineum. It descends on the lateral wall of the pelvis and, at the level of the superior border of the greater sciatic foramen or greatest sciatic notch, divides into two trunks: anterior trunk and posterior trunk.
Anterior and posterior trunks. You see here in this picture, this is the abdominal aorta. This is the abdominal aorta. Can you see this character? Yes. Thank you. This is the abdominal aorta. The abdominal aorta is on the posterior wall of the abdomen, anterior to the vertebral column. At the level of T12, the thoracic aorta becomes the abdominal aorta. At the level of T12, in the diaphragm, the aorta passes through the diaphragm and becomes the abdominal aorta. The abdominal aorta, at the level of the inferior border of L4, divides into right and left common iliac arteries. Right and left common iliac arteries, as you see here, from the posterior part of the bifurcation of the abdominal aorta at the level of L4. This artery descends anterior to L5 and anterior to the sacrum. This artery is called the median sacral artery. The name of this artery is median sacral artery. The median sacral artery is a single artery, but the lateral sacral arteries are paired. You see here, this is the median sacral artery, and these two arteries on each side of the median sacral, near to the anterior sacral foramina, medial border of the anterior sacral foramina, these descending arteries are called lateral sacral arteries.
Another artery from the abdominal aorta is the ovarian artery or testicular artery in the males, testicular artery, and in the females, ovarian artery. Each ovarian artery or testicular artery originates from the anterolateral surface of the abdominal aorta at the level of L2. At the level of L2, on the right side, the ovarian artery or testicular artery descends anterior to the inferior vena cava and anterior to the psoas major muscle. On the left side, this artery descends anterior to the psoas major and, at the level of L3, at the level of L3, this artery, in the females, ovarian artery, in the males, testicular artery, has a crossing with the ureter. Has a crossing with the ureter. You see here, crossing between the ovarian artery or testicular artery and the ureter. The ovarian artery, after descending anterior to the psoas major and after passing from the superior pelvic brim, enters into the suspensory ligament of the ovary and then to the broad ligament of the uterus and then passing through the mesovarium and enters into the ovary.
Abdulaziz, you should go out and then come back. If you don't hear my sound, you should go out and then enter the game. Enter the game. Is it clear? Okay. I said the internal iliac artery originates from the common iliac artery on each side, approximately at the level of the intervertebral disc between L5 and S1, and lies immediately medial to the sacroiliac joint. The common iliac and internal iliac artery courses inferiorly over the pelvic inlet and then divides into anterior and posterior trunks, as you see here, anterior and posterior trunks. This division to the anterior and posterior trunk is at the level of the superior border of the greater sciatic foramen or greater sciatic notch. Branches from the posterior trunk contribute to the supply of the lower posterior abdominal wall, posterior pelvic wall, and gluteal region. Branches of the anterior trunk supply the pelvic viscera, the perineum, the gluteal region, and the adductor region of the thigh.
And in the fetus, in the fetus, the placenta, the umbilical artery supplies the placenta. There are three main branches from the posterior trunk of the internal iliac artery. Three main branches from the posterior trunk of the internal iliac artery: the iliolumbar artery. The iliolumbar artery, that you see here, ascends to the lumbar area and iliac fossa and divides into lumbar and iliac branches. This is the iliolumbar artery. Next one is the lateral sacral artery. This is the lateral sacral artery. It descends anterior to the sacrum on the medial border of the anterior sacral foramina. Anterior sacral foramina. And the largest terminal branch of the posterior trunk is the superior gluteal artery. Superior gluteal artery emerges between the lumbosacral trunk and S1 from the superior border of the piriformis muscle, goes to the greater sciatic foramen, and from the superior greater sciatic foramen goes to the gluteal region.
Superior gluteal, or I told you, in your lumbar artery ascends laterally, back out of the pelvic inlet, and divides into a lumbar branch that contributes to the supplying of the posterior abdominal wall, psoas major, quadratus lumborum muscles, and cauda equina via a small spinal branch that passes through the intervertebral foramen between L5 and S1, and an iliac branch passes laterally into the iliac fossa to supply muscles and bone. This artery is the lateral sacral. Usually, two arteries originate from the posterior division of the internal iliac artery and course medially and inferiorly along the posterior pelvic wall. They give off branches that pass into the anterior sacral foramina to supply related bone and soft tissue structures in the sacral canal and skin and muscles posterior to the sacrum. The superior gluteal artery is the largest branch of the internal iliac artery. Superior gluteal is the largest branch of the internal artery and is the terminal continuation of the posterior trunk. It courses posteriorly, usually passing between the lumbosacral trunk and the anterior rami of S1, to leave the pelvic cavity through the greater sciatic foramen above the piriformis muscle and enter the gluteal region of the lower limb.
There are many branches from the anterior trunk of the internal iliac artery. First one is the umbilical artery. The umbilical artery is an artery that opens in the fetus, but the dorsal part of this artery closes after birth. This is the umbilical artery. Next branch is the superior vesical artery. Superior vesical artery. Superior vesical artery usually is a branch of the umbilical artery. Next branch is the inferior vesical artery. In the females, instead of the inferior vesical artery, there is the vaginal artery, and the inferior vesical artery is a branch of the vaginal artery. Another branch is the middle rectal. Next branch is the uterine artery and vaginal artery. This artery from the anterior trunk is the obturator artery. You see here, the obturator nerve from the lumbar plexus and the obturator artery from the anterior trunk of the internal iliac artery. Another artery is the internal pudendal. Next artery is the internal pudendal. The internal pudendal artery leaves the true pelvis inferior to the piriformis muscle, goes out. Okay, can you hear my sound? As this, can you hear my sound? Okay, okay, okay. The internal pudendal artery leaves the true pelvis inferior to the piriformis via the greater sciatic foramen and, after turning around the ischial spine and sacrospinous ligament, enters into the perineum via the lesser sciatic foramen. And the next branch is the inferior gluteal artery.
Okay, you see branches of the anterior trunk of the internal iliac artery: umbilical artery, superior vesical artery, inferior vesical artery, middle rectal artery, uterine and vaginal artery in the females, obturator artery, internal pudendal artery, and inferior gluteal. The first branch of the anterior trunk is the umbilical artery. This is the umbilical artery, which gives origin to the superior vesical artery and then travels forward just inferior to the margin of the pelvic inlet. Anteriorly, the vessel leaves the pelvic cavity and ascends on the internal aspect or posterior aspect of the anterior abdominal wall to reach the umbilicus. You see here, posterior surface of the anterior abdominal wall, and this ligament is called the medial umbilical ligament. This part of the umbilical artery after birth closes and will be a ligament. Okay, and this ligament is called the median umbilical ligament. Here, the medial umbilical ligament from the apex of the urinary bladder. This is the urinary bladder. From the apex of the urinary bladder, a single ligament ascends to the umbilicus. This single ligament on the midline is the remaining of the urachus, and it's called the median umbilical ligament. The median umbilical ligament is single, but the medial umbilical ligaments are paired, from right and left umbilical arteries.
I told you the superior vesical artery originates from the proximal part of the umbilical artery. The superior vesical artery originates from the proximal part or root of the umbilical artery and courses medially and inferiorly to supply the superior aspect of the urinary bladder and distal parts of the ureter. In men, it also may give rise to an artery that supplies the ductus deferens. There is a branch from the superior vesical artery for supplying the inferior part of the ductus deferens or distal part of the ductus deferens. The inferior vesical artery occurs in men and supplies branches to the urinary bladder, ureter, seminal vesicle, and prostate. The vaginal artery in women is the equivalent of the inferior vesical artery in men and descends to the vagina, supplying branches to the vagina and to the urinary bladder and rectum. The vaginal artery and uterine artery may originate together as a common branch from the anterior trunk, or the vaginal artery may arise independently.
Next branch is the middle rectal artery. The middle rectal artery is a branch of the anterior trunk of the internal iliac artery. It courses medially to supply the rectum. The inferior part of the rectum is called the ampulla of the rectum. The vessel anastomoses with the superior rectal artery, that superior rectal artery is a branch of the inferior mesenteric artery, and inferiorly, the inferior rectal artery is a branch of the internal pudendal artery. These three arteries anastomose with each other. Okay, superior rectal artery is a branch of the inferior mesenteric artery, middle rectal artery is a branch of the anterior trunk of the internal iliac artery, and inferior rectal artery is a branch of the internal pudendal artery, that internal pudendal artery is a branch of the internal iliac artery.
Next artery is the obturator artery. It courses anteriorly along the pelvic wall and leaves the pelvic cavity via the obturator canal. You see here, this artery and obturator nerve together with the obturator nerve above and obturator vein below, it enters and supplies the adductor region of the thigh. You see here, this artery is the obturator artery. Other branch is the internal pudendal artery. Internal pudendal artery. The internal pudendal artery courses inferiorly from its origin in the anterior trunk of the internal iliac and leaves the pelvic cavity through the greater sciatic foramen inferior to the piriformis muscle, inferior to the piriformis muscle, goes out from the pelvic cavity via the sciatic foramen in association with the pudendal nerve, in association with the pudendal nerve on its medial side. The vessel passes laterally to the ischial spine and then through the lesser sciatic foramen to enter the perineum. Okay, this artery, internal pudendal artery, and pudendal nerve turn around the ischial spine and sacrospinous ligaments and from the lesser sciatic foramen enters into the perineum. Among the structures it supplies are the erectile tissues of the clitoris and penis. The internal pudendal artery supplies erectile tissues of the penis and clitoris.
Next branch is the inferior gluteal artery. The inferior gluteal artery is a large terminal branch of the anterior trunk. It passes between the anterior rami of S1 and S2 or S2 and S3 in the sacral plexus and leaves the pelvic cavity through the greater sciatic foramen inferior to the piriformis muscle. It enters the gluteal region and contributes to the blood supply of the gluteal region and anastomoses with the network of vessels around the hip joint. The uterine artery is a branch of the anterior trunk of the internal artery in the female. This artery courses medially and anteriorly in the base of the broad ligament of the uterus and reaches the cervix. Along its course, along its course, the vessel crosses the ureter. This structure is the ureter. This is the ureter, and this is the uterine artery. Okay, there is a crossing between the crossing between the uterine artery and the ureter. You see here in this picture, the uterine artery goes medially and anteriorly superior to the ureter. This relationship is at the level of the supravaginal part of the cervix, near to the lateral fornix. Once the vessel reaches the cervix, it ascends along the lateral margin of the uterus, along the lateral margin of the uterus, to reach the uterine tube, where it curves laterally and anastomoses with the ovarian artery. The ovarian artery. The uterine artery is the major blood supply to the uterus and enlarges significantly during pregnancy through anastomosis with other arteries. The vessel contributes to the blood supply of the ovary and vagina as well.
In women, ovarian arteries originate from the abdominal aorta and then descend to cross the pelvic inlet and supply the ovaries. You see here, this is the inferior vena cava, this is the right ovarian artery, and this is the left ovarian artery. This muscle is the psoas major muscle. I told you about this. The anastomosis with the terminal part of the uterine arteries. Ovarian arteries on each side travel in the suspensory ligament of the ovary or infundibulopelvic ligament as they cross the pelvic inlet to the ovary. Branches pass through the mesovarium to reach the ovary and through the mesometrium of the broad ligament to anastomose with the uterine artery. There is anastomosis between the uterine artery and the ovarian artery in the broad ligament of the uterus. Ovarian artery, similar to the uterine artery, enlarges significantly during pregnancy to augment the uterine blood supply.
This artery is the median sacral artery. It originates from the posterior surface of the aorta just superior to the aortic bifurcation. I told you at the vertebral level of L4. It descends in the midline, crosses the pelvic inlet, and then courses along the anterior surface of the sacrum and coccyx. It gives rise to the last pair of lumbar arteries and to branches that anastomose with the iliolumbar and lateral sacral arteries. Do you have any question in this part? Any question? Do you have any question? No. Thank you. Okay. Pelvic veins follow the course of all branches from the abdominal aorta. There are many branches. I will tell next session, inshallah. I will tell about the abdominal aorta. No, the vaginal artery is not equivalent to the inferior vesical in the females. The inferior vesical artery is a branch of the vaginal artery. Okay, the vaginal artery, maybe in some females, the vaginal artery and inferior vesical artery will be separate. They are separate, but in some cases, the inferior vesical artery is a branch of the vaginal artery. I will tell about the abdominal aorta. Abdominal aorta. The abdominal aorta has many branches. The abdominal aorta has many branches, for example, inferior phrenic, inferior phrenic arteries, middle suprarenal, renal arteries, gonadal arteries, testicular or ovarian arteries, four pairs of lumbar arteries, and celiac trunk, superior mesenteric, inferior mesenteric arteries, and posterior to the bifurcation, this is the median sacral artery. I will tell about all of them.
Okay, I told you pelvic veins follow the course of all branches of the internal artery except for the umbilical artery and iliolumbar artery. Iliolumbar vein and umbilical vein. These two veins on each side have different ways from the umbilical artery and iliolumbar artery. Okay, they're all different ways, but other branches have similar ways to the arteries on each side. The veins drain into the internal iliac veins, which leave the pelvic cavity to join the common iliac vein situated just superior and lateral to the pelvic inlet. Lymphatics from most pelvic viscera drain mainly into lymph nodes distributed along the internal iliac and external iliac arteries. Internal lymph nodes and external lymph nodes. These nodes drain into the nodes associated with the common iliac arteries and then into the lateral aortic or lumbar lymph nodes. Lateral aortic or lumbar lymph nodes associated with the lateral surface of the abdominal aorta. In turn, these lateral aortic or lumbar nodes drain into the lumbar trunks, which contribute to the origin of the thoracic duct at approximately vertebral level T12. You know that the cisterna chyli is located at the level of T12 and L1, and these lymph nodes drain into the cisterna chyli and then to the thoracic duct. After 10 minutes rest, we will start again about nerves. 10 minutes rest. Okay, do you have any question? 20. What's the meaning of 20? After 10 minutes rest, we start. No, after 10 minutes rest, just test. 10 minutes.
This small nerve penetrates the coccygeus muscle to enter the pelvic cavity and join with the anterior rami of S4 and a single branch that is called the anococcygeal nerve. Here is the anal nerve. Anococcygeal nerves penetrate the muscles and the overlying sacrotuberous and sacrotuberous ligament and pass superficially to innervate skin in the anal triangle of the perineum, that I will tell about this area. In addition to somatic plexuses, sacral and coccygeal plexuses, that are they are somatic, there are visceral plexuses. The sympathetic chain or sympathetic trunk here is formed by four pairs of sacral ganglia and one single ganglion anterior to the coccyx, that is called the ganglion impar. You see here, this is the sympathetic postganglionic chain, and this is the ganglion impar. You see here the location of this sympathetic chain is medial to the anterior sacral foramina. Medial to the anterior sacral foramina. I told you this is the impar, and these are four pairs, four pairs of sacral ganglia.
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If you cannot hear my sound, go out and then come again, enter again. Okay, I told you four ganglia occur along this trunk. Anterior to the coccyx, the two trunks join to form a single small interterminal ganglion that is called the ganglion impar. The principal function of the postganglionic sympathetic trunk in the pelvis is to deliver postganglionic sympathetic fibers to the anterior rami of the sacral nerves for distribution to the periphery, mainly to parts of the lower limb and perineum.
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You see here, the prevertebral plexus. The prevertebral plexus enters the pelvis as two hypogastric nerves. You see here, between the bifurcation of the aorta and the promontory of the sacrum, anterior to L5, there is a plexus that is called the superior hypogastric plexus. This is the superior hypogastric plexus. From the superior hypogastric plexus, two nerves descend, two nerves descend on each side of the rectum and enter into the pelvis. These nerves are called hypogastric nerves. These are hypogastric nerves. Okay, have a look here. These are hypogastric nerves. Hypogastric nerves are formed by the separation of the fibers of the superior hypogastric plexus into right and left bundles. I told you, the superior hypogastric plexus is situated anterior to the vertebra L4, L5, between the promontory of the sacrum and the bifurcation of the aorta. This is the superior hypogastric, and these are the hypogastric nerves. Hypogastric nerves are joined by pelvic splanchnic nerves. Pelvic splanchnic nerves. You see here, pelvic splanchnic nerves are formed by S2, S3, and S4. S2, S3, and S4 parasympathetic fibers. Of the S2, S3, and S4, and hypogastric nerves make the inferior hypogastric plexus. Inferior hypogastric plexus is located on the floor of the pelvis, superior to the pelvic diaphragm. This is the inferior hypogastric plexus. You see here, inferior hypogastric plexus, one on each side, course in an inferior direction around the pelvic walls, medially to major vessels and somatic nerves. They give origin to the following subsidiary plexuses. You see around the rectum, there is the rectal plexus in both sexes, males and females. Around the bladder, around the urinary bladder, there is the vesical plexus. Around the prostate in the males, there is the prostatic plexus, and around the vagina and cervix, there is the uterovaginal plexus. The prostatic plexus in the males is very important. It's very important and makes innervation of the erectile structures, penis erectile tissues. Innervation of the erectile tissues of the penis is by the prostatic plexus, and the prostatic plexus is a part of the inferior hypogastric plexus. Prostatectomy is a surgery for removing the prostate, removal of the prostate. Okay, it may be necessary to perform radical surgery to cure cancer of the prostate. To do this surgery, the prostate and its attachments around the base of the urinary bladder, including the seminal vesicles, must be removed. Part of the inferior hypogastric plexus in this region gives rise to nerves that innervate the erectile tissues of the penis. In 40% of males, after prostatectomy, impotence may occur if these nerves cannot be or are not preserved during removal of the prostate. For the same reasons, women may experience sexual dysfunction if similar nerves are damaged during pelvic surgery, for example, during a total hysterectomy. Okay, this is the prostatic plexus. Okay, do you have any question? You have any comment? No. Okay, after 10 minutes rest, we will start again. 10 minutes rest.