THE PELVIS VASCULAR AND NERVOUS SYSTEM SOMATIC AND AUTONOMIC NERVES

Transcription

1 THE PELVIS VASCULAR AND NERVOUS SYSTEM SOMATIC AND AUTONOMIC NERVES

2 THE ABDOMINAL AORTA The abdominal aorta begins at the aor9c hiatus in the diaphragm at the level of the T12 vertebra and ends at the level of the L4 vertebra by dividing into the right and lee common iliac arteries. The abdominal aorta is approximately 13 cm in length.

3 The branches of the aorta are described as: anterior, lateral and dorsal. The anterior and lateral branches are distributed to the viscera. The dorsal branches supply the body wall, vertebral column, vertebral canal and its contents. THE ABDOMINAL AORTA The branches of the aorta: inferior phrenic a. celiac trunk superior mesenteric a. middle suprarenal a. renal a. teshcular or ovarian a. four lumbar aa. inferior mesenteric a. median sacral a. common iliac a.

4 THE ABDOMINAL AORTA THE BRANCHES OF THE AORTA INFERIOR PHRENIC A. Paired arteries that supply the diaphragm, which they enter from below. It supplies diaphragm and gives superior suprarenal arteries. CELIAC TRUNK Common stem of the lek gastric, common hepahc and splenic arteries at the level of T12. Anterior to the celiac trunk lies the omental bursa. The celiac plexus surrounds the trunk, sending extensions along its branches. The body of the pancreas and the splenic vein are inferior to the celiac trunk. Branches: splenic artery common hepahc artery lek gastric

5 THE ABDOMINAL AORTA THE BRANCHES OF THE AORTA CELIAC TRUNK - SPLENIC ARTERY This is the largest branch of the coeliac axis and its course is among the most tortuous in the body. It lies: posterior to the omental bursa, anterior to the lek kidney, along the superior border of the pancreas. The splenic artery gives off various branches to the pancreas in its course and gives off short gastric arteries to the stomach just prior to dividing or from its terminal branches.

6 THE BRANCHES OF THE AORTA CELIAC TRUNK - HEPATIC ARTERY AKer its origin from the coeliac axis, the hepahc artery passes anteriorly and laterally below the epiploic foramen to the upper aspect of the first part of the duodenum. THE ABDOMINAL AORTA It may be subdivided into the common hepa9c artery, from the coeliac trunk to the origin of the gastroduodenal artery, and the hepa9c artery proper from the origin of the gastroduodenal artery to its bifurcahon.

7 THE ABDOMINAL AORTA THE BRANCHES OF THE AORTA CELIAC TRUNK - LEFT GASTRIC ARTERY The lek gastric artery is the smallest branch of the coeliac axis. It runs along the lesser curvature between the two peritoneal leaves of the lesser omentum. SUPERIOR MESENTERIC ARTERY Unpaired branch of the aorta arising about 1 cm below the celiac trunk. It extends from behind the pancreas to the uncinate process and passes with its branches into the mesentery and mesocolon.

8 THE ABDOMINAL AORTA THE BRANCHES OF THE AORTA MIDDLE SUPRARENAL ARTERY Arises from the lateral aspect of the abdominal aorta, level with the superior mesenteric artery and supplies the suprarenal gland. RENAL ARTERY The largest branches of the abdominal aorta, it arises from the aorta in front of L1 and divides into several branches which enter the kidney. The right is longer and usually arises slightly higher than the lek. It passes posterior to: the inferior vena cava, right renal vein, head of the pancreas and second part of the duodenum. The lek renal artery arises a lirle lower down and passes behind the lek renal vein, the body of the pancreas and the splenic vein.

9 THE BRANCHES OF THE AORTA TESTICULAR OR OVARIAN ARTERY The gonadal arteries are two long vessels, that arise from the aorta inferior to the renal arteries. Each passes inferolaterally under the parietal peritoneum on psoas major. Anterior to psoas major it crosses in front of the ureter. THE ABDOMINAL AORTA FOUR LUMBAR ARTERIES They arise from the posterolateral aspect of the aorta, which correspond to the intercostal arteries. INFERIOR MESENTERIC ARTERY It arises from the anterior or lek anterolateral aspect of the aorta. The inferior mesenteric artery is usually smaller in calibre than the superior mesenteric artery.

10 THE ABDOMINAL AORTA THE BRANCHES OF THE AORTA MEDIAN SACRAL ARTERY Arises from the posterior aspect of the aorta a lirle above its bifurcahon. It descends in the midline and ends in the coccygeal body. COMMON ILIAC ARTERY It extends from the bifurcahon of the descending aorta at L4 to its division into the internal and external iliac arteries in front of the sacroiliac joint. The common iliac arteries diverge and run inferolaterally, following the medial border of the psoas muscles to the pelvic brim. The internal iliac artery enters the pelvis. The external iliac artery follows the iliopsoas muscle, gives rise to the inferior epigastric and deep circumflex iliac arteries

11 RELATIONS OF ABDOMINAL AORTA: Celiac plexus and ganglion Body of the pancreas and splenic vein LeK renal vein Horizontal part of the duodenum Coils of small inteshne THE ABDOMINAL AORTA RELATIONS OF ABDOMINAL AORTA: On the right, the aorta is related to the azygos vein, cisterna chyi, thoracic duct, right crus of the diaphragm, and right celiac ganglion. RELATIONS OF ABDOMINAL AORTA: On the lee, the aorta is related to the lek crus of the diaphragm and the lek celiac ganglion.

12 ARTERIES OF THE PELVIS VEINS OF THE PELVIS LYMPHATIC DRAINAGE OF THE PELVIS INNERVATION OF THE PELVIS

13 6 main arteries enter the lesser pelvis of females: the paired internal iliac and ovarian arteries the unpaired median sacral the superior rectal arteries. ARTERIES Since the teshcular arteries DO NOT enter the lesser pelvis, only 4 main arteries enter the lesser pelvis of males: the paired internal iliac the unpaired median sacral the superior rectal arteries.

14 The common and external iliac vessels and the lymphahcs which drain the lower limb lie along the pelvic brim. ARTERIES The true pelvis contains the internal iliac arteries and veins and the lymphahcs which drain the majority of the pelvic viscera. The abdominal aorta bifurcates into the right and lek common iliac arteries anterolateral to the lee side of the L4 vertebral body. These arteries diverge as they descend and divide at the level of the sacroiliac joint into external and internal iliac arteries at the level of the IV disc between the L5 and S1 vertebrae

15 The external iliac artery is the principal artery of the lower limb. ARTERIES The internal iliac artery provides the principal supply to the walls and viscera of the pelvis, the perineum and the gluteal region.

16 THE RIGHT COMMON ILIAC ARTERY It is covered by the parietal peritoneum, which separates it from the coils of the small inteshne. The right common iliac artery passes obliquely across part of the L4 and L5 vertebral bodies. ARTERIES The right common iliac artery is crossed anteriorly by the sympathehc rami to the pelvic plexus and, at its division into internal and external iliac arteries, by the ureter. Posteriorly, the right common iliac artery is separated from the fourth and fikh lumbar vertebral bodies by the right sympathehc trunk, the terminal parts of the common iliac veins and the start of the inferior vena cava, the obturator nerve, lumbosacral trunk and iliolumbar artery. Laterally, the inferior vena cava and the right common iliac vein lie superiorly and the right psoas major lies inferiorly.

17 THE LEFT COMMON ILIAC ARTERY The lee common iliac artery is shorter than the right. ARTERIES Lying anterior to the lek common iliac artery are: the sympathehc rami to the pelvic plexus, the superior rectal artery the ureter. Posterior to the lek iliac artery are: the sympathehc trunk, the L4 & L5 vertebral bodies the obturator nerve, lumbosacral trunk, iliolumbar artery.

18 The external iliac arteries are of larger calibre than the internal iliac arteries. ARTERIES The external iliac artery descends laterally along the medial border of psoas major, from the common iliac bifurcahon to a point midway between the ASIS and the symphysis pubis. The external iliac artery enters the thigh posterior to the inguinal ligament to become the femoral artery. In addihon to the external iliac and internal iliac branches, each common iliac artery also gives small branches to the peritoneum, psoas major, ureter.

19 THE INTERNAL ILIAC ARTERY The internal iliac artery begins at the common iliac bifurcahon, level with the lumbosacral intervertebral disc and anterior to the sacroiliac joint. It descends posteriorly to the superior margin of the greater sciahc foramen. Anterior to the artery are: ureter, in females, the ovary and fimbriated end of the uterine tube. Posterior to the artery are: internal iliac vein, lumbosacral trunk, sacroiliac joint. ARTERIES

20 THE INTERNAL ILIAC ARTERY ARTERIES Lateral are: external iliac vein, between the artery and psoas major, obturator nerve lying inferior to the vein. At the superior margin of the greater sciahc foramen divides into: anterior trunk, which conhnues in the same line towards the ischial spine, and posterior trunk, which passes back to the greater sciahc foramen.

21 THE ANTERIOR TRUNK BRANCHES OF THE INTERNAL ILIAC ARTERY The branches of the anterior trunk of the internal iliac artery are: superior vesical, inferior vesical, middle rectal, vaginal, obturator, uterine, internal pudendal inferior gluteal. ARTERIES

22 THE ANTERIOR TRUNK BRANCHES OF THE INTERNAL ILIAC ARTERY The superior vesical artery is the first large branch of the anterior trunk. It lies on the lateral wall of the pelvis just below the brim and runs anteroinferiorly. The superior vesical artery supplies the distal end of the ureter, the bladder, the proximal end of the vas deferens and the seminal vesicles. ARTERIES The inferior vesical artery supplies the bladder, the prostate, the seminal vesicles and the vas deferens. The middle rectal artery may arise independently from the internal iliac artery. The middle rectal artery runs into the lateral fascial coverings of the mesorectum.

23 THE ANTERIOR TRUNK BRANCHES OF THE INTERNAL ILIAC ARTERY The vaginal artery is the homolog to the inferior vesical artery in males. ARTERIES The obturator artery runs anteroinferiorly on the lateral pelvic wall to the upper part of the obturator foramen. In the pelvis, the obturator artery is related laterally to the fascia over obturator internus and is crossed on its medial aspect by the ureter and, in the male, by the vas deferens. The obturator nerve is above the artery, the obturator vein below it. The obturator artery supplies: pelvic muscles, nutrient artery to ilium, head of femur, muscles of medial compartment of thigh.

24 THE ANTERIOR TRUNK BRANCHES OF THE INTERNAL ILIAC ARTERY ARTERIES The uterine artery is an addihonal branch in females. Developmentally, it is the homolog of the artery to the ductus deferens in the male. The uterine artery passes directly superior to the ureter. The uterine artery descends on the lateral wall of the pelvis, anterior to the internal iliac artery, and passes medially in base of broad ligament to reach the junchon of the uterus and vagina. The internal pudendal artery arises just below the origin of the obturator artery. The internal pudendal artery descends laterally to the inferior rim of the greater sciahc foramen, where it leaves the pelvis between piriformis and ischiococcygeus to enter the gluteal region.

25 THE ANTERIOR TRUNK BRANCHES OF THE INTERNAL ILIAC ARTERY ARTERIES The internal pudendal artery curves around the dorsum of the ischial spine to enter the perineum by the lesser sciahc foramen. The internal pudendal artery supplies muscles and skin of anal and urogenital triangles, erechle bodies. The inferior gluteal artery is the larger terminal branch of the anterior internal iliac trunk and principally supplies the burock and thigh. The inferior gluteal artery descends posteriorly, anterior to the sacral plexus and piriformis but posterior to the internal pudendal artery. The inferior gluteal artery leaves the pelvis through the inferior part of the greater sciahc foramen, inferior to the piriformis muscle. The inferior gluteal artery supplies the muscles and skin of the burock, and the posterior surface of the thigh.

26 THE ANTERIOR TRUNK BRANCHES OF THE INTERNAL ILIAC ARTERY Before birth, the umbilical arteries are the main conhnuahon of the internal iliac arteries. ARTERIES Before birth, the umbilical arteries are passing along the lateral pelvic wall and then ascending the anterior abdominal wall to and through the umbilical ring into the umbilical cord. The occluded parts form fibrous cords called the medial umbilical ligaments.

27 THE POSTERIOR TRUNK BRANCHES OF THE INTERNAL ILIAC ARTERY The branches of the posterior trunk of the internal iliac artery are: iliolumbar, lateral sacral, superior gluteal arteries. ARTERIES The iliolumbar artery is the first branch of the posterior trunk and ascends laterally anterior to the sacroiliac joint and lumbosacral nerve trunk.

28 THE POSTERIOR TRUNK BRANCHES OF THE INTERNAL ILIAC ARTERY The iliolumbar artery supplies: psoas major and quadratus lumborum gluteal and abdominal muscles iliacus cauda equina ARTERIES The lateral sacral arteries are usually double, or if single, divide rapidly into superior and inferior branches. The lateral sacral arteries supply the psoas major and quadratus lumborum muscles. The superior gluteal artery is the largest branch of the internal iliac artery.

29 THE POSTERIOR TRUNK BRANCHES OF THE INTERNAL ILIAC ARTERY The superior gluteal artery is leaving the pelvis by the greater sciahc foramen above piriformis and dividing into superficial and deep branches. ARTERIES The superior gluteal artery supplies piriformis, obturator internus and a nutrient artery to the ilium.

30 THE OVARIAN ARTERY The ovarian artery arises from the abdominal aorta inferior to the renal artery but considerably superior to the inferior mesenteric artery. The ovarian artery runs anterior to the ureter on the posterior abdominal wall, usually giving branches to it. The ovarian artery descends behind the peritoneum, and at the brim of the pelvis crosses with the ureter over the external iliac artery and vein to enter the true pelvic cavity. ARTERIES In the true pelvic cavity, the ovarian artery turns medially in the ovarian suspensory ligament and splits into a branch to the mesovarium that supplies the ovary, and a branch that conhnues into the uterine broad ligament, below the uterine tube, and supplies the tube.

31 THE MEDIAN SACRAL ARTERY ARTERIES The median sacral artery is a small unpaired artery that usually arises from the posterior surface of the abdominal aorta, just superior to its bifurcahon, but it may arise from its anterior surface. THE SUPERIOR RECTAL ARTERY The superior rectal artery is the direct conhnuahon of the inferior mesenteric artery.

32 The true pelvis contains a large number of veins which drain the pelvic walls and most of the viscera contained within the pelvis, and which carry venous blood from the gluteal region, hip and thigh. Pelvic venous plexuses are formed by the interjoining veins surrounding the pelvic viscera. The various plexuses within the lesser pelvis (rectal, vesical, prostahc, uterine, and vaginal) unite and are drained mainly by tributaries of the internal iliac veins. Some of them drain through the superior rectal vein into the IMV, or through lateral sacral veins into the internal vertebral venous plexus. AddiHonal relahvely minor paths of venous drainage from the lesser pelvis include the parietal median sacral vein and, in females, the ovarian veins. VEINS

33 THE COMMON ILIAC VEINS The common iliac vein is formed by the union of the external and internal iliac veins, anterior to the sacroiliac joints. VEINS The right common iliac vein is shorter and more nearly verhcal, lying posterior and then lateral to its artery. The right common iliac vein ascends obliquely to end at the right side of the L5 vertebra, unihng with the contralateral vessel to form the IVC.

34 THE INTERNAL ILIAC VEINS The internal iliac veins form superior to the greater sciahc foramen and lie postero-inferior to the internal iliac arteries VEINS The tributaries of the internal iliac veins are: gluteal, internal pudendal obturator veins, lateral sacral veins, middle rectal, vesical, uterine, vaginal veins

35 The lymph nodes in the pelvis are grouped around the common, external and internal iliac vessels. Four primary groups of nodes are: external iliac lymph nodes: lie above the pelvic brim, along the external iliac vessels. They receive lymph mainly from the inguinal lymph nodes. internal iliac lymph nodes: clustered around the anterior and posterior divisions of the internal iliac artery. They receive drainage from the inferior pelvic viscera, deep perineum, and gluteal region and drain into the common iliac nodes. sacral lymph nodes: lie in the concavity of the sacrum. They receive lymph from postero-inferior pelvic viscera. common iliac lymph nodes: lie superior to the pelvic brim, along the common iliac blood vessels. These lymph nodes receive drain age from the three main groups listed above. These nodes begin a common route for drainage from the pelvis that passes next to the lumbar nodes. LYMPH

36 The pelvis contains the lumbosacral nerve trunk, the sacral and coccygeal plexuses and the pelvic parts of the sympathehc and parasympathehc systems. NERVES The ventral rami of the sacral and coccygeal spinal nerves form the sacral and coccygeal plexuses The sacral plexus is formed by the lumbosacral trunk, the S1-S3 ventral rami and part of the S4 ventral ramus. The lumbar part of the lumbosacral trunk contains part of the L4 and the L5 ventral rami. The lumbar part of the lumbosacral trunk it appears at the medial margin of psoas major, and descends over the pelvic brim anterior to the sacroiliac joint to join the S1 ramus.

37 THE SACRAL PLEXUS NERVES The sacral plexus lies against the posterior pelvic wall anterior to piriformis, posterior to the internal iliac vessels and ureter, and behind the sigmoid colon on the lek. The superior gluteal vessels run either between the lumbosacral trunk and first sacral ventral ramus or between the first and second sacral rami. Most branches of the sacral plexus leave the pelvis through the greater sciahc foramen. The two main nerves arising from the sacral plexus, the sciahc and pudendal nerves, lie external to the parietal pelvic fascia. The scia9c nerve is the largest nerve in the body. It is formed as the large anterior rami of spinal nerves L4 S3 converge on the anterior surface of the piriformis.

38 THE SACRAL PLEXUS NERVES The scia9c nerve descends between the greater trochanter and ischial tuberosity, along the back of the thigh, dividing into the Hbial and common fibular nerves at a varying level proximal to the knee. The pudendal nerve arises from the ventral divisions of the S2, S3 and S4 ventral rami and is formed just above the superior border of the sacrotuberous ligament and the upper fibres of ischiococcygeus. The pudendal nerve is the main nerve of the perineum and the chief sensory nerve of the external genitalia. Accompanied by the internal pudendal artery, it leaves the pelvis through the greater sciahc foramen between the piriformis and coccygeus muscles.

39 THE SACRAL PLEXUS The pudendal nerve hooks around the ischial spine and sacrospinous ligament. The pudendal nerve accompanies the internal pudendal artery through the lesser sciahc foramen into the pudendal (Alcock s) canal on the lateral wall of the ischio-anal fossa. The pudendal nerve gives rise to the inferior rectal nerve, the perineal nerve and the dorsal nerve of the penis or clitoris. NERVES The superior gluteal nerve leaves the pelvis through the greater sciahc foramen, superior to the piriformis to supply muscles in the gluteal region. The inferior gluteal nerve leaves the pelvis through the greater sciahc foramen, inferior to the piriformis and superficial to the sciahc nerve, accompanying the inferior gluteal artery.

40 THE COCCYGEAL PLEXUS The coccygeal plexus is a small network of nerve fibers formed by the anterior rami of S4 and S5 and the coccygeal nerves. NERVES The coccygeal plexus lies on the pelvic surface of the coccygeus and supplies this muscle, part of the levator ani, and the sacrococcygeal joint.

41 THE PELVIC AUTONOMIC NERVES The autonomic supply to the abdominal and pelvic viscera is via: the abdominopelvic part of the sympathehc chain and the greater, lesser and least splanchnic nerves (sympathehc), and the vagus and pelvic parasympathehc nerves (parasympathehc). NERVES Autonomic nerves enter the pelvic cavity via four routes: sacral sympathe9c trunks: primarily provide sympathehc innervahon to the lower limbs. peri-arterial plexuses: postsynaphc, sympathehc, vasomotor fibers to superior rectal, ovarian, and internal iliac arteries and their derivahve branches. hypogastric plexuses: most important route by which sympathehc fibers are conveyed to the pelvic viscera. pelvic splanchnic nerves: pathway for parasympathehc innervahon of pelvic viscera and descending and sigmoid colon.

42 THE SYMPATHETIC INNERVATION NERVES The cell bodies of neurones of the sympathehc supply of the abdomen and pelvis lie in the intermediolateral grey marer of the T1 to T12 and first two lumbar (L1-L2) spinal segments. These neurones give rise to myelinated axons which travel in the ventral ramus of the spinal nerve of the same level, leaving it via the white ramus communicans to enter a thoracic or lumbar paravertebral ganglion. These give rise to the: greater, lesser, least splanchnic nerves, lumbar, sacral splanchnic nerves.

43 THE PELVIC AUTONOMIC NERVES The sacral sympathe9c trunks are the inferior conhnuahon of the lumbar sympathehc trunks. NERVES The sacral sympathe9c trunks descend posterior to the rectum in the extraperitoneal connechve Hssue and send communicahng branches (gray rami communicantes) to each of the anterior rami of the sacral and coccygeal nerves.

44 THE PELVIC AUTONOMIC NERVES NERVES The primary funchon of the sacral sympathehc trunks is to provide postsynaphc fibers to the sacral plexus for sympathehc innervahon of the lower limb. The peri-arterial plexuses of the ovarian, superior rectal, and internal iliac arteries are minor routes by which sympathehc fibers enter the pelvis. The hypogastric plexuses (superior and inferior) are networks of sympathehc and visceral afferent nerve fibers. The main part of the superior hypogastric plexus is a prolongahon of the intermesenteric plexus, which lies inferior to the bifurcahon of the aorta. The superior hypogastric plexus enters the pelvis, dividing into right and lek hypogastric nerves, which descend on the anterior surface of the sacrum.

45 THE PELVIC AUTONOMIC NERVES These nerves descend lateral to the rectum and then spread in a fan-like fashion as they merge with the pelvic splanchnic nerves to form the right and lek inferior hypogastric plexuses. NERVES The inferior hypogastric plexuses thus contain both sympathehc and parasympathehc fibers as well as visceral afferent fibers. Pelvic splanchnic nerves arise in the pelvis from the anterior rami of spinal nerves S2 S4 of the sacral plexus The pelvic splanchic nerves convey presynaphc parasympathehc fibers derived from the S2 S4 spinal cord segments and visceral afferent fibers from cell bodies in the spinal ganglia of the corresponding spinal nerves.

46 THE PELVIC AUTONOMIC NERVES The hypogastric/pelvic system of plexuses, receiving sympathehc fibers via lumbar splanchnic nerves and parasympathehc fibers via pelvic splanchnic nerves, innervate the pelvic viscera. NERVES