Omran Saeed. Mohammad Al-muhtaseb. 1 P a g e

13 Omran Saeed Mohammad Al-muhtaseb 1 P a g e

Posterior abdominal wall - The diaphragm separates between thoracic cavity and abdominal cavity. Structures of posterior abdominal wall: (below diaphragm) Psoas major Muscles Psoas minor* (if present) Quadratus lumborum Iliacus - Aponeurosis of transversus abdominis muscle. - The five-lumber vertebra and their intervertebral discs. - Iliac crest, iliac fossa. - The last rib (12 th rib). Psoas major Iliacus Quadratus lumborum Origin Bodies, transverse prosses of lumbar vertebra and inter vertebral discs Iliac fossa Iliolumbar ligament** And iliac crest insertion Lesser trochanter of femur Lesser trochanter of femur Last rib action Flexion of the thigh and vertebral column Lateral flexion of hip & thigh Fixation of the last rib or stretch the rib downward Nerve supply T12 L1 L2 L3 Femoral nerve T12 L1 L2 L3 * There are many muscles which are not present in all population such as palmaris longus in the upper limb and pyramidalis muscle. ** It is located between iliac crest and 5 th lumbar vertebrae 2 P a g e

- Arcuate ligament (medial, median and lateral), which is part of the origin of diaphragm, arches above psoas and quadratus muscles. Median is in the middle above abdominal aorta Medial above psoas major. Lateral above quadratus lumborum. Refer to diaphragm slide in the MSS system for illustration. Look at slide number 7 in our lecture. The doctor mentioned latissimus dorsi muscle, lumbar fascia, digitation of external oblique muscle, Lateral cutaneous nerve and subcostal nerves which come from the chest. Structures in the posterior abdominal wall We will focus on abdominal aorta and inferior vena cava. Abdominal aorta starts as ascending aorta emerge from left ventricle of the heart and give us the right and left coronary arteries of the heart. Then it becomes the arch of the aorta. After that it continues as descending thoracic then abdominal aorta which ends in the right and left common iliac arteries. Common iliac branches to external and internal iliac. The external drains to the lower limb while the internal drains to the pelvic viscera (More details later on). -Now let s talk about abdominal aorta. It starts with an orifice in the diaphragm called aortic orifice (at the level of T12 midline). What are the structures pass through this orifice? Azygous vein. cisterna chyli (lymphatic sac) at the right side of abdominal aorta. Abdominal aorta ends at L4 lumbar vertebra and it is deviated to left side. 3 P a g e

Relations of abdominal aorta: Anterior: Pancreas. Horizontal part (3 rd Coils of small intestines. part) of duodenum. Crossed anteriorly by left renal vein (left renal vein drains to inferior vena cava which is at the right side of abdominal aorta that s why it crosses abdominal aorta). Right: Inferior vena cava. Cisterna chyli. Beginning of azygous vein. Left: Sympathetic chain behind the edge of abdominal aorta. *You can refer to the mind map in the last slide for more illustration. Branches of abdominal aorta Single branches: (3 front & I back) anterior surface 1- celiac trunk: -very short (about 1 cm). origin: upper border of L1. Some books assume that the origin is from the lower border of T12. Branches: - left gastric: Supplies the stomach and the lower third of esophagus. - splenic: Tortuous, goes along the upper border of pancreas and gives pancreatic arteries and ends in the hilum of spleen and gives 5 or 6 4 P a g e

branches. Also, it gives short gastric for the fundus of stomach 5 to 7 branches (present in gastrosplenic ligament). - hepatic: drains to the liver and pass through the free edge of lesser omentum. It gives us gastroduodenal artery which travels behind the first part of duodenum. (gastroduodenal gives superior pancreaticoduodenal and right gastroepiploic arteries). It ends with right (gives cystic artery) and left hepatic arteries. 2- superior mesenteric artery: Gives inferior pancreaticoduodenal, Right colic, middle colic and ileocolic (the end of superior mesenteric gives anterior and posterior cecal and the posterior gives appendicular then gives jejunal and iliac branches as we said about them they are at the root of mesentery and they make arcades and vasa recta. In the ilium it s complicated and short vasa recta). 3- interior mesenteric artery: Origin: at the level of L3. Horizontal part of duodenum is anterior to it (origin of the artery). Branches: -Left colic drains in the lateral third of transverse and descending colon. -Sigmoidal arteries drain in the sigmoid. At the end of inferior mesenteric > superior rectal artery goes to the rectal and upper half of anal canal. *** * Remember that celiac supplies the foregut, superior mesenteric supplies midgut and inferior mesenteric supplies hindgut posterior surface: Median sacral artery. Some books consider that it is a continuation of abdominal aorta. 5 P a g e

Marginal artery anastomosis between colic arteries (arteries of ascending, transverse, descending and sigmoid colon). So, there is an anastomosis between these arteries. It is located at the medial side of the colon and internal. (it makes connection and wraps around the colon). As we said the abdominal aorta branches to common iliac arteries (right and left) then the common iliac gives internal and external iliac arteries. The bifurcation of the common iliac artery on each side is crossed anteriorly by the ureter. external iliac artery: supplies the lower limb Branches: -Inferior epigastric artery. It Enters the rectus sheath and meets the superior epigastric. -Deep Circumflex iliac artery which goes to the anterior superior iliac spine. Internal iliac artery: supplies the pelvic viscera and lateral wall of the pelvis (more details in urogenital system) Branches: 1- Posterior division: goes parietal to the wall of pelvis a- Iliolumbar artery ascends at the ala of the sacra and goes to the lumber vertebra. b- Lateral sacral arteries go to the sacrum and enter the foramina of sacra. They start as two arteries then they become four (each branch gives two branches). c- Superior gluteal artery passes through the greater sciatic foramen above piriformis. 2- Anterior division: a- Obturator artery (occasionally from inferior epigastric artery) - crosses obturator foramen and the pelvis. b- Inferior gluteal artery passes through greater sciatic foramen below piriformis muscle. 6 P a g e

c- Umbilical artery directed to the umbilicus and it gets obliterated after delivery (obliteration for the distal part [becomes lateral umbilical ligament]). The proximal part gives superior vesical artery for the urinary bladder (superiorly to the bladder). d- Uterine artery (females). It is tortious for the uterus or deferential artery (males) e- Vaginal artery (females, can also arise from uterine artery) supply vagina f- inferior vesical artery - urinary bladder (in males) g- Middle rectal artery rectum h- Internal pudendal artery. The last two are at the end of internal iliac artery. We must memorize the names only (branches of internal iliac) In this system. Paired branches: Paired arteries divided into right and left while single arteries are not. Paired branches: 1 front, 4back & 3 side 1-1 front ---- testicular or ovarian artery at level L2 2-4 back ---- lumbar arteries 3-3 side of aorta - Inferior phrenic. A - Middle suprarenal. A - Renal. A (at the level of L2 drain in kidney) *Suprarenal gland is rich in blood supply (3 arteries) Superior Suprarenal: from phrenic artery Middle Suprarenal: from abdominal aorta Inferior Suprarenal: from Renal A. 7 P a g e

8 P a g e Veins of the posterior abdominal wall The most important vein in the posterior abdominal wall is inferior vena cava. inferior vena cava. It is lateral to the abdominal aorta (at the right side). It starts at the level of L5 on the right side. It came from right and left common iliac veins and common iliac came from external and internal iliac (opposite to the arteries). It ends at inferior vena caval orifice (orifice in the diaphragm) at the level of T8 in the right cupula of diaphragm and then directly drains to the right atrium. Azygous vein drain to the arch of azygous then superior vena cava and finally to the right atrium. As you know right atrium Receives deoxygenated blood from all the body by three veins which are: superior vena cave, inferior vena cava and coronary sinus from the heart. The Tributaries of inferior vena cava: (opposite to the branches of the artery) -Renal vein. -Testicular or ovarian vein from testis or ovaries. -Lumbar veins (4 veins). -Azygous vein from the posterior wall of abdomen. -Suprarenal vein: Right: drain directly to inferior vena cava. Left: goes to left renal vein then to inferior vena cava. -Phrenic veins from diaphragm. -Hepatic veins from the liver (three). We notice that single arteries are opposite to single veins. They drain to the portal vein then to the liver.

Portal vein 5 cm long (2 inches). Formed behind the neck of pancreas. Goes to the liver then branches to right portal (cystic vein drains in it) and left portal. Tributaries: Superior mesenteric. Splenic Inferior mesenteric (drains either in splenic of in the junction) Gastric veins (Rt. & L). Cystic vein. From that we conclude that there is portal circulation (portal vein to the liver) and systemic circulation (inferior vena cave to the heart). Pay attention to ductus venosus which is closes after delivery and converts to ligamentum. Also notice umbilical vein which make ligamentum teres. Relations of inferior vena cava: Anterior: coils of small intestine esp. the ileum. First and third part of duodenum. (I.V.C and portal vein are posterior to the first part of duodenum). Head of pancreas. Common bile duct. Related to foramen of Winslow Portal vein - lies in deep groove of liver Tributaries of I.V.C: (from slides) Two anterior visceral tributaries: the hepatic veins Three lateral visceral tributaries: the right suprarenal vein (the left vein drains into the left renal vein), renal veins, and right testicular or ovarian vein (the left vein drains into the left renal vein) 9 P a g e

Five lateral abdominal wall tributaries: the inferior phrenic vein and four lumbar veins. Three veins of origin: two common iliac veins and the median sacral vein. Portal systemic anastomosis: portal means portal vein. Systemic means going to inferior vena cava then to the heart. Is there connection between portal and systemic circulation? No, there isn t connection in normal people Lower third of esophagus have systemic and portal drainage. Systemic like azygous vein takes blood to superior vena cava while portal which is left gastric vein goes to the portal. This site called portal systemic anastomosis. The problem with this is when there is liver cirrhosis or fibrosis as a result the blood supply of hepatocyte is stopped. Then obstruction inside the liver takes place and that means that blood in portal vein can t pass and accordingly the blood goes back to its source. For example, the blood in the left gastric vein goes back to the wall of the esophagus in the lower third instead of portal vein. Then the blood converges in the lower third where it meets the azygous vein so the anastomosis between portal and systemic occurs. The latter connection is due to portal hypertension and the veins become dilated tortuous and engorged with blood and that may result in bleeding, so the patient is vomiting blood this state called haematemesis. In the past many people were dying from esophageal varices, but nowadays it can be treated easily by entering coagulative materials or ice by endoscope. 10 P a g e

Portal systemic anastomosis Region Esophageal (lower third) Rectal Paraumbilical Retroperitoneal Intrahepatic Name of clinical condition Esophageal varices Hemorrhoids (fresh blood present in stool) Caput medusae (dilated and tortuous veins around umbilicus and make radial distribution*) (no clinical name) Patent ductus venosus Portal circulation Esophageal branch of left gastric vein Superior rectal vein (drains to inferior Mesenteric then portal vein) Paraumbilical veins Right colic vein, middle colic vein, left colic vein Left branch of portal vein Systemic circulation Esophageal branches of Azygos vein Middle rectal veins and inferior rectal veins (drains to I.V.C) Superficial epigastric veins Renal vein, suprarenal vein, paravertebral vein, and gonadal vein Inferior vena cava Bare area of liver Also makes connection between systemic and portal circulation. Read the table carefully. The main reason of anastomosis is liver cirrhosis and fibrosis by bilharzial infection, congenital by ductus venosus (stay opened) or heart disease. *Radial distribution here means lines destined toward the umbilicus. Lymphatics on the Posterior Abdominal Wall Notice that lymph nodes in the GI track around blood vessels. The lower limbs usually drain to inguinal lymph nodes (superficial and deep). Around external iliac artery there is external iliac lymph nodes. More abundant is present around internal iliac all pelvic viscera converge in internal iliac lymph nodes. 11 P a g e

In general, there are two types of lymphatic in lymph nodes; afferent and efferent. In our case the efferent lymph nodes reach cisterna chyli. Preaortic lymph nodes: Celiac, superior mesenteric and inferior mesenteric lymph nodes around the origin of the arteries. In other words, the organs from the lower third of esophagus until upper half of anal canal drain to preaortic L.N. After celiac L.N. we have efferent goes through intestinal trunk to cisterna chyli. Para-aortic (lumbar) lymph nodes: They receive lymphatics from kidneys, suprarenal, testis in male, ovaries and uterus in females. The efferent lymph vessels converge around common iliac and form the right and left lumbar trunk then finally drain to cisterna chyli. There are two important trunks around aorta which are intestinal trunk (at the two sides of aorta) and lumbar trunk. They end at cisterna chyli. WHERE IS CISTERNA CHYLI? This sac located in the midline on the right side of abdominal aorta. Thoracic duct which is forty-five cm long arises from it. Thoracic duct is beaded since it contains valves. Thoracic duct ends at the beginning of left brachiocephalic vein (the union internal jugular and subclavian veins). The duct is located at the junction at the root of the neck. Sorry for any mistakes Don t forget to refer to slides If you wait for opportunities to occur, you will be one of the crowd (Edward De Bono) 12 P a g e

13 P a g e