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NOTES FROM THE APP3 SLIDES THAT COULDN’T BE UPLOADED SLIDE 4 (SAD PUCKER) You know that an organ which is (nearly completely) surrounded by peritoneum is called: an intraperitoneal organ, were going to focus on the retroperitoneal structures SPLEEN IS NOT RETROPERITONEAL SLIDE 5 THIS IS EXTRA INFORMATION Primary retroperitoneal structures are behind the peritoneum Can see that 2ndary retroperitoneal start with mesentery, but during embryological development, their mesentery adhere to the posterior abdominal wall causing them to become secondary retroperitoneal - These organs have less mobility The main ones you need to know are AD colon, duodenum (2 & 3 part), and most of pancreas (not tail) SLIDE 6 INTRAPERITONEAL A firm fist-sized organ with a notched superior border. The spleen develops in the proximal part of the dorsal foregut mesentery, dividing it into 2 ligaments à greater curvature of the stomach to the spleen – the gastro-splenic ligament + a part between spleen and the posterior abdominal wall, the lienorenal ligament (or splenorenal ligament). Diaphragmatic, colic, renal and gastric surfaces Processes red cells + source of B lymphocytes SLIDE 7 Diaphragmatic, colic, renal and gastric surfaces Between stomach and diaphragm Hidden by the 9,10,11 ribs posteriorly The left gastroepiploic and short gastric arteries are contained within the gastrosplenic ligament The splenic artery and vein, + the tip of the tail of the pancreas are contained within the lienorenal ligament Gastrosplenic is part of greater omentum SLIDE 8 Main artery of the foregut is coeliac trunk branches off into 3 arteries à left gastric, common hepatic and splenic… then there's more branching Focusing on the splenic artery… it gives off branches to both stomach (short gastric) which supply the fundus of the stomach and [other] vessels to the pancreas which you don’t need to know their names The splenic artery is above the splenic vein and they both run posteriorly along the superior surface of the pancreas The main thing you need to know about the vein (more info in the later slides) is that it joins with the inferior mesenteric artery then to the superior mesenteric artery to form the portal vein J The coeliac artery arises at T12-L1 and the superior mesenteric artery about 1 cm below itSLIDE 9 Short gastric arteries are distal branches of the splenic artery SLIDE 10 HAP is a branch of common hepatic artery which is a branch of coeliac trunk 8 is spleen SLIDE 13 (Blood supply of pancreas) The junction of the foregut and mid-gut is in the second part of the duodenum so… this part of the duodenum and the associated pancreas are supplied by both the CA & SMA Note that the pancreas passes anterior to the inferior vena cava, the abdominal aorta and the left kidney. The coeliac artery arises at T12-L1 and the superior mesenteric artery about 1 cm below it The superior mesenteric artery emerges between the head and uncinate process of the pancreas. Its branch to the duodenum and pancreas is the inferior pancreatico-duodenal artery. The coeliac artery à common hepatic à gastroduodenal artery à superior pancreatico duodenal artery Splenic artery also gives off some branches HPV and IVC behind head Splenic vein and artery near top of pancreas (vein lower) Aorta behind neck SLIDE 17 (Ascending + descending colon) SMA has branches to duodenum and pancreas. It also has branches to the mesentery and small intestine (jejunal and ileal arteries), to the junction of large and small intestines (ileocolic artery, including the small but important branch to the appendix), to the ascending colon (the right colic artery) and to the transverse colon (the middle colic artery). The hind-gut, from the distal third of the transverse colon to the rectum is supplied by the inferior mesenteric artery. Inferior mesenteric artery arises from the left anterior surface of the abdominal aorta considerably lower down the abdomen at L3 (the coeliac artery arises at T12-L1 and the superior mesenteric artery about 1 cm below it). It usually gives off a sharply ascending left colic artery to the descending colon whereas the main part continues inferiorly to become the sigmoid artery and the superior rectal artery The posterior abdominal wall and the paired organs associated with it i.e. the kidneys, adrenals and gonads are supplied by paired branches of the aorta. --------------- Relevant to small bowel------------------- The 1 part of the duodenum is intraperitoneal and is connected to the liver by the hepatoduodenal ligament (free edge of the lesser omentum) containing the hepatic artery, portal vein and common bile drdt thatthou saw in the previous session. Ligament of Treitz à The 3 and 4 part of the duodenum and the duodeno-jejunal flexure are suspended from the connective tissue around the coeliac trunk and the origin of the SMA by connective tissue and thin band of muscle.The arteries are jejunal or ileal branches of the SMA, which supply the midgut. The jejunal and ileal veins are tributaries of the superior mesenteric vein, which joins the portal vein draining into the liver. SLIDE 18 The superior mesenteric vein lies anterior and slightly to the right of the artery. It goes to the posterior surface of the pancreatic head where it joins the splenic vein to form the portal vein. The portal vein is posterior to the 1st part of the duodenum going to the region of the free edge of the lesser omentum, where it lies parallel to the hepatic artery. SLIDE 19 The lymph nodes are small, soft ovoid structures, whereas the ganglia are tough, fibrous structures interconnected by bundles of nerves giving branches that follow the arteries to the gut. Pre-aortic group of lymph nodes (coeliac, SM, IM) à drain midline structures which are likely sites of lymphatic spread of cancers from the gut and its glands. - Such as oesophagus, stomach, large intestine and pancreas à These are also common sites of primary cancer. - Another common route of spread of gut and pancreatic cancers is through the venous blood along the portal vein to the liver, where large secondary tumours may form. Para-aortic à drains lymph from bilateral structures - Such as kidneys, ureters, gonads Pre-aortic and para-aortic are retroperitoneal and they drain into the cisterna chyli (a sac at the end of the thoracic duct – follows vagus nerve through diaphragm) SLIDE 20 The coeliac and mesenteric sympathetic ganglia receive pre-ganglionic fibres from the splanchnic nerves (derived from the lower thoracic spinal nerves). After synapsing in the ganglia, the post-ganglionic fibres supply smooth muscle and glands in the gastro-intestinal tract. The sensory afferent fibres following the route of these efferent neurones are equally important, because they convey pain signals from the abdominal viscera. PELVIC SPLANCHNIC NERVES ARISE FROM S2,3,4 AND INNERVATE DISTAL 1/3 OF TRANSVERSE COLON ONWARDS Extra detail: Coeliac plexus à The plexus is formed in part by the greater and lesser splanchnic nerves of both sides, and fibers from the anterior and posterior vagal trunks. SMP à a continuation of the lower part of the coeliac plexus, receiving a branch from the junction of the right vagus nerve with the plexus. IMP à derived chiefly from the aortic plexus (+ pelvic splanchnic nerves from S2,3,4) Abdomen: vagus nerve (CN X), prevertebral ganglia, lower thoracic, pelvic and lumbar splanchnic nerves; they form plexuses: myenteric, coeliac, superior mesenteric, inferior mesenteric, superior hypogastric and inferior hypogastric plexuses. Pelvis: lumbosacral trunk (L4, L5), lumbar plexus (L1-L4), sacral plexus (L4-S4), coccygeal plexus (S4-Co), lumbar, sacral and pelvic splanchnic nervesSLIDE 25 (structure of kidneys) Fascia is a thin connective tissue that holds organs in place and can have other functions like sensation Reference: SLIDE 26 Cortex and medulla are renal parenchyma Medulla and papilla are continuous Multiple major calyx drain into renal pelvis Renal sinus contains à renal pelvis, renal calyces, blood vessels, nerves and fat Cortex (OUTSIDE) à medulla à papilla à Minor calyx à Major calyx à renal pelvis à ureter SLIDE 27 Sit around ribs 11 and 12 Right kidney is lower due to the liver: - Superiorly – adrenals - Superiorly and laterally – hepatic relations - Inferiorly – colic area - Medially – duodenal - Superiorly posteriorly – diaphragm - Posteriorly inferiorly from medial to lateral – psoas, quadratus lumborum, transversus abdominis (behind obliques) Left kidney: - Superiorly – adrenals, stomach, spleen - Anteriorly – pancreas - Inferiorly – small bowel (jejunum) - Laterally – colic SLIDE 28 Ureter goes over the iliac arteries and inserts at the back of the urinary bladder Blood supply is from arteries that passes by Gonadal arteries are high up due to embryological origin There are three locations where the ureter narrows: - Ureteropelvic junction à the junction between the renal pelvis and ureters in the kidney hilum - Pelvic Brim à where the iliac vessels cross over the ureter in the pelvis - Ureterovesical junction à vesico- means bladder, so it’s where the ureters enter the wall of the bladder Patients with kidney stones may present with writhing pain which radiates from the loin to groin. The gold-standard for diagnosing kidney stones is a CT-KUB (CT- Kidney/Ureter/Bladder). SLIDE 29 Lie in the same fat as kidneysIVC in front of right gland Left adrenal gland lies near left crus of diaphragm The adrenal glands receive huge numbers of pre-ganglionic fibres that synapse with the adrenaline-secreting chromaffin cells of the adrenal medulla, which are modified post- ganglionic sympathetic neurones. SLIDE 30 Extra content: The renal arteries then divide into the anterior and posterior branches on approach to the hilum to supply the renal parenchyma. The avascular plane of the kidney (line of Brodel) forms the ‘watershed region’ of the kidney. It is the region of the kidney which is supplied by both the anterior and posterior branches of the renal arteries and is therefore the route of surgical access to the kidneys due to minimal risk of damage to arterial supply and to the major arterial vasculature. Accessory renal arteries (additional renal arteries) are fairly common. They can originate either above or below the renal artery and may have hilar or non-hilar entry to the kidney. Accessory arteries which do not enter via the hilum are known as extra-hilar or aberrant arteries. SLIDE 31 - Identify the slender gonadal (testicular or ovarian) artery as it branches from the abdominal aorta just inferior to the renal artery. - Why do the gonads receive blood and nerve supply and lymphatic drainage from the upper abdomen? - Gonads embryologically start in the abdomen and make their way to their respective areas - Which of these three supplies is clinically most important? - It is between the blood and lymph supply as they are methods by which cancers can spread