Abdominal Aorta Branches - Anatomy PDF

XY2141. ANATOMY. ABDOMINAL AORTA. BLOOD SUPPLY OF GIT. LYMPHATIC DRAINAGE. ENTERIC NERVOUS SYSTEM. Dr Viktoriia Yerokhina, Lecturer in Medical Sciences [email protected]  LEARNING OUTCOMES ANAT.24 – GIT...

XY2141. ANATOMY. ABDOMINAL AORTA. BLOOD SUPPLY OF GIT. LYMPHATIC DRAINAGE. ENTERIC NERVOUS SYSTEM. Dr Viktoriia Yerokhina, Lecturer in Medical Sciences [email protected]  LEARNING OUTCOMES ANAT.24 – GIT 1 ANAT.24.14 - Explain the location of the large intestine and its relationship to surrounding organs. ANAT.24.15 - Review the blood supply and the venous and lymphatic drainage of the large intestine. ANAT.24.16 - Compare the sympathetic, parasympathetic and sensory innervation of the foregut, midgut and hindgut. ANAT.24.17 - Discuss the anastomotic communications between vessels of the foregut and the midgut and between midgut and hindgut. ANAT.24.18 - Compare and contrast where stomach contents from a perforation of the posterior, versus the anterior, stomach wall will initially accumulate. ANAT.25 – GIT 2 ANAT.25.01 - List the blood vessels which may be eroded in ulceration of the posterior wall of the stomach. ANAT.25.02 - Identify the large artery at risk for injury/hemorrhage by a perforated ulcer in the posterior wall of the duodenal bulb (1st part of duodenum). ANAT.25.03 - Summarize the lymph nodes that may drain tumors in various parts of the small and large intestine. ANAT.25.04 - Name the contents of the hepatoduodenal ligament which will be gripped during a Pringle maneuver. ANAT.25.05 - Review the nerve pathways for pain in a patient with gastroesophageal reflux disease (Barrett's esophagus).  AORTA. INTRODUCTION *Revision slide from the last semester lecture Longest and largest artery of the human body Elastic artery Originates in the left ventricle, where gives off the coronary arteries that supply the heart. Continues into the cranially convex aortic arch, which gives off branches supplying the head, neck, and upper extremities. Descends in the thoracic cavity and gives off branches for the thoracic organs, thoracic wall and back. Passes through the diaphragm in front of the vertebral column. Last part of the aorta runs in the abdominal cavity; its branches supply the abdominal organs, abdominal wall, and back. Bifurcates into the right and left common iliac arteries, which supply the pelvis and lower extremities.  AORTA. INTRODUCTION 1. Ascending aorta (aorta ascendens) – T4–T3 2. Aortic arch (arcus aortae) – to the top of T2 3. Descending aorta (aorta descendens) – T3–L4 3.1 Thoracic aorta (aorta thoracica) – T3–T12 3.2 Abdominal aorta (aorta abdominalis) – T12–L4 *Revision slide from the last semester lecture  ABDOMINAL AORTA - AORTA ABDOMINALIS Course 1. Begins at the level of the aortic hiatus (T12) as the continuation of the thoracic aorta 2. Descends in front of the vertebral column, on the left of the inferior vena cava (IVC) 3. Bifurcates into the common iliac arteries at the level of the 4th lumbar vertebra Has parietal and visceral branches  ABDOMINAL AORTA - AORTA ABDOMINALIS Parietal branches 1. Inferior phrenic arteries – large paired artery supplying the inferior surface of the diaphragm 1.1 Right and left superior suprarenal arteries – several smaller arteries supplying the suprarenal gland 2. Lumbar arteries – 4 paired arteries; terminate in the muscles of the abdominal wall 3. Median sacral artery – unpaired artery – descends on the anterior surface of the sacrum to the coccyx  ABDOMINAL AORTA - AORTA ABDOMINALIS Paired visceral branches 4. Middle suprarenal artery 5. Renal artery – arises at the level of L1– runs across the psoas major and enters the hilum of the kidney 5.1 Inferior suprarenal artery 6. Ovarian artery - (just below the renal artery L2) – in females – supplies the ovary or 6. Testicular artery – in males – supplies the testis and epididymis  ABDOMINAL AORTA - AORTA ABDOMINALIS Unpaired visceral branches 7. Coeliac trunk – supplies the abdominal part of the oesophagus, stomach, spleen, liver, bile ducts, oral half of the duodenum, and the majority of the pancreas 8. Superior mesenteric artery – supplies the aboral half of the duodenum, inferior part of the pancreatic head, jejunum, ileum, caecum, ascending colon, and 2/3 of the transverse colon 9. Inferior mesenteric artery – supplies the left 1/3 of the transverse colon, descending colon, sigmoid colon, and the majority of the rectum. ABDOMINAL AORTA - AORTA ABDOMINALIS  OVERVIEW OF THE GUT EMBRYOGENESIS Large intestine is derived from the midgut, hindgut, and cloaca. Derivatives of the midgut: cecum, appendix, ascending colon, and proximal two-thirds of the transverse colon. Derivatives of the hindgut: descending colon, sigmoid colon, rectum, distal third of the transverse colon, and the portion of the anal canal above the pectinate line. Derivative of the cloaca (ectoderm): portion of the anal canal distal to the pectinate line.  COELIAC TRUNK – TRUNCUS COELIACUS One centimeter long trunk arising from the anterior side of the abdominal aorta at the level of T12 to L1. Celiac artery is the blood supply to the structures derived from the foregut. It trifurcates into three main branches that supply the abdominal part of the oesophagus, stomach, spleen, liver, bile ducts, oral half of the duodenum, and the majority of the pancreas.  MAIN BRANCHES OF COELIAC TRUNK 1. Left gastric artery – runs along the superior margin of the pancreas and the lesser curvature, where it anastomoses with the right gastric artery forming the gastric arch 2. Common hepatic artery – arises from the coeliac trunk, travels to the right and divides above the pylorus 3. Splenic artery – runs to the left along the superior pancreatic margin to the splenic hilum. Mnemonic: Left Hand Side COELIAC TRUNK – TRUNCUS COELIACUS  BLOOD SUPPLY OF THE STOMACH Arterial supply: coeliac trunk Anastomosis along the lesser curvature: 1. Left gastric artery (from coeliac trunk) 2. Right gastric artery (usually from hepatic artery proper) Anastomosis along the greater curvature: 3. Left gastro-omental (gastro-epiploic) artery (from splenic artery) 4. Right gastro-omental (gastro-epiploic) artery (from gastroduodenal artery) Other branches: 5. Short gastric arteries (from splenic artery) – to the fundus and body 6. Pyloric artery (from hepatic artery proper) – to the anterior surface of the pylorus.  Stomach is supplied with arterial blood from the celiac trunk and its branches. Veins of the stomach drain into the portal vein. Innervated by the sympathetic and parasympathetic nervous system, as well as the myenteric plexus and submucous plexus of the enteric nervous system.  LYMPHATIC DRAINAGE Coeliac lymph nodes which are the primary drainage point for lymph from the stomach → in a malignancy of the stomach, the coeliac lymph nodes are the most likely to be involved. Coeliac lymph nodes (subsequently to the thoracic duct) and into the left supraclavicular lymph nodes (lymph nodes of Virchow-Troisier). body of the stomach: right and left gastric lymph nodes, right and left gastro-omental lymph nodes fundus: pancreaticosplenic lymph nodes, pylorus: pyloric lymph node.  CLINICAL CORRELATION Nodes of Virchow-Troisier are the left supraclavicular lymph nodes. Enlargement of these nodes can be one of the first symptoms of stomach cancer (Troisier’s sign) due to its connection with the thoracic duct (or cancer of other parts GIT). Gastric carcinoma (gastric cancer) commonly occurs in the region of pyloric antrum along the greater curvature of the stomach. A 72-year-old man with enlarged cervical lymph nodes has a malignant tumor of the cecum in the right lower quadrant of his abdomen. Which of the following lymph nodes of the neck is most frequently associated with malignant tumors of the gastrointestinal tract? A. Left inferior deep cervical B. Left supraclavicular C. Right inferior deep cervical D. Right supraclavicular E. Jugulodigastric  BLOOD SUPPLY OF THE SMALL INTESTINE With the exception of the proximal duodenum, which is supplied by the celiac trunk, the main arterial supply for the small intestine is provided by branches of the superior mesenteric artery. Veins of the small intestine drain into the portal vein and the lymphatics eventually drain into the superior mesenteric and celiac lymph nodes. Small intestine is innervated by the sympathetic and parasympathetic NS, as well as the myenteric plexus and submucous plexus of the enteric nervous system.  OVERVIEW Superior mesenteric artery supplies the midgut; inferior mesenteric artery supplies the hindgut. Veins of the midgut and hindgut derivatives drain into the portal vein. Distal anal canal is supplied by the internal pudendal artery and drains into the inferior vena cava. Mesenteric lymph nodes receive lymphatic drainage from the colon. Internal iliac and inguinal lymph nodes drain lymph from the rectum and anal canal. Large intestine is innervated by the autonomic nervous system (mesenteric plexus), except for the distal anal canal, which receives somatic innervation from the pudendal nerve. BLOOD SUPPLY OF DUODENUM Coeliac trunk and branches form the anterior and posterior pancreatic arches 1. Superior anterior pancreaticoduodenal artery (from gastroduodenal artery) 2. Superior posterior pancreaticoduodenal artery (from gastroduodenal artery) 3. Inferior pancreaticoduodenal artery (from superior mesenteric artery) Venous drainage: hepatic portal vein Lymphatic drainage: pyloric, hepatic and superior mesenteric lymph nodes (into the coeliac lymph nodes).  CLINICAL CORRELATION Splenic artery may be subject to erosion by a penetrating ulcer of the posterior wall of the stomach into the lesser sac. Left gastric artery may be subject to erosion by a penetrating ulcer of the lesser curvature of the stomach. Gastroduodenal artery may be subject to erosion by a penetrating ulcer of the posterior wall of duodenal ‘cap’ (D1). A 38-year-old man comes to the physician because of a 4-week history of intermittent burning epigastric pain. His condition worsened after a party where he drank alcohol. His pain improves with antiacid use and eating but returns approximately 2 hours following meals. Examination shows a deep ulcer located on the posterior wall of the duodenal bulb. Which component this ulcer can erode into? A. Gastroduodenal artery B. Liver capsule C. Left gastric artery D. Splenic vein E. Splenic artery F. Lumbar artery  SUPERIOR MESENTERIC ARTERY Superior mesenteric artery - second unpaired branch of the abdominal aorta. It is the artery of midgut. Supplies the aboral half of the duodenum, inferior half of the head of the pancreas, jejunum, ileum, caecum, vermiform appendix, and ascending colon. Supplies the right two-thirds of the transverse colon and anastomoses with a branch of the inferior mesenteric artery.  SUPERIOR MESENTERIC ARTERY Origin: from front of aorta at the lower border of L1. Branches and distribution o 12 or more jejunal and ileal arteries from its convex aspect to jejunum and ileum. o Inferior pancreaticoduodenal artery to lower half of head of pancreas and adjoining part of duodenum. o Middle colic artery to transverse colon. o Right colic artery to ascending colon, right colic flexure, and proximal part of transverse colon. o Ileocolic artery to caecum, vermiform appendix, beginning of ascending colon, and termination of ileum.  BLOOD SUPPLY OF JEJUNUM AND ILEUM Superior mesenteric artery supplies the jejunum and ileum via jejunal and ileal arteries SMA usually arises at the level of the L1 vertebra, approximately 1 cm inferior to the celiac trunk, and runs between the layers of the mesentery, sending 12–15 branches to the jejunum and ileum. Arteries unite to form loops or arches, called arterial arcades → give rise to straight arteries, called vasa recta.  BLOOD SUPPLY OF JEJUNUM AND ILEUM Jejunum: longer vasa recta, fewer and larger arcades Ileum: shorter vasa recta, more and smaller arcades  INFERIOR MESENTERIC ARTERY Inferior mesenteric artery is the third unpaired branch of the abdominal aorta. Originate at the level of L3. Supplies the left third of the transverse colon, descending colon, sigmoid colon. Continues to the pelvis as the superior rectal artery supplying the majority of the rectum.  INFERIOR MESENTERIC ARTERY It is the artery of hindgut Origin: from front of aorta at the level of L3 Branches and distribution o Left colic artery to the terminal part of transverse colon, left colic flexure, and upper part of descending colon. o Sigmoid arteries (2 to 4 in number) to the lower part of descending colon and sigmoid (pelvic) colon. o Superior rectal artery to the upper part of rectum.  INFERIOR MESENTERIC ARTERY 2.1 Left colic artery (a. colica sinistra) – supplies the descending colon and anastomoses with the middle colic artery close to the left colic flexure 2.2 Sigmoid arteries (a. sigmoideae) – two to four arteries supplying the sigmoid colon 2.3 Superior rectal artery (a. rectalis superior) – a terminal branch of the inferior mesenteric artery while crossing the linea terminalis – supplies the rectal ampulla INFERIOR MESENTERIC ARTERY  DRANAIGE Venous drainage: superior mesenteric vein (into hepatic portal vein) Lymphatic drainage: starts in lacteal superior mesenteric lymph nodes (into coeliac and lumbar lymph nodes and subsequently into the thoracic duct).  CLINICAL CORRELATION Abdominal aortic aneurysm (AAA) is a focal dilatation of the abdominal aorta to more than 1.5 times its normal diameter. AAAs are classified by location as: suprarenal infrarenal. Risk factors: Smoking (most important risk factor) Advanced age Atherosclerosis Hypercholesterolemia and arterial hypertension Positive family history Male sex Trauma  CLINICAL CORRELATION AAAs are frequently asymptomatic and therefore detected incidentally. Symptomatic AAAs can manifest with lower back pain, a pulsatile abdominal mass, and a bruit on auscultation. Abdominal ultrasound is the best initial and confirmatory test to diagnose AAAs and determine their extent. AAA rupture typically presents with sudden onset of severe tearing back or abdominal pain, a painful pulsatile mass, and hypovolemic shock, and should be managed with emergent surgery. All men between 65 and 75 years of age with a history of smoking should be screened once with an ultrasound to exclude an AAA. An 80-year-old man is admitted to the hospital with hypertension. His history includes a notation that he has had a poor appetite for some time. During physical examination it is observed that his blood pressure is 175/95 mm Hg and that he has a marked pulsation in his epigastric region. Which diagnosis will explain these symptoms and signs? A. Aortic aneurysm B. Cirrhosis of the liver C. Hiatal hernia D. Kidney stone E. Splenomegaly  ABDOMINAL LYMPH NODES Parietal lymph nodes 1. Left lumbar lymph nodes 1.1 Lateral aortic, preaortic, postaortic lymph nodes 2. Intermediate lumbar lymph nodes 3. Right lumbar lymph nodes 3.1 Lateral caval, precaval, retrocaval lymph nodes 4. Inferior diaphragmatic lymph nodes 5. Inferior epigastric lymph nodes  ABDOMINAL LYMPH NODES Visceral lymph nodes 1. Gastric, gastroomental, pyloric and pancreaticoduodenal lymph nodes 2. Pancreatic lymph nodes 3. Splenic lymph nodes 4. Hepatic lymph nodes 5. Superior mesenteric lymph nodes (juxta- intestinal, central superior mesenteric, ileocolic, precaecal and retrocaecal, appendicular, mesocolic and paracolic, right, midle and left colic) 6. Inferior mesenteric (sigmoid, superior rectal). BLOOD SUPPLY AND INNERVATION OF SMALL INTESTINE BLOOD SUPPLY OF LARGE INTESTINE  ENTERIC NERVOUS SYSTEM Enteric nervous system has complex networks of afferent and efferent nerve fibers. Can operate independently of the brain and the spinal cord but its activity is usually modulated by the sympathetic and parasympathetic nervous systems. Sympathetic system has an inhibitory effect on the GIT Parasympathetic system promotes secretion and motility. However, removal of vagal or sympathetic connections with the GIT only has a minor effect on GI function because of the autonomy of the enteric nervous system.  ENTERIC NERVOUS SYSTEM Consists of: Enteric ganglia Plexuses of the GI tract 1. Submucosal plexus (Meissner plexus) found in submucosa 2. Myenteric plexus (Auerbach plexus) found in muscularis between circular and longitudinal muscle layers Interstitial cells of Cajal (ICCs) Located in the wall of the intestine Act as pacemaker cells for peristaltic motor activity of the gut Connected to smooth muscle cells via gap junctions Generate spontaneous electrical slow waves and thus rhythmic contractions of the smooth musculature (i.e., peristalsis).  ENTERIC NERVOUS SYSTEM Structure Efferent neurons, afferent neurons, and interneurons Derived from neural crest cells Transmitter: e.g., acetylcholine, dopamine, and serotonin Functions: Control of GI secretion and motility Promote GI secretions for digestion Allow sphincter relaxation for food to pass Stimulate GI peristalsis. MCQ FOR SELF-CONTROL https://forms.gle/K9scymDhNivajnRo6 REFERENCES Anatomy inspires…