Flipped Session 11 PDF

Flipped Session 11  anterolateral abdominal wall - layers - skin - subcutaneous fascia - major site of fat storage - superior to umbilicus – like most regions of body - inferior to umbilicus: - deepest part has dense elastic/collagen fiber network - two l...

Flipped Session 11  anterolateral abdominal wall - layers - skin - subcutaneous fascia - major site of fat storage - superior to umbilicus – like most regions of body - inferior to umbilicus: - deepest part has dense elastic/collagen fiber network - two layers: - Camper’s fascia - superficial fascia - fatty - Scarpa’s fascia - deep membranous layer - strong layer – used for surgical closure due to strength - continuous into perineum as Colle’s fascia - muscles within investing fascial layers + aponeuroses = like Intercostal space muscle layers - external oblique - internal oblique - transversus abdominis - transversalis fascia (endo-abdominal fascia) - parietal peritoneum (serosal membrane) - peritoneal cavity  Relation of aponeurosis to rectus abdominis It covers the whole anterior aspect of rectus abdominis  Relation of internal oblique aponeurosis to rectus abdominis Between the costal margin and a point midway between the umbilicus and symphysis pubis The aponeurosis divides at the lateral External border of rectus abdominus into 2 laminae (ant. & post) oblique Internal oblique aponeurosis The anterior lamina extends from costal margin to sym. pubis The posterior lamina stops midway X between umbilicus and sym. Pubis ( arcuate line ) Source: Atlas of Anatomy (2nd edition)  Relation of Transversus abdominis aponeurosis to rectus abdominis Between the costal margin and a point midway between the umbilicus and symphysis pubis The aponeurosis passes behind rectus abdominus Below a point midway between the umbilicus & symphysis pubis The aponeurosis passes in front X rectus abdominus Fascia tranversalis Formation Transversus External oblique abdominus Internal oblique External oblique Transversus abdominus Internal oblique Arcuate line Posterior Side of Anterior Abdominal Wall: Folds (and ligaments) Falciform ligament- connects anterior abdominal wall to liver Median umbilical fold- contains urachus (remnant of allantoic duct) Medial umbilical fold- contains remnant of umbilical artery Lateral umbilical fold- overlies the inferior epigastric vessels Cutaneous Innervation All these nerves terminate by supplying skin as follows: T7-T9- from xiphoid process to just above umbilicus T10- skin around umbilicus T11, T12, and L1 just below umbilicus to (and including) the pubic area Ilioinguinal nerve (L1) also supplies anterior surface of scrotum or labia majora and sends small cutaneous branches to the thigh  BOUNDARIES OF INGUINAL CANAL. ANTERIOR WALL IN ITS WHOLE EXTENT Skin Superficial fascia External oblique aponeurosis IN LATERRAL ONE-THIRD Fibres of internal oblique  BOUNDARIES OF INGUINAL CANAL POSTERIOR WALL ENTIRELY FORMED BY Fascia transversalis MEDIAL-HALF Conjoint tendon MEDIAL ONE -FOURTH Reflected part of inguinal ligament  Transversus abdominis roof Arched fibers of the internal oblique and transversus abdominis muscle. Internal oblique Floor Grooved upper surface of the inguinal ligament, Medial end: upper surface of the lacunar ligament. Grooved surface Fasciae of Spermatic Cord From deep to superficial: Internal spermatic fascia - Deepest layer - Arises from transversalis fascia - Attaches to margins of deep inguinal ring Cremasteric fascia - Middle fascial layer - Associated with cremasteric muscle - Arises from internal oblique muscle External spermatic fascia - Most superficial layer - Arises from aponeurosis of external oblique muscle - Attached to margins of superficial inguinal ring Cremasteric Reflex Cremaster muscle Action: elevates testes Innervation: genital branch of genitofemoral nerve Cremasteric Reflex Contraction of cremaster muscle can be stimulated by a reflex arc Touching the skin at or around the anterior aspect of superior thigh stimulates sensory fibers in ilioinguinal nerve Sensory fibers enter spinal cord at L1 level Afferent limb- ilioinguinal n. which then causes stimulation of motor Efferent limb- genital branch of fibers in genital branch of genitofemoral genitofemoral nerve nerve causing contraction of cremaster muscle and elevation of testis  INGUINAL INGUINALTRIANGLE TRIANGLEOFOF HESSELBACH. HESSELBACH. Peritoneal triangle in the posterior wall of the inguinal canal. BOUNDARIES Lateral – Inferior epigastric artery. Medial – Lateral border of rectus abdominis. Inferior – Inguinal ligament.  INGUINAL HERNIA INDIRECT DIRECT Indirect Inguinal Hernia Most common of the 2 types of inguinal hernias Occurs much more frequently in men than women Protruding peritoneal sac enters the inguinal canal by passing through the deep inguinal ring, just lateral to inferior epigastric vessels Since it enters the spermatic cord it will be covered by spermatic fasciae and descends into the scrotum Direct Inguinal Hernia Protruding peritoneal sac enters medial end of inguinal canal directly through abdominal wall Bulging occurs medial to the inferior epigastric vessels in area known as inguinal triangle (Hesselbach’s triangle) Inguinal triangle boundaries are: - lateral- inferior epigastric vessels - Medial- rectus abdominis muscle - Inferior- inguinal ligament Direct inguinal hernias do not traverse entire length of inguinal canal but may exit superficial inguinal ring  Lesser Omentum Hepatogastric ligament Hepatoduodenal ligament  Fold of peritoneum extending from: - lesser curvature of stomach and first 2 cm of duodenum to the liver. 2 parts: Hepatogastric and hepatoduodenal. Contents: Hepatic artery proper. Portal vein Bile duct Lymph nodes and lymphatics and Hepatic plexus of nerves Right and left gastric vessels Gastric group of lymph nodes and gastric nerves.  Liver Lesser omentum Stomach Lesser Greater curvature curvature Greater omentum  Omental (Epiploic) foramen Bounded: Anteriorly: The portal vein, hepatic artery proper, and bile duct. Posteriorly: Inferior vena cava. Superiorly: Caudate lobe of the liver. Inferiorly: first part of the duodenum Epiploic foramen  Left anterior Right anterior intraperitoneal space intraperitoneal space Left posterior intraperitoneal space (lesser sac) Right posterior intraperitoneal space (Morison's pouch or hepato renal pouch) The right & left anterior subphrenic spaces lie between the diaphragm and the liver, on each side of the falciform ligament. The right posterior subphrenic space lies between the right lobe of the liver, the right kidney, and the right colic flexure. Left posterior subphrenic space is the upper part of the lesser sac Pouches : A- Male : rectovesical pouch B- female : Rectouterine pouch (Douglas pouch) Vesicouterine pouch Douglas pouch: As it is the furthest point of the abdominopelvic cavity in women, it is a site where infection and fluids typically collect.  In recumbent position: The most dependent parts of the peritoneum are the hepato-renal pouch and the recto-uterine pouch in the females and rectovesical pouch in males. After operative procedures the patient is kept in propped up position to encourage gravitation of peritoneal fluid in the pelvic cavity from which absorption of infected fluid is less. Hepatorenal pouch of morison Rectouterine pouch of douglas  Celiac Trunk Distribution Supplies the foregut: Abdominal esophagus Stomach Duodenum* Liver Spleen Gallbladder Pancreas* *These organs will be discussed in future lectures  Curvatures Short gastric artery Left gastric artery Left gastro- epiplioc Right gastric artery artery Includes: - Left gastric a. (celiac trunk) - Right gastric a. (hepatic artery proper) - Right gastro-omental a. (gastroduodenal a.) Right gastro- - Left gastro-omental a. (splenic a.) epiplioc artery - Short gastric a. (splenic a.)  Posterior relations Left kidney Stomach bed Splenic artery Spleen Transverse mesocolon Pancreas Transverse colon  Gastric ulcers : occur in the alkaline- producing mucosa of the stomach, usually on or close to the lesser curvature. A chronic ulcer invades the muscular coats and, in time, involves the peritoneum so that the stomach adheres to neighboring structures. An ulcer situated on the posterior wall of the stomach may perforate into the lesser sac or become adherent to the pancreas. Erosion of the pancreas produces pain referred to the back. The splenic artery runs along the upper border of the pancreas, and erosion of this artery may produce fatal hemorrhage  Cholecystitis Incidence Female Fatty Fertile Forties Fatty meals  Pain in the tip of right shoulder Pain in the right Pain in the Pain at the back hypochondrium epigastric region below scapula Is felt in the right hypochondrium and radiates to: Pain of The tip of right shoulder At the back (below the scapula) cholecystitis Epigastric region  Superior Mesenteric Artery Supplies the midgut Branches off aorta anteriorly about 1cm inferior to celiac trunk (L1 vertebral level) Is crossed anteriorly by splenic vein and neck of the pancreas Posterior to superior mesenteric a. are the left renal vein, uncinate process of pancreas, and inferior (3rd) part of duodenum Superior Mesenteric Artery Distribution Branches include: - Inferior pancreaticoduodenal a. - Jejunal and ileal arteries (Intestinal arteries) - Middle colic a. - Right colic a. - Ileocolic a.  Inferior Pancreaticoduodenal Artery First branch of superior mesenteric artery Divides immediately into anterior and posterior branches These branches ascend on the corresponding sides of the pancreas They anastomose as follows: Anterior inferior pancreaticoduodenal with anterior superior pancreaticoduodenal aa. Posterior inferior pancreaticoduodenal with posterior superior pancreaticoduodenal aa. This arterial network supplies the head and uncinate process of the pancreas and the duodenum Marginal Artery (of the Colon) Forms an important anastomoses between superior and inferior mesenteric arteries Clinically important because it provides collateral supply to the colon, maintaining blood supply to the colon in case of occlusion or stenosis of one of the major arteries Superior Mesenteric Artery Syndrome Occurs when the angle between the superior mesenteric artery and aorta is too acute Compresses 3rd part of duodenum and may cause obstruction Parts of the duodenum Most inflammatory erosions of the duodenal wall, duodenal ulcers, are in the posterior wall of the superior part of the duodenum within 3 cm of the pylorus. Occasionally, an ulcer perforates the duodenal wall, permitting its contents to enter the peritoneal cavity and produce peritonitis. Because the superior part of the duodenum closely relates to the liver and gallbladder, either of them may adhere to and be ulcerated by a duodenal ulcer. Erosion of the gastroduodenal artery, a posterior relation of the superior part of the duodenum, by a duodenal ulcer results in severe hemorrhage into the peritoneal cavity.  Meckel’s diverticulum A Meckel’s diverticulum is A remnant of the proximal part of the embryonic omphaloenteric duct (yolk stalk), the diverticulum usually appears as a finger-like pouch  Epidemiology Meckel's diverticulum is the most prevalent congenital anomaly of the GI tract (Rule of 2) ❖ 2% of the general population ❖ 2% prevalence, 2:1 male predominance ❖ 2 ft proximal to the ileocecal valve in adults ❖ 50% symptomatic under 2 years ❖ Heterotropic tissue ▪ Gastric mucosa ▪ Pancreatic acini  Clinical Presentation ❖ Asymptomatic ❖ Bleeding is the most common presentation in children acid-producing from heterotopic gastric mucosa located within the diverticulum. ❖ Intestinal obstruction; ❖ Diverticulitis General characteristics of large intestine 1. It has a large internal diameter compared to that of the small intestine. 2. Peritoneal-covered accumulations of fat (the omental appendices) are associated with the colon. 3. The segregation of longitudinal muscle in its walls into three narrow bands (the taeniae coli), which are primarily observed in the cecum and colon and less visible in the rectum. 4. The sacculations of the colon (the haustra of the colon). Inferior Mesenteric artery The inferior mesenteric artery is the artery of hindgut. It arises from the anterior aspect of the aorta at about the level of third lumbar vertebra (L3) 3 or 4 cm above the aortic bifurcation. It supplies left one-third of transverse colon, descending colon, sigmoid colon, rectum and part of anal canal above the anal valves. It branches include: Left colic artery Sigmoid arteries Superior rectal artery McBurney’s Point - Refers to a point at the junction of the lateral and middle 1/3 of a line from anterior superior iliac spine to the umbilicus - People with appendicular problems may describe pain near this location - During an appendectomy the iliohypogastric nerve is likely to be injured to its location near McBurney’s point Appendicitis Acute inflammation of the appendix is a common cause of an acute abdomen (severe abdominal pain arising suddenly). Digital pressure over the McBurney point produces the maximum abdominal tenderness. The pain of appendicitis usually commences as a vague pain in the peri-umbilical region because afferent pain fibers enter the spinal cord at the T10 level. Later, severe pain in the right lower quadrant results from irritation of the parietal peritoneum lining the posterior abdominal wall. Diverticulosis Diverticulosis is a disorder in which multiple false diverticula (external evaginations or outpocketings of the mucosa of the colon) develop along the intestine. It primarily affects middle-aged and elderly people. Diverticulosis is commonly found in the sigmoid colon. Diverticula are subject to infection and rupture, leading to diverticulitis.  Hepatic Portal system Refers to venous blood from the following viscera passing through a 2nd vascular bed, in the liver, before ultimately entering systemic venous system (inferior vena cava): Drains – Gastrointestinal tract (except lower part of anal canal) – Spleen, Pancreas and gall bladder Conveys absorbed products of digested food to liver Blood passes through the liver until it reaches the hepatic vv. Hepatic vv. return blood to inferior vena cava just below diaphragm Portal Vein Formed by union of (behind the neck of pancreas) 1. Superior Mesenteric Vein 2. Splenic vein Tributaries: 1. Left gastric vein 2. Right gastric vein 3. Cystic veins 4. Paraumbilical veins Portal vein collects poorly oxygenated but nutrient-rich blood and carries it to liver. Portal vein provides 70-80% of blood supply to liver (20- 30% provided by hepatic artery proper) SITES OF PORTACAVAL ANASTOMOSIS Refers to communications between the portal and systemic venous systems. If pressure in portal vein is elevated, venous enlargements (varices) occur at and around these sites (e.g. caput medusa) Five sites of portal/systemic circulation : 1. Lower third of the Esophagus 2. Paraumbilical Area 3. Upper end of Anal canal 4. Retroperitonial 5. Bare area of liver  1. Lower third of the Esophagus Theesophageal branches of the left gastric vein (portal tributaries) anastomose with the esophageal veins draining the middle third of the esophagus into the azygos veins.(systemic tributaries) 2. Paraumbilical Area They connect the left branch of the portal vein with the superficial veins of the anterior abdominal wall. (systemic tributaries) 3. Anal canal The superior rectal veins (portal tributary) draining the upper half of the anal canal anastomose with the middle and inferior rectal veins (systemic tributaries).  Esophageal varices High blood pressure in the portal vein pushes blood into the surrounding blood vessels including those in the esophagus. The extra blood causes the veins in the esophagus to swell. These enlarged veins, called varices, can break open and bleed. Patient typically presents with Haematemesis & Black tarry stools. It can be visualized using (endoscopy). Caput Medusae Refers to a condition where swollen superficial veins radiate out from abdomen Occurs in patients who have an obstruction of inferior vena cava or hepatic portal vein  (Hemorrhoids Hemorrhoids are painful, swollen veins in the lower portion of the rectum or anus. Internal hemorrhoids- prolapses of rectal mucosa containing internal rectal venous plexus External hemorrhoids- thromboses (blood clots) in the veins of the external rectal venous plexus External tend to be painful (pudendal nerve) while internal are not Portosystemic Shunts Common method for reducing portal hypertension is to divert blood from portal venous system to systemic venous system This is done by creating a communication between the portal vein and IVC or by joining splenic and left renal veins creating a portosystemic shunt Parts Neck Body Tail Head Uncinate process  CBD IVC CBD IVC Posterior Inferior vana cava relations Common bile duct  Splenic vein Portal vein Superior mesenteric v Posteriorly Splenic and superior mesenteric veins unite to form portal vein  Left kidney Tail Lieno-renal ligament Tail of pancreas  Cancer head of pancreas CBD => obstructive jaundice IVC => LL edema Poral vein => portal hypertension Pylorus => stenosis. Duodenum => obstruction  Early stage, edema, congestion Stone in the ampulla of Advanced hemorrhagic pancreatitis, vater blood blebs, fat necrosis Cause: pancreatic disease (cancer or inflammation) Pancreatic Site: epigastric region & radiate to the back pain Character: increases by lying down & relieved on leaning forwards.  Peptic ulcer In the stomach or duodenum may be complicated by erosion of pancreas. Penetration of posterior wall ulcer of duodenum to pancreatic head