Duodenum

• Duodenum


  First & shortest part of the small intestine
• Duodenum


  • Widest and fixed part
  • C-shaped, about 10 inches long (25 cm)
  • Begins at the pylorus on the R side and ends at the duodeno-jejunal junction on the left side (L2 vertebra)
• Divisions of the duodenum

  1. Superior (1st) part - 5cm & lies anterolat. to the body of L1

  2. Descending (2nd) - 7 to 10cm & descends along the R sides of L1 through L3

  3. Horizontal (3rd) - 6 to 8cm & crosses L3

  4. Ascending (4th) - 5cm & begins at the L of L3 and rises superiorly as far as superior border of L2
• Duodenum - Second part

  • Laterally: Right colic flexure
  • Medially: Head of pancreas, Anastomoses of Superior and Inferior pancreaticoduodenal vessels, Bile duct and main pancreatic duct
• Blood supply to the pancreas

  • Upper part - superior pancreaticoduodenal from gastroduodenal
  • Lower part - inferior pancreaticoduodenal from superior mesenteric
• Duodenal compression


  • The superior mesenteric vessels may compress the horizontal part / 3rd of the duodenum;patients experience epigastric pain, nausea after meal and bilious vomiting
• Venous drainage


  1. Superior pancreaticoduodenal vein drains into portal vein

  2. Inferior pancreaticoduodenal joins the superior mesenteric vein
• Lesser curvature of stomach

  R & L gastric arteries
• Greater curvature of stomach

  R & L gastroepiploic arteries
• Fundus of stomach


  Short gastric artery
• First part of duodenum

  Gastroduodenal artery
• Proximal portion of duodenum + superior part of head of pancreas

  Superior pancreaticoduodenal artery (from gastroduodenal a.)
• Distal portion of duodenum + head of pancreas

  Inferior pancreaticoduodenal artery (from SMA)
• Nerve supply of the stomach

  • Parasympathetic nerve supply is from the anterior vagal trunk from the Left Vagus nerve and posterior vagal trunk from the Right vagus nerve which enter the abdomen through esophageal hiatus
  • Sympathetic nerve supply is from T6 to T9 segments of the spinal cord
• Gastric ulcers


  Most often occur within the body of the stomach along the lesser curvature above the incisura angularis
• Carcinomas of the stomach

  Most commonly found in the pylorus
• Nasogastric intubation


  1. To empty, decompress the stomach; obtain sample of gastric juice

  2. Patient is placed in semi upright or left lateral position

  3. From the nostril to cardiac orifice of stomach – 17.2 inches / 44 cm
• Gastric ulcers


  Most often occur within the body of the stomach along the lesser curvature above the incisura angularis
• Carcinomas of the stomach

  Most commonly found in the pylorus
• Nasogastric intubation


  1. To empty, decompress the stomach; obtain sample of gastric juice

  2. Patient is placed in semi upright or left lateral position

  3. From the nostril to cardiac orifice of stomach – 17.2 inches / 44 cm
• Duodenal ulcers


  Most often occur on the anterior wall of the first part of the duodenum followed by the posterior wall
• Perforation of the duodenum

  Occur most often with ulcers on the anterior wall; less often with ulcers on the posterior wall (may erode the gastroduodenal artery causing severe hemorrhage and perforate into the pancreas)
• GASTRIC


  • Bleeding from left gastric artery
  • Burning epigastric pain soon after eating
  • Pain increases with food intake
  • Pain relieved by antacids
• Duodenal

  • Bleeding from gastroduodenal artery
  • Burning epigastric pain 1 – 3 hrs after eating
  • Pain decreases with food intake
  • Pain relieved by antacids
  • Patient wakes at night because of pain
• Hematemesis


  Vomiting of blood, commonly results from bleeding into the lumen of the esophagus, stomach or duodenum proximal to the ligament of Trietz; commonly caused by duodenal ulcer, gastric ulcer or esophageal varices
• Hematochezia


  Blood in the stool, usually results from bleeding into the lumen of the jejunum, ileum, colon or rectum distal to the ligament of Trietz
• Jejunum


  Proximal 2/5 of the small intestine, begins at the duodeno-jejunal flexure
• Ileum


  Distal 3/5 of the small intestine, ends at the ileocecal junction
• The small intestine is 20ft / 6 meters long
• Jejunum


  • Lies in the left upper quadrant (LUQ)
• Ileum


  • Lies in the right lower quadrant (RLQ)
• Superior mesenteric artery


  • Originates from the abdominal aorta at level L1
  • Sends 15 to 18 branches
  • Branches unite to form loops - arterial arcades
  • Arterial arcades give rise to vasa recta
• Jejunum characteristic


  • Color: Deeper red
  • Caliber: 2–4cm
  • Wall: Thick & heavy
  • Vascularity: Greater
  • Vasa Recta: Long
  • Arcades: Few, large
  • Fat: Less
  • Plicae circularis: Large, tall
  • Lymphoid nodules: Few
• Ileum


  • Color: Paler pink
  • Caliber: 2–3cm
  • Wall: Thin & light
  • Vascularity: Less
  • Vasa Recta: Short
  • Arcades: Many
  • Fat: More
  • Plicae circularis: Low, sparse – absent in distal
  • Lymphoid nodules: Many
• Jejunum


  • Proximal 2/5 of small intestine
  • Thicker walls
  • Longer plicae circulares
  • (+) "windows" between blood vessels of mesentery
  • Longer vasa recta
• Ileum


  • Distal 3/5 of small intestine
  • Occupies the false pelvis in right lower quadrant
  • Peyer patches
  • More prominent arterial arcades
  • Meckel's diverticulum
• Intussusception


  Part of the small intestine invaginates into an adjacent distal segment (intussuscipiens)
• Types of intussusception


  • Jejunoileal
  • Ileoileal
  • Ileocecal (most common)
• Intussusception


  • More common in children
  • May be caused by hyperplasia of lymphatic tissue in the wall of ileum
• Intussusception


  • Severe, intermittent abdominal pain alternating with periods of no pain
  • Palpable RUQ mass
  • Vomiting
  • Currant jelly stools