9. Gross Anatomy Of Small Intestine & Large Intestine

Front 1

Gross morphology of duodenum

Back 1

Situated in epigastric & umbilical region.

C shaped.

First inch of the duodenum has peritoneum, the rest is retroperitoneal.

Lesser omentum on its upper border.

Greater omentum on its lower border.

Front 2

Parts of Duodenum

Back 2

Supra-ampullary - above the opening of common bile duct from foregut

Infra-ampullary - below the opening of common bile duct from midgut

Front 3

Duodeno-jejunal flexure

Back 3

Marked by fibromuscular band called "Suspensory ligament of Treitz"

Functions:

1. Supports the Duodeno-jejunal junction

2. Widens its angle

3. Identity of duodenal termination

Front 4

Inferior of duodenum

Back 4

Plicae circulares of mucous membrane are large and numerous.

Ampulla open on its middle & postermedial wall (major duodenal papilla).

Ampulla open on its middle & postermedial wall (major duodenal papilla).If accessory pancreatic duct present, open on minor duodenal papilla.

If accessory pancreatic duct present, open on minor duodenal papilla.

Front 5

Arterial supply of duodenum

Back 5

1. Supra-ampullary part of duodenum is supplied by superior pancreatico-duodenal artery (from gastroduodenal artery)

2. Infra-ampullary part of duodenum is supplied by inferior pancreatico-duodenal artery (from superior mesenteric artery)

Front 6

Applied anatomy of duodenum

Back 6

1. Duodenal ulcers located in duodenal ampulla or cap.

2. Erosion of a duodenal ulver involve gastro-duodenal artery.

3. Duodenal stenosis - CA pancreas

4. Duodenal cap - Barium meal appearance of xray

Front 7

Root of the mesentery crosses

Back 7

1. Horizontal part of duodenum

2. IVC and aorta

3. Right psoas major muscle

4. Right ureter

5. Right gonadal (testicular or ovarian vessels)

Front 8

Blood supply of small intestine

Back 8

Arterial supply

- supplied by superior mesenteric artery

- superior mesenteric artery arises from abdominal aorta

- branches into jejunum & ileum, then unite to arise vasa recta & pass to the gut.

Venous drainage

- superior mesenteric vein drains the jejunum & ileum.

- terminates behind the neck of the pancreas by uniting with splenic vein to form portal vein.

Front 9

Innervation of small intestine

Back 9

Presynaptic sympathetic fibers T5 to T9 synapse in celiac & superior mesenteric ganglia, through the sympathetic trunks and greater splancnic nerves.

Parasympathetic by vagus nerve derive from posterior vagal trunk.

Front 10

Applied anatomy of Small intestine

Back 10

1. Small intestine can be excised to 1/3 of its length.

2. Commonest site for worm infestation.

3. In typhoid, the peyer's patches become swollen & ulcerated.

4. Congenital anomalies - Meckel's diverticulum, omphalocoele, umbilical hernia.

5. Intestinal obstruction - worms, volvulus.

Front 11

Meckel diverticulum

Back 11

Congenital remnant of proximal part of embryonic yolk stalk anomaly.

Fingerlike pouch on the antimesenteric border of ileum.

Pain mimicking produced by appendicitis pain

Front 12

Flexures of the large intestine

Back 12

Hepatic flexure - with right lobe of the liver

Splenic flexure - with inferior of lower end of spleen.

Front 13

Main characteristics features of Large Intestine

Back 13

1. It has three thick bands of longitudinal muscles called taenia coli.

2. The sacculations of its wall between the taenia coli are called "haustra" caused by the tone of the taenia coli.

3. Small pouches of peritoneum filled with fat called "appendices apiploicae"

Front 14

The caecal fossae

Back 14

Retro or subcaecal fossa - posterior to caecum.

Ileo-colic or superior ileocaecal fossa - is formed by a fold of peritoneum produced by anterior caecal artery.

Inferior ileocaecal fossa - is formed by the ileocaecal or bloodless fold of Trves. It is open to the left.