STOMACH ANATOMY PARTS OF STOMACH BLOOD SUPPLY OF

STOMACH

ANATOMY

PARTS OF STOMACH

BLOOD SUPPLY OF THE STOMACH • Left gastric artery, a branch of coeliac artery • Right gastric artery, a branch of hepatic artery. • Right gastroepiploic artery, a branch of gastro duodenal artery. • Left gastroepiploic artery, a branch of splenic artery. • Short gastric arteries, branches of splenic artery.

BLOOD SUPPLY OF STOMACH

VENOUS DRAINAGE OF STOMACH Right and left gastric veins drain into portal vein. Right gastroepiploic vein drains into superior mesenteric vein. Left gastroepiploic vein and short gastric veins drain into splenic vein. Prepyloric vein of Mayo distinguishes pyloric canal from the first part of duodenum.

NERVE SUPPLY • Intrinsic innervation occurs through myenteric plexus of Auerbach and submucous plexus of Meissner. • Right vagus is posterior and left vagus is anterior. • Posterior vagus gives criminal nerves of Grassi, which supply lower oesophagus and fundus of stomach, which, if not cut properly during vagotomy, may lead to recurrent ulcer

NERVE SUPPLY

• Gastroduodenal pain is sensed via sympathetic fibres (T 5 -T 10).

HISTOLOGY • The fundus and body contains parietal and chief cells. • Parietal cells secrete acid and intrinsic factor. • Chief cells produce pepsinogen. • In the antrum, endocrine cells produce gastrin (G cells) and somatostatin (D cells).

LYMPHATIC DRAINAGE

INVESTIGATION OF THE STOMACH AND DUODENUM

GASTRIC FUNCTION TESTS • Pentagastrin test/Kay’s augmented histamine test • Hollander’s insulin test • Radioisotope labelled gastric emptying study • 24 hours intragastric p. H monitoring • Gastrin level estimation

FLEIBLE ENDOSCOPY • Gold standard • Use a solid-state camera mounted at the instrument’s tip • More sensitive than conventional radiology • Diagnostic and theraputic • Complications

ENDOSCOPE

VIEW OF NORMAL STOMACH

CONTRAST RADIOLOGY • Barium meal / follow-through • CT with oral contrast

ULTRASONOGRAPHY • Standard ultrasound imaging - less sensitive than other modalities • Endoluminal ultrasound and laparoscopic ultrasound are probably the most sensitive techniques available in the preoperative staging of gastric cancer. – Depth of invasion – Enlarged lymph nodes – Liver metastasis

• An additional use of ultrasound is in the assessment of gastric emptying.

CT/MRI • Gastric wall thickening associated with a carcinoma of any reasonable size can be easily detected by CT, but the investigation lacks sensitivity in detecting smaller and curable lesions • Lymph node metastasis • Liver metastasis • Limitations

POSITRON EMISSION TOMOGRAPHY (PET) • Functional imaging technique that relies on the uptake of a tracer, by metabolically active tumour tissue • Fluorodeoxyglucose (FDG) isthe most commonly used tracer • Anatomical and functional information need to be linked - CT/PET • Preoperative staging of gastro-oesophageal cancer - often demonstrates occult spread

LAPAROSCOPY • Assessment of gastric cancer • Peritoneal assessment and cytology • Posterior extent may not be accessible

GASTRIC EMPTYING STUDIES • Useful for studying gastric dysmotility problems, particularly those that follow gastric surgery • A radioisotope-labelled liquid and solid meal is ingested and the emptying of the stomach is followed on a gamma camera • The proportion of activity in the remaining stomach to be assessed numerically, and it is possible to follow liquid and solid gastric emptying independently

ANGIOGRAPHY • Angiography is used most commonly in the investigation of upper gastrointestinal bleeding that is not identified using endoscopy. • Therapeutic embolisation may also be of value in the treatment of bleeding in patients in whom surgery is difficult or inadvisable