VASCULAR SUPPLY AND LYMPHATIC DRAINAGE
UPDATE Date Added: 21 June 2005
Shanida Helena Nataraja, PhD (Dianthus Medical Limited)
Abstract: Assessment of vascular anatomy around stomach before laparoscopy-assisted gastrectomy.
Click on the following link to view the abstract: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=15208129&query_hl=12 Assessment of vascular anatomy around stomach before laparoscopy-assisted gastrectomy.
Left gastric artery
The left gastric artery is the smallest branch of the coeliac axis. It ascends to the left of the midline and crosses the left crus of the diaphragm beneath the peritoneum of the upper posterior wall of the lesser sac. Here it lies adjacent to the left inferior phrenic artery and medial or anterior to the left suprarenal gland. It runs forwards into the superior portion of the lesser omentum adjacent to the superior end of the lesser curvature. It turns anteroinferiorly to run along the lesser curvature between the two peritoneal leaves of the lesser omentum. At the highest point of its course, it gives off an oesophageal branch. In its course along the lesser curvature, it gives off multiple branches that run onto the anterior and posterior surfaces of the stomach and anastomose with the right gastric artery in the region of the incisura angularis.
Figure 71.6 Double contrast barium meal. A, Initial stomach filling demonstrates a horizontally lying stomach with prominent gastric rugal folds. B, The area gastricae within the antrum are clearly identified on distension of the stomach. C, In the erect position the stomach has a more 'J'-shaped configuration.
The left gastric artery may arise from the common hepatic artery or its branches. The most common variant is an origin from the left hepatic artery, when the left gastric artery passes between the peritoneal layers of the superior lesser omentum to reach the lesser curvature of the stomach. Other variants include a common origin with the common hepatic artery. An aberrant left hepatic artery can occasionally arise from the left gastric artery: identification of an aberrant origin may be of importance during surgical mobilization of the upper stomach.
UPDATE Date Added: 13 December 2005
Publication Services, Inc.
Abstract: An anomalous case of the left gastric artery, the splenic artery, and hepato-mesenteric trunk independently arising from the abdominal aorta.
Click on the following link to view the abstract: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract_uids=16119612&query_hl=3 An anomalous case of the left gastric artery, the splenic artery, and hepato-mesenteric trunk independently arising from the abdominal aorta.
Saga T, Hirao T, Kitashima S et al. Kurume Med J 52(1-2):49-52, 2005.
Short gastric arteries
The short gastric arteries are variable in number, commonly between five and seven, and arise from the splenic artery, its divisions, or from the proximal left gastroepiploic artery. They pass between layers of the gastrosplenic ligament to supply the cardiac orifice and gastric fundus, and anastomose with branches of the left gastric and left gastroepiploic arteries. An accessory left gastric artery may arise with these vessels from the distal splenic artery.
Left gastroepiploic artery
The left gastroepiploic artery arises from the splenic artery as its largest branch near the splenic hilum. It runs anteroinferiorly between the layers of the gastrosplenic ligament and into the upper gastrocolic omentum. It lies between the layers of peritoneum close to the greater curvature, running inferiorly to anastomose with the right gastro epiploic artery. It gives off gastric branches to the fundus of the stomach through the gastrosplenic ligament and to the body of the stomach through the gastrocolic omentum. These are necessarily longer than the gastric branches of the right gastroepiploic artery and may be 8-10 cm long. Epiploic (omental) branches arise along the course of the vessel and descend between the layers of the gastrocolic omentum into the greater omentum. A particularly large epiploic branch commonly originates close to the origin of the left gastroepiploic artery, descends in the lateral portion of the greater omentum and provides a large arterial supply to the lateral half of the omentum.
Posterior gastric artery
A distinct posterior gastric artery may occur. When present, it arises from the splenic artery in its middle section posterior to the body of the stomach. It ascends behind the peritoneum of the lesser sac towards the fundus. It reaches the posterior surface of the stomach in the gastrophrenic fold.
Right gastric artery
Figure 71.7 Endoscopic appearance of the stomach: A, cardiac orifice from below; B, body greater curvature; C, body lesser curvature; D, pylorus.
The right gastric artery arises from the hepatic artery as it passes forwards from the posterior wall of the lesser sac into the lower border of the lesser omentum above the first part of the duodenum. The right gastric artery then runs between the peritoneal layers of the lesser omentum just above the medial end of the lesser curvature. It passes superiorly along the lesser curvature, giving off multiple branches onto the anterior and posterior surfaces of the stomach, and anastomoses with the left gastric artery.
The origin of the right gastric artery is often variant. The most common alternative origins are from the common hepatic, left hepatic, gastroduodenal or supraduodenal arteries.
The gastroduodenal artery arises from the common hepatic artery posterior and superior to the first part of the duodenum. It gives origin to the right gastroepiploic and superior pancreaticoduodenal arteries at the lower border of the first part of the duodenum.
Figure 71.8 Arterial supply of the stomach.
Right gastroepiploic artery
The right gastroepiploic artery originates from the gastroduodenal artery behind the first part of the duodenum, anterior to the head of the pancreas. It passes inferiorly towards the midline between the layers of the gastrocolic omentum. It lies inferior to the pylorus and then runs laterally along the greater curvature. It ends by anastomosing with the left gastroepiploic artery. It is adjacent to the pylorus but, more distally, lies c.2 cm from the greater curvature of the stomach. Gastric branches ascend onto the anterior and posterior surfaces of the antrum and lower body of the stomach while epiploic branches descend into the greater omentum. It also contributes to the supply of the inferior aspect of the first part of the duodenum.
Arterial anastomoses of the stomach
There is an anastomosis between the oesophageal arteries originating from the thoracic aorta and the vessels supplying the fundus in the region of the cardiac orifice. At the pyloric orifice the extensive network of vessels supplying the duodenum allows for some anastomosis between vessels of superior mesenteric artery origin and the pyloric vessels. The major named vessels supplying the stomach form extensive arterial anastomoses both on the serosal surface and around the curvatures. The right and left gastroepiploic arteries and the left and right gastric arteries anastomose freely with each other along the greater and lesser curvatures respectively. Anastomoses also form between the short gastric and left gastric arteries in the region of the fundus, and between the right gastric and right gastroepiploic arteries in the region of the antrum. In addition to the extensive serosal anastomoses, networks form within the stomach wall at intramuscular, submucosal and mucosal levels. A true plexus of small arteries and arterioles is present within the submucosa: it supplies the mucosa and shows considerable regional variation both in the gastric wall and in the proximal duodenum. The rich arterial supply to the stomach ensures that the high mucosal blood flow required for physiological functioning is maintained even if one or more vessels become occluded. As a consequence, the stomach exhibits considerable resistance to ischaemia even when multiple arterial supplies are lost.
Figure 71.9 The coeliac axis and its branches demonstrated on: A, digital subtraction angiogram demonstrating a replaced right hepatic artery arising from the origin of the superior mesenteric artery and being filled by a collateral from the left gastric artery. (A, by kind permission from Dr Adam Mitchell, Charing Cross Hospital London; B and C, by kind permission from GE Worldwide Medical Systems.)
The pyloric arteries are rami of the right gastric and right gastroepiploic arteries and pierce the duodenum distal to the sphincter around its entire circumference. They pass through the muscular layer to the submucosa where they divide into two or three rami, which turn back into the pyloric canal beneath the mucosa and run to the end of the pyloric antrum (Fig. 71.10). They supply the entire mucosa of the pyloric canal. Branches of these pyloric submucosal arteries may anastomose close to their origin with the duodenal submucosal arteries. Their terminal rami also anastomose with gastric arteries from the prepyloric antrum. The pyloric sphincter is supplied by the gastric and pyloric arteries via rami that leave their parent vessels in the subserosal and submucosal levels to penetrate the sphincter.
Dieu la Foy lesions
Abnormalities of the intramural vascularity of the stomach are a rare cause of bleeding from the upper gastrointestinal tract. So-called 'Dieu la Foy' lesions commonly occur in the proximal body or fundus. When not actively bleeding, they appear as small, raised, red dots marking the mucosal surface of the proximal body or fundus. They were originally thought to be small arteriovenous malformations of the submucosal plexus. It is now considered that such lesions are caused by a larger than normal penetrating arterial vessel running through the muscular coat of the stomach into the submucosa before branching into the submucosal plexus. Although not a pathological abnormality, the vessel has a greater than normal calibre for arteries at this level. The pulsatile flow, combined with its proximity to the overlying mucosa, may then lead to focal ulceration and rupture of the vessel following minor trauma, leading to profuse intraluminal bleeding.
VEINSThe stomach veins drain ultimately into the portal vein. A rich submucosal and intramural network of veins gives rise to veins that usually accompany the corresponding named arteries. They drain either into the splenic or superior mesenteric veins although some pass directly into the portal vein.
Short gastric veins
Four or five short gastric veins drain the gastric fundus and the upper part of the greater curvature. They drain into the splenic vein or one of its large tributaries.
Left gastroepiploic vein
Figure 71.10 Blood supply of the stomach and the proximal duodenum. A scheme of arterial arrangements at the gastroduodenal junction. Dotted lines indicate sites where the submucous plexus may be non-continuous. Shaded areas represent the muscular layer of the visceral wall. (Redrawn courtesy of C Piasecki, Department of Anatomy, Royal Free Hospital School of Medicine, London and the Journal of Anatomy.)
The left gastroepiploic vein drains both anterior and posterior gastric surfaces and the adjacent greater omentum. It runs superolaterally along the greater curvature, between the layers of the gastrocolic omentum. It receives multiple tributaries from the anterior and posterior surfaces of the body of the stomach and the greater omentum, and drains into the splenic vein within the gastrosplenic ligament.
Right gastroepiploic vein
The right gastroepiploic vein drains the greater omentum, distal body and antrum of the stomach. It passes medially, inferior to the greater curvature, in the upper portion of the gastrocolic omentum. Just proximal to the pyloric constriction it passes posteriorly to drain into the superior mesenteric vein below the neck of the pancreas. It may receive the superior pancreaticoduodenal vein close to its entry into the superior mesenteric vein.
Left gastric vein
The left gastric vein drains the upper body and fundus of the stomach. It ascends along the lesser curvature to the oesophageal opening where it receives several lower oesophageal veins. It then curves posteriorly and medially behind the posterior peritoneal surface of the lesser sac. It drains into the portal vein directly at the level of the upper border of the first part of the duodenum.
Right gastric vein
The right gastric vein is typically small and runs along the medial end of the lesser curvature. It passes under the peritoneum as it is reflected from the posterior aspect of the pylorus and first part of the duodenum onto the posterior wall of the lesser sac. It drains directly into the portal vein at the level of the first part of the duodenum. It receives the prepyloric vein as it ascends anterior to the pylorus at the level of the pyloric opening.
Posterior gastric veins
Distinct posterior gastric veins may occur. When present, they accompany the posterior gastric artery from the middle of the posterior surface of the stomach. They drain into the splenic vein and may occur as multiple small vessels.
Variceal dilatation of the submucosal veins of the stomach may occur in the presence of portal hypertension. The anastomosis between portal and systemic venous circulations occurs around the lower oesophagus and upper stomach. Submucosal veins close to the cardiac orifice may become involved in the pathological flow of blood from the stomach and other upper abdominal viscera into the oesophageal veins. Gastric varices present less commonly in clinical practice than oesophageal varices. Occasionally gastric varices exist without the presence of oesophageal varices. In these circumstances, it may be that the effective 'point of meeting' between portal and systemic venous systems is lower than usual and occurs in the upper stomach rather than the lower oesophagus.
LYMPHATIC DRAINAGEThe stomach has a rich network of lymphatics that connect with lymphatics draining the other visceral organs of the upper abdomen. At the gastro-oesophageal junction the lymphatics are continuous with those draining the lower oesophagus. In the region of the pylorus they are continuous with those draining the duodenum. In the main, they follow the course of the arteries supplying the stomach, however many separate node groups are now recognized (Fig. 71.11). The relationship of separate node groups to the regions of the stomach and the vascular territories supplied is of great importance during resection of the stomach, particularly for malignancy. Pancreatic and hepatic lymphatics play a considerable role in draining areas of the stomach during disease.