Left gastric artery

The left gastric artery is the smallest of the three major branches of the celiac trunk, which arises from the abdominal aorta. It primarily supplies blood to the stomach and the lower part of the esophagus.

Location

The left gastric artery originates from the celiac trunk in the upper abdomen and ascends towards the lesser curvature of the stomach. It runs along the lesser curvature, providing blood to the stomach’s upper part and the adjacent lower esophagus. As it ascends, it gives off esophageal branches that supply the lower part of the esophagus. The left gastric artery also forms an important anastomosis with the right gastric artery along the lesser curvature of the stomach, ensuring continuous blood flow in this region. It lies within the layers of the lesser omentum, connecting the stomach to the liver.

Structure and Anatomy

Origin

The left gastric artery is one of the three main branches of the celiac trunk, which arises from the abdominal aorta at the level of the twelfth thoracic vertebra (T12). The celiac trunk gives rise to three key branches: the left gastric artery, the splenic artery, and the common hepatic artery. Of these, the left gastric artery is typically the smallest and the first to branch off.

Course

After originating from the celiac trunk, the left gastric artery ascends upward and to the left. It initially moves toward the esophageal hiatus, an opening in the diaphragm through which the esophagus passes. Here, the artery gives off small esophageal branches that supply the lower portion of the esophagus.

After ascending, the left gastric artery curves downward and travels along the lesser curvature of the stomach, running within the layers of the lesser omentum, which connects the stomach to the liver. As it travels along the lesser curvature, the artery supplies blood to the stomach’s lesser curvature and the adjacent anterior and posterior surfaces of the stomach.

Branches

The left gastric artery gives rise to several smaller branches that supply both the stomach and the esophagus:

• Esophageal Branches: As the left gastric artery ascends toward the esophageal hiatus, it gives off small branches that ascend to supply the lower part of the esophagus. These branches form anastomoses with branches of the inferior phrenic artery and other esophageal arteries, ensuring a continuous blood supply to the distal esophagus.
• Gastric Branches: As the artery descends along the lesser curvature of the stomach, it gives off several small branches that supply the upper portion of the stomach, particularly along the lesser curvature. These branches penetrate the stomach wall to nourish the muscular and mucosal layers.

Anastomosis

A key feature of the left gastric artery is its anastomosis with the right gastric artery along the lesser curvature of the stomach. The right gastric artery typically arises from the common hepatic artery and runs along the lower portion of the lesser curvature, where it meets the left gastric artery. This anastomosis ensures a continuous and redundant blood supply to the lesser curvature and the nearby stomach tissue.

This anastomotic network provides a safeguard against ischemia in the stomach by maintaining blood flow even if one artery becomes compromised. It is particularly important during surgical procedures, such as gastrectomy, where preserving blood flow to the stomach is critical.

Relations

• Anteriorly: The left gastric artery is related to the anterior surface of the stomach, particularly near the lesser curvature, and is covered by the peritoneum as it runs within the lesser omentum.
• Posteriorly: Behind the left gastric artery are the esophagus and left crus of the diaphragm, with the artery ascending toward the esophageal hiatus. It is also posteriorly related to the splenic artery and parts of the pancreas as it courses near the lesser curvature.
• Superiorly: The left gastric artery’s uppermost branches are related to the diaphragm and the esophagus, providing blood to the lower esophagus.
• Inferiorly: Inferior to the left gastric artery lies the stomach, particularly the upper body and fundus regions, which receive blood from its branches.

Length and Diameter

The left gastric artery is relatively short, with its length determined by the distance from its origin at the celiac trunk to its terminal anastomosis with the right gastric artery. Its diameter is smaller compared to the splenic and common hepatic arteries, reflecting its role in supplying a smaller portion of the upper stomach and esophagus.

Termination

The left gastric artery terminates by anastomosing with the right gastric artery along the middle of the lesser curvature of the stomach. As it approaches this point, it sends out small branches to supply both the anterior and posterior surfaces of the stomach. The artery’s smaller esophageal branches terminate by forming connections with other esophageal arteries near the esophageal hiatus.

Anatomical Variations

Anatomical variations in the left gastric artery are relatively uncommon but can occur. Some notable variations include:

• Aberrant Origin: In rare cases, the left gastric artery may arise directly from the abdominal aorta rather than the celiac trunk. This variation is important for surgeons to recognize, as it can affect the blood supply to the stomach and esophagus.
• Additional Branches: The number of esophageal and gastric branches given off by the left gastric artery can vary between individuals. In some cases, the artery may give rise to additional small arteries that supply nearby tissues.
• Different Anastomotic Patterns: The point at which the left gastric artery anastomoses with the right gastric artery may vary in its exact location along the lesser curvature.

Blood Supply Regions

The left gastric artery supplies blood to several important regions, including:

• The lesser curvature of the stomach, particularly the upper portion.
• The lower esophagus, including the esophagogastric junction, through its esophageal branches.
• The stomach’s anterior and posterior surfaces, primarily along the upper body and fundus, via small gastric branches.

Function

The left gastric artery plays a crucial role in supplying oxygenated blood to the stomach and lower esophagus. Its branches ensure that the gastric mucosa and esophageal tissues are properly nourished and can perform their functions in digestion and protection. Below is a detailed description of its functions based on the regions it supplies.

Blood Supply to the Lesser Curvature of the Stomach

One of the primary functions of the left gastric artery is to supply blood to the lesser curvature of the stomach. This region is essential for the digestive process, and the blood supplied by the left gastric artery supports several important functions:

• Nourishment of the Gastric Mucosa: The lesser curvature is lined with mucosal cells that secrete mucus, bicarbonate, and digestive enzymes. The blood supplied by the left gastric artery delivers the oxygen and nutrients necessary to sustain these cells and their functions, helping to protect the stomach from the acidic environment and facilitating the breakdown of food.
• Support for Gastric Acid Secretion: The left gastric artery supplies blood to the parietal cells in the stomach, which are responsible for secreting hydrochloric acid (HCl). This acid is critical for digestion, as it breaks down food and activates enzymes like pepsin. The artery’s blood flow ensures that the cells involved in acid production have the energy and nutrients they need to function properly.
• Maintenance of Peristalsis: The smooth muscle along the lesser curvature is responsible for peristaltic contractions that mix and propel food toward the pylorus and duodenum. The left gastric artery’s blood supply supports these muscle layers, providing the oxygen necessary for muscle contraction and effective movement of food through the stomach.

Blood Supply to the Lower Esophagus

The left gastric artery also supplies the lower part of the esophagus through its esophageal branches. This function is critical for maintaining the health and functionality of the esophagogastric junction and the lower esophagus:

• Protection of the Esophageal Mucosa: The esophagus is lined with a mucosal layer that helps protect it from damage caused by acid reflux. The esophageal branches of the left gastric artery supply blood to the lower esophageal mucosa, ensuring that the cells responsible for secreting protective mucus are well-nourished and functional.
• Prevention of Acid Erosion: The lower esophagus is vulnerable to acid exposure due to its proximity to the stomach, especially in conditions like gastroesophageal reflux disease (GERD). The blood flow provided by the left gastric artery helps maintain the health of the esophageal tissues, reducing the risk of erosion or ulceration caused by stomach acid.
• Support for the Esophagogastric Junction: The left gastric artery also helps maintain the blood supply to the esophagogastric junction, the region where the esophagus meets the stomach. This area is vital for preventing reflux of gastric contents into the esophagus, as the lower esophageal sphincter relies on proper muscle tone and integrity, which are supported by the artery’s blood supply.

Oxygen and Nutrient Delivery

Like all arteries, the left gastric artery’s primary role is to deliver oxygen and nutrients to the tissues it supplies. This is particularly important for the rapidly renewing cells of the stomach and esophagus, which are constantly exposed to mechanical and chemical stresses:

• Cellular Metabolism: The cells in the stomach’s mucosal lining and the esophageal wall require a steady supply of oxygen to generate energy through cellular respiration. The blood provided by the left gastric artery supports this metabolic activity, allowing the cells to perform their digestive and protective functions effectively.
• Tissue Repair and Regeneration: The stomach and esophagus undergo continuous wear and tear due to the mechanical action of digestion and exposure to stomach acid. The blood flow from the left gastric artery supports the repair and regeneration of these tissues, ensuring that they can maintain their integrity and protect against damage.

Role in Anastomotic Circulation

The left gastric artery forms an important anastomosis (vascular connection) with the right gastric artery along the lesser curvature of the stomach. This anastomotic network provides several key functions:

• Ensuring Redundant Blood Supply: The anastomosis between the left and right gastric arteries ensures that the stomach’s lesser curvature receives a continuous blood supply from two sources. This redundancy is crucial in maintaining the health of the gastric tissues, especially if one artery becomes compromised due to injury, blockage, or surgical ligation.
• Support During Surgical Procedures: In surgeries involving the stomach, such as partial gastrectomy, the anastomotic network between the left and right gastric arteries helps preserve blood flow to the remaining parts of the stomach. This ensures that the stomach continues to receive adequate blood supply, reducing the risk of ischemic complications after surgery.

Contribution to Digestive Function

The left gastric artery supports the digestive function of the stomach by providing the necessary blood flow for the production of digestive enzymes, mucus, and acid:

• Acid and Enzyme Production: The blood supplied by the left gastric artery ensures that the gastric glands, including the parietal cells and chief cells, have the oxygen and nutrients they need to secrete acid and digestive enzymes. These secretions are essential for breaking down food into smaller molecules that can be absorbed in the intestines.
• Protection of the Stomach Lining: The gastric mucosa produces mucus and bicarbonate to protect the stomach’s lining from the corrosive effects of gastric acid. The blood flow provided by the left gastric artery supports the cells responsible for producing this protective barrier, helping to prevent ulcers and other forms of gastric damage.

Clinical Significance

The left gastric artery is clinically significant because of its role in supplying blood to the stomach and lower esophagus. It is commonly involved in upper gastrointestinal bleeding, particularly in cases of gastric ulcers or esophageal varices. Erosion of the artery by ulcers along the lesser curvature of the stomach can result in life-threatening hemorrhage, making it a critical structure during endoscopic and surgical interventions.

Additionally, the left gastric artery’s proximity to the esophagus makes it important during surgeries for esophageal cancer or hiatal hernia repair, where its branches must be carefully managed. It is also frequently involved in procedures such as gastrectomy (partial or total removal of the stomach) and gastric bypass surgery, where preserving or managing its blood supply is essential to prevent complications like ischemia or necrosis of gastric tissues. Its involvement in the anastomotic network with the right gastric artery helps ensure continuous blood supply to the lesser curvature of the stomach during such procedures.