The CA, also known as the celiac trunk, is the first unpaired branch of the abdominal aorta. It is only 1–2 cm in length and branches from the aorta anterior to the level of T12, slightly below the aortic hiatus of the diaphragm. The gastric arteries originate from the CA, which has three main divisions: the LGA, CHA, and SpA (Figs. 5.10, 5.11, and 5.12).

Adachi’s classification of the CA describes six variant subtypes based on the analysis of 252 cases [18].

In most cases, the LGA stems from the CA. In 2.5–7.5 % of cases, it instead arises directly from the right posterior aspect of the abdominal aorta above the origin of the CA. After issuing from the CA, the LGA clings to the posterior abdominal wall and runs toward the upper left side along the deep parietal peritoneum of the omental bursa to the dorsal side of the cardia. Then, it turns right and passes along the lesser curvature of the stomach between the layers of the lesser omentum to join with the right gastric artery (RGA) (Fig. 5.24). In approximately 1.0–23.0 % of cases, an accessory left gastric artery (ALGA) issues from the left or proper hepatic artery (LHA or PHA) (Figs. 5.25, 5.26, and 5.27) and runs along the same course to supply the lesser curvature of the stomach. In addition, in some patients, an accessory LHA (ALHA) originates from the LGA, branching off from this artery at its highest point or at the turning point before it runs down toward the lesser curvature of the stomach. The extrahepatic part of the ALHA is short. Within the HGL, the ALHA extends toward the right or upper right in a straight or slightly tortuous course to enter the hepatic parenchyma through the left sagittal groove, anterior to the caudate lobe. It extends to the left, dividing into several segmental or subsegmental branches to supply the left lateral lobe of the liver. Its diameter is equivalent to the level 2 and 3 hepatic artery.

The incidence of an ALHA has been reported to be 5.0–11.5 %. Of our 1,173 patients who underwent radical gastrectomy for gastric cancer, 135 (11.5 %) had an ALHA [19] (Figs. 5.28 and 5.29).

The CHA, which arises from the celiac trunk, passes to the right side and runs forward along the upper border of the pancreatic head. It then enters the HDL and gives off the gastroduodenal artery (GDA) and PHA above the duodenum (Figs. 5.30 and 5.31).

Less variation is associated with the CHA, but occasionally it may be absent (range, 1.4–6.2 % of cases). When the CHA doesn’t arise from the CA as usual, it can be regard as absence according to Gray’s Anatomy [20]. The CHA was found to be absent in 38 cases (1.8 %) based on the analysis of 2,170 patients with gastric cancer by our center. The anatomy of absence of CHA was classified into six types according to the anatomy of the replaced CHA (RCHA) as follows:

The GDA stems from the CHA. It descends behind the first part of the duodenum. Upon reaching the lower border of the pylorus, it splits into right gastroepiploic and anterior superior pancreaticoduodenal arteries (Figs. 5.55 and 5.56).

The PHA arises directly from the CHA and runs to the upper right within the HDL. It runs to the left and anterior of the PV and on the left side of the common bile duct in the HDL. Then, it terminates by bifurcating into the right and left hepatic arteries near the porta hepatis, sending small branches to the middle of the common bile duct along the way. The PHA is separated from the CHA by the bifurcation of the GDA, called the T-shaped intersection. The PHA is distal to the division, while the CHA is proximal to it (Figs. 5.57 and 5.58).

The RGA most frequently arises from the PHA above the first part of the duodenum. It runs upward between the two layers of the HDL to the pylorus. It then passes from right to left along the lesser curvature of the stomach, supplying both of its surfaces with branches, and joins with the LGA (Figs. 5.59 and 5.60).

According to Adachi’s study of the RGA in 191 patients, the origin of this artery varies considerably [18]: The RGA originated from the PHA in 93 patients (48.7 %) (Figs. 5.61 and 5.62); LHA in 38 patients (19.9 %) (Figs. 5.63 and 5.64); GDA in 28 patients (14.7 %) (Figs. 5.65 and 5.66); near the T-shaped intersection of the CHA, PHA, and GDA in 17 patients (8.9 %) (Figs. 5.67 and 5.68); and CHA in 3 patients (1.6 %) (Figs. 5.69 and 5.70).

The SpA branches from the CA to supply blood to the spleen. It meanders toward the left along the upper border of the pancreas and gives off branches to the stomach and pancreas before reaching the spleen (see the Chap. 6.​2 for details).

The LGV (or gastric coronary vein) receives venous blood from the branches corresponding to the area of the LGA. It originates from small venous branches coming from the anterior and posterior walls of the stomach and accompanies the artery of the same name to run along the gastric lesser curvature between the two layers of the lesser omentum. It receives the venous blood of branches from the anterior and posterior sides of the gastric lesser curvature, the cardiac region, and the lower half of the esophagus as well as drains one to two small vessels in the posterior abdominal wall. It ascends to the cardia and receives the esophageal vein from the lower half of the esophagus and then turns right. The drainage of the LGV has three possible patterns: the LGV ends in the PV (approximately 60.0 % of cases), it drains into the splenic vein (SpV) (approximately 30.0 %), or it drains into the splenoportal confluence (approximately 10.0 %) (Figs. 5.71, 5.72, 5.73, 5.74, and 5.75). The course of the LGV can also vary. In an analysis of 1,325 patients who underwent laparoscopic radical gastrectomy for gastric cancer by our center [21], we found that the LGV passed to the ventral side of the SpA and the CHA in 56.1 % of cases and to the dorsal side of the CHA in 41.5 % of cases. In approximately 1.6 % of cases, the coronary vein independently passes through the GHL and drains into the PV at the porta hepatis without accompanying the similarly named artery. It is called the intrahepatic LGV in this situation (Figs. 5.76 and 5.77). In about 0.5 % of cases, the LGV is absent, and the right gastric vein (RGV) is enlarged in compensation (Figs. 5.78 and 5.79). Moreover, we have described a rare anatomical variant of the LGV (Fig. 5.80), in which it descends along the GPF, runs across the dorsal side of the SpA, and drains into the SpV [22]. This previously undescribed anatomical variant had an incidence of 0.3 % (six cases) in our study. The mean diameter and length of this variant LGV were 5.10 ± 0.40 mm and 37.40 ± 5.19 mm, respectively, and the mean distance from the end of the LGV to the splenoportal confluence was 13.05 ± 0.86 mm. The closer the LGV and LGA were to the root, the greater the distance between them, with a mean difference of 13.85 ± 1.02 mm between the end of the LGV and the root of the LGA. In addition, there may be double LGVs (Fig. 5.81).