Stomach "mouth". The words "gastro-" and "gastric" (meaning related to the stomach) are both derived from the Greek word "gaster" (, meaning "belly"). Although the precise shape and size of the stomach varies widely among different vertebrates, the relative positions of the oesophageal and duodenal openings remain relatively constant. As a result, the organ always curves somewhat to the left before curving back to meet the pyloric sphincter. However, lampreys, hagfishes, chimaeras, lungfishes, and some teleost fish have no stomach at all, with the oesophagus opening directly into the anus. These animals all consume diets that either require little storage of
Curvatures of the stomach pyloric than its cardiac end is a well-marked notch, the "incisura angularis", which varies somewhat in position with the state of distension of the viscus; it serves to separate the stomach into a right and a left portion. The lesser curvature gives attachment to the two layers of the hepatogastric ligament, and between these two layers are the left gastric artery and the right gastric branch of the hepatic artery. Curvatures of the stomach The curvatures of the stomach refer to the greater and lesser curvatures. The greater curvature of the stomach is four or five times as long as