Whether due to differential growth or actual physical movement, the stomach can be regarded as rotating around the longitudinal and the sagittal axes. The "rotation" around the longitudinal axis starts with the formation of the pneumato-enteric recess on the right side of the dorsal mesogastrium. The recess extends progressively leftwards. The omental bursa (Lesser omentum, greater omentum, and omental bursa) develops from the portion of the recess under the diaphragm. At the same time, in the right hypochondrium, the liver undergoes rapid asymmetrical growth. Due to these two processes the dorsal curvature of the stomach curves to the left, the ventral curvature to the right. The accompanying nerves also become dislocated: the left vagal trunk is found ventrally and the right is found dorsally.
The "rotation" around the sagittal axis can be described as follows: the posterior wall of the stomach grows more quickly than the anterior wall, leading to an evagination that initially is more marked in a dorsal direction and, because of the longitudinal rotation, leftwards. This creates the greater curvature. The position of the stomach changes in relation to the back as the stomach moves downward (descensus of the stomach). It lies between C7 and Th4 at S14, between Th6 and Th11 at S17, and between Th11 and L3 at S20. The downward movement is more pronounced in the area of the future cardia than in that of the developing pylorus, leading to the stomach becoming positioned almost horizontally.