Anatomical and physiological background

The stomach is located in the left upper part of the abdomen immediately below the diaphragm. The shape of the organ is greatly modified by changes within itself and in the surrounding viscera such that no one form can be described as typical. The chief configurations are determined by the amount of the stomach contents, the stage of the digestive process, the degree of development of the gastric musculature and the condition of the adjacent loops of the small and large intestines. The stomach is more or less concave on its right side, convex on its left. The concave border is called the lesser curvature; the convex border, the greater curvature. The region that connects the lower oesophagus with the upper part of the stomach is called the cardia. The uppermost adjacent part to it is the fundus. The fundus adapts to the varying volume of ingested food and it frequently contains a gas bubble, especially after a meal. The largest part of the stomach is known simply as the body. The antrum, the lowermost part of the stomach, is usually funnel-shaped, with its narrow end connecting with the pyloric region. The latter empties into the duodenum – the upper division of the small intestine. The pyloric portion of the stomach tends to curve to the right and slightly upwards and backwards and thus gives the stomach its J-shaped appearance (Fig. 7.1).