The most common gastric diverticulum is the true diverticulum which contains muscularis propria, and occurs just below the esophagogastric junction on the posterior aspect of the lesser curvature. Usually they are not larger than 3 or 4 cm and are rarely symptomatic. During an upper GI examination barium tends to flow across the entrance of the diverticulum, thus filling it with barium. However, food rarely collects within it. Other rare forms of gastric diverticulum are the intra-mural and the intra-mucosal types.