A posteriorly perforating ulcer in the pyloric antrum of the stomach is most likely to produce initial localized peritonitis or abscess formation in the following
"The posterior surface of the stomach is related to structures forming the stomach bed, all of which are separated from the stomach by the cavity of the lesser sac." Thus an ulcer on the posterior wall of the stomach would perforate into the lesser sac. Also, remember Most perforated ulcers are located on the anterior wall. The moality rate for a perforated gastric ulcer is higher than that for duodenal ulcer. This is generally due to the gastric ulcer patients' more advanced age, increased medical comorbidities, delay in seeking medical attention, and the larger size of gastric ulcers. Ref : CSDT 13/e p498
Omental bursa (lesser sac)
Greater sac
Right subphrenic space
Hepato renal space (pouch of Morison)
G.I.T