This document discusses perforated peptic ulcers. It first covers the surgical anatomy and blood supply of the stomach and duodenum. It then discusses the epidemiology, pathophysiology, risk factors, presentation, diagnosis, and treatment of perforated peptic ulcers. Key points include that perforations are more common in duodenal versus gastric ulcers and have a higher mortality rate for gastric ulcers. Risk factors include H. pylori infection, NSAID use, smoking, and Zollinger-Ellison syndrome. Patients typically present with sudden severe abdominal pain. Diagnosis involves upright chest x-rays showing free air. Treatment is surgical repair of the perforation.