When perforation of the duodenum occurs outside of the peritoneum it can easily be overlooked, with serious or fatal sequelae. Sharp complaint is often lacking and physical signs may be absent or equivocal. Keith and Burch11 have expressed the opinion that 30% of retroperitoneal ruptures are missed even at operation; hence, the problem is worthy of review. The following case report will serve to illustrate some of the considerations involved. Report of Case The patient was admitted to the Cumberland Hospital on Oct. 28, 1958. He was 51 years old, a bookkeeper, employed in a bank. His health was good until 2 weeks before admission, when he slipped in the bath tub and sustained injuries to the back. The interscapular area and the upper lumbar region were particularly hurt, and areas of scuffing and abrasions were still visible in these regions on admission. During his evening meal 2 days