Presentation
Acute onset abdominal pain.
Patient Data

Free air underneath the right diaphragm delineating the right diaphragm and liver margins.
There is also air underneath the central tendon of the diaphragm.
The visualised upper abdomen shows distended bowel loops.
Case Discussion
The presence of crescent lucency underneath the diaphragm is in keeping with pneumoperitoneum with limited differential diagnosis. There is also air underneath the central tendon of the diaphragm, which is similar to the cupola sign (seen on a supine radiograph) 1.
Pneumoperitoneum can be an ominous sign, in this case, it was due to bowel infarction and perforation.