UGME INSTAGRAM CASES
- Answers -
Findings: Football sign (dotted lines), Falciform ligament sign (arrows), Rigler’s sign (arrowheads) Explanation: When supine, free gas sits under anterior abdominal wall, resulting in a football shaped lucency (football sign) and outlining of the falciform ligament. Rigler’s sign is seen when free air abuts the outer wall of bowel (thus, wall is well defined due to air on both sides of wall). This is a good example of the first two signs, and a decent example of Rigler’s sign.
Diagnosis: Free intraperitoneal gas (arrows) Explanation: Keep it simple – air rises. Where you look for free gas depends on patient position – when upright, look under the diaphragms. Free air in the acute setting suggests perforated viscus (i.e. stomach, cecum). However, think of other possible causes of free air before rushing the patient to the operating room (i.e. recent surgery, peritoneal dialysis patient)! For more on abdominal plain films, go to navigatingradiology.com.
Findings: Dilated loops of large bowel. Multiple air fluid levels at different levels. Explanation: The key is to be able to differentiate large and small bowel. Large bowel has haustra (sacculations) and non-circumferential folds. Large bowel is considered enlarged when it measures > 6 cm (or 9 cm for cecum). For more on abdominal plain films, go to navigatingradiology.com medical student section and watch the short video on abdominal xray essentials!
Findings: Dilated loops of small bowel. Multiple differential air fluid levels. Explanation: Dilated small bowel is best identified on supine films (patient lying flat). Small bowel is dilated if > 3 cm. Look for air fluid levels on upright films – the key is having air fluid levels at different heights. Learn what small bowel looks like vs. large bowel. Small bowel has circular folds (plicae circulares) that are circumferential. Watch our short video on Abdo Xray to learn the essentials!