Belly ache and Rigler’s Sign

Labs and Lytes 024

Author: Chris Sia
Reviewers: Sarah Yong and Chris Nickson

A middle-aged gentleman presents with abdominal pain and nausea.



Q1. Describe the x-ray findings?

This is an AP supine abdominal x-ray.

Key findings include:

  • Distended loops of small (5cm) and large (7.5cm) bowel
  • Rigler’s sign is positive, suggesting intra-peritoneal free gas (red arrow)
  • Nasojejunal tube in situ (yellow arrow)
  • Contrast present in the colon and rectum from previous imaging (orange arrow)

Click to enlarge

Click to enlarge

Q2. What is Rigler’s sign?

Riglers sign (aka double-wall sign) is present when both sides of a bowel wall can be visualised, due to delineation by air on either side. It is a good indication of free intraperitoneal gas.

However, the sensitivity for detecting perforation on AXR is low and is best confirmed as subdiaphragmatic air on erect CXR or with a CT scan.

In this case the intraperitoneal gas was the result of a gastric perforation from anastamotic breakdown complicating a prior partial gastrectomy.

Q3. What is the size of normal small bowel, colon and caecum?

Apply the 3-6-9 rule:

  • Small bowel < 3 cm
  • Colon <6cm
  • Caecum <9cm

Small bowel has a central location with valvulae conniventes visible. Large bowel is peripheral with haustra visible.


References and links

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