What radiographic pattern is typical of small bowel obstruction on plain radiographs?

What radiographic pattern is typical of small bowel obstruction on plain radiographs?

• A. Free air under the diaphragm
• B. Thumbprinting
• C. Dilated loops with multiple air-fluid levels
• D. Calcifications

Answer: (C)

Small bowel obstruction on a plain radiograph shows distended loops of small bowel with air-fluid levels. This pattern arises because a blockage prevents normal passage of contents, causing gas and fluid to accumulate proximal to the obstruction. On an upright film, gravity creates layering, so you see multiple air-fluid levels at different heights, which is a classic sign of mechanical obstruction. Free air under the diaphragm would point to perforation, not an obstruction pattern. Thumbprinting reflects mucosal edema or inflammation, not the typical obstructive gas pattern. Calcifications can indicate other conditions and do not describe the SBO appearance.

Small bowel obstruction on a plain radiograph shows distended loops of small bowel with air-fluid levels. This pattern arises because a blockage prevents normal passage of contents, causing gas and fluid to accumulate proximal to the obstruction. On an upright film, gravity creates layering, so you see multiple air-fluid levels at different heights, which is a classic sign of mechanical obstruction. Free air under the diaphragm would point to perforation, not an obstruction pattern. Thumbprinting reflects mucosal edema or inflammation, not the typical obstructive gas pattern. Calcifications can indicate other conditions and do not describe the SBO appearance.