Recognising Bowel Obstruction

Key points

• • Small bowel: central loops, valvulae conniventes crossing the full width, diameter over 3 cm.
• • Large bowel: peripheral loops, haustra that do not cross fully, diameter over 6 cm (9 cm at the caecum).
• • Look for a sentinel loop, absent distal gas, and free air suggesting perforation.
• • Correlate with vomiting, distension, pain and absolute constipation.