Appendix ultrasound: a positive scan helps

Answer a. An inflamed appendix is wider than 6 mm, does not compress and ends blindly. A compressible tube under 6 mm is a normal appendix. Peristalsis belongs to small bowel. Not seeing the appendix is non-diagnostic, not negative.

Answer c. Slow, steady pressure moves gas-filled bowel out of the way and brings the appendix closer to the probe. Normal bowel collapses. An inflamed appendix does not. Sudden pressure hurts and makes the patient tense the abdomen.

Answer d. Gas, depth, body habitus and a retrocaecal position hide the appendix. Not seeing it does not exclude appendicitis. Record the limits of the scan and follow your local imaging pathway.

Answer c. An appendicolith is a calcified deposit which blocks the appendix. Like a gallstone, it is bright with a shadow behind it. Its presence supports appendicitis and is associated with complicated disease.

Answer c. Asking the patient to point to the most tender spot often leads you straight to the appendix. The caecum and terminal ileum are the landmarks, because the appendix arises from the caecum below the ileocaecal junction.