This patient most likely has appendicitis, given the migration of his pain from the periumbilical region to the left lower quadrant. The presence of a positive psoas sign also points to a diagnosis of appendicitis.
Check our archives to test your knowledge in other clinical signs:
If you do not already have Acrobat Reader, simply click on the icon below, scroll down to the "Get the Free Acrobat Reader" heading and follow the instructions to install the program. Acrobat enables you to convert any document into an Adobe Portable Document Format (PDF) file for easy viewing.