- Seated or standing
- Shoulder elevated to 90° in the scapular plane
- Forearms fully pronated (thumb UP)
- Examiner instructs the patient to resist downward pressure on the elbow.
Positive Sign / Significance
- Pain, weakness in shoulder = Supraspinatus tendinitis/tear
- The supraspinatus is best isolated with the thumb UP (full can test), rather than with the thumb DOWN (empty can test)
- The empty can test is more likely to cause pain, and therefore may not show true weakness of the supraspinatus (due to a tear).
- The full can test is now thought to be better because of this.