What is the purpose of the full can test?

• A. To assess supraspinatus strength with reduced impingement position.
• B. To measure infraspinatus flexibility.
• C. To evaluate pectoralis major strength during abduction.
• D. To test subscapularis endurance.

Answer: (A)

The full can test is about isolating supraspinatus function while reducing subacromial impingement. In this position, the arm is raised about 90 degrees in the scapular plane with the thumb pointing upward, then the patient resists downward pressure. This setup allows the supraspinatus to contract against resistance without being overly compressed under the acromion, so a strong, painless contraction supports normal supraspinatus function. If weakness or pain occurs, it points to supraspinatus tendinopathy or tear. The other options don’t fit because they target different structures or properties: infraspinatus flexibility is about external rotation range, pectoralis major strength isn’t tested in this abduction position, and subscapularis endurance is assessed with other maneuvers like the lift-off.