What is the primary purpose of the empty can test?

What is the primary purpose of the empty can test?

• A. To assess subscapularis strength during internal rotation.
• B. To evaluate deltoid strength during abduction.
• C. To assess supraspinatus contribution to shoulder abduction.
• D. To measure overall shoulder stability.

Answer: (C)

The empty can test is designed to isolate and evaluate the supraspinatus as it contributes to initiating shoulder abduction. With the arm raised to about 90 degrees in the scapular plane and the palm facing downward (internal rotation), the examiner asks for upward resistance. If the supraspinatus is healthy, the person can resist the downward force; weakness or marked pain suggests supraspinatus pathology such as a tear or tendinopathy, which impairs the muscle’s role in lifting the arm. This position helps minimize deltoid dominance, so the test more specifically probes the supraspinatus rather than general shoulder strength. It’s not a measure of subscapularis function or overall shoulder stability, which are assessed by other maneuvers.

The empty can test is designed to isolate and evaluate the supraspinatus as it contributes to initiating shoulder abduction. With the arm raised to about 90 degrees in the scapular plane and the palm facing downward (internal rotation), the examiner asks for upward resistance. If the supraspinatus is healthy, the person can resist the downward force; weakness or marked pain suggests supraspinatus pathology such as a tear or tendinopathy, which impairs the muscle’s role in lifting the arm. This position helps minimize deltoid dominance, so the test more specifically probes the supraspinatus rather than general shoulder strength. It’s not a measure of subscapularis function or overall shoulder stability, which are assessed by other maneuvers.