A 45-year-old amateur swimmer reports right shoulder pain during overhead activity. Passive abduction reproduces pain only between 60 and 120 degrees, with comfort below and above this range. Resisted abduction with the arm internally rotated and forward flexed (empty can test) is painful and weak. The tendon responsible for this 'painful arc' is:

• A Infraspinatus
• B Supraspinatus ✓
• C Subscapularis
• D Long head of biceps

Explanation

Pain confined to the arc between 60 and 120 degrees of abduction is the classic sign of subacromial impingement of the supraspinatus tendon as it passes beneath the coracoacromial arch; above 120 degrees the tendon clears the arch and pain eases. The empty can (Jobe) test isolates the supraspinatus. Infraspinatus pathology presents with weakness of resisted external rotation, subscapularis with a positive lift-off test, and long head of biceps with anterior groove tenderness on Yergason and Speed tests rather than a true arc pattern.

Reference: Apley's System of Orthopaedics and Fractures, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.