Step 1: Painful arc syndrome, also called impingement or supraspinatus syndrome, is shoulder pain occurring during a specific arc of abduction.
Step 2: The pain is felt between about 60 degrees and 120 degrees of abduction - that is, during mid abduction, when the rotator cuff is compressed under the acromion.
Step 3: It results from supraspinatus tendinitis or minor tears, calcification, subacromial bursitis or a fractured greater tuberosity narrowing the subacromial space.
Step 4: Because pain occurs in the middle arc and not at the start, end, or overhead, the answer is mid abduction.