Have a patient with an acute shoulder injury? Are you suspecting a rotator cuff injury? Here is a simple way to isolate which part of the rotator cuff is injured:

Is the tenderness over the deltoid or are they complaining of deltoid pain? Then the rotator cuff is likely injured.

Pain on abduction = supraspinatus injury

Pain with external rotation = infraspinatus injury

Positive lift off or belly test = subscapularis injury

These patients should be put in a sling and referred to ortho as soon as possible. Keep it simple!