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!