If you want to know a lot about the four muscles that make up the rotator cuff then you need to read these three posts

Infraspinatus & Teres Minor – the External Rotators

Supraspinatus & Why You Should Stop Doing the Empty Can Drill!!!

Subscapularis –  the Internal Rotator

If you interested in what I think is needed to care for a healthy throwing arm then check out these two articles

Arm Care – the Rotator Cuff and Beyond

Video’s of the Best Arm Care Exercises