Two summers ago, within about a 3 week period, we had 3 high school kids who came to us with medial elbow pain and numbness and tingling into their pinkie and ring fingers.
Any time a pitcher complains of pain on the inside of the elbow, you worry about damage to the UCL -- the dreaded Tommy John surgery. But sometimes it's not the Tommy John ligament at all.
Here is a rudimentary field test to see if you might have damage to the UCL.
It's called "The milking test."