This might be the wrong place for this question, so if it is, I apologize in advance.
There's this muscle, I think, that everyone has (other than a brain) located kinda between the hip bone and the edge of the oblique (or ab... I don't know). It's the one that can lead you to have something of a V-shaped upper body since it's the bottom part of the "V". Does anyone know the name of this muscle and or how to train it? Am I making sense?