A has-been who never was wrote:
I will try and give a serious answer to this question. I am a 62-year old, ex-2:16 marathoner. In my good running years, I had big quads and I had the same thing. To show it, I need only pull my heel to my butt with my hand. (Stretching the quad). Had the same horizontal, three-dimensional lines (bumps).. Someone gave me a reasonable explaination for it. He said that the quad was so big that there were tears or weakness in the sheath surrounding the quad. It was basically bulging out in these weak or torn areas. Now that I am older and weaker with smaller quads, I don't really have it anymore. Pulling my heal to my butt, I can barely still feel it. I hope this helps.
Was that someone a doctor, if not you should be tested for worms, just in case