I have a couple questions about my knees out of pure curiosity. On the inside of both my knees, the innermost rounded part when you are sitting down (on my body at least), there are several long thin white lines that look like scar tissue or stretch marks. I've never injured myself there and I am not overweight, what are they? I find it especially odd that they are in the same spot. Also, on the inside of my left knee a few inches below the knee cap, about even with where my shin starts, there is an obvious bump or "notch" if you will, of what feels just like bone. Its hard, doesn't move whatsoever, and has no feeling. What is it? Neither of these things cause me any pain or discomfort and I have had them for at least the past 4 years, I am 18. I am just curious to find out what they are.