1. "Well defined lines of ramification" means that where the pain is located is very clear - not a dull ache over an area, where you couldn't exactly located, but in very obvious lines. "Ramification" means that the possible damage that the pain would indicate was clear - a deep, sharp pain in your chest would mean a heart attack, while a sharp pain in your knee would mean a sever injury and trouble walking. 2. "Flash along" - it would pulsate, becoming suddenly very intense, then go away, then 'flash' again.

"flash along" is the easier one. It simply means "to pulsate through." The "well-defined lines of ramification" part is more difficult. This is not a common phrase. In fact, I've never seen it before, so I'm assuming the author created it for imagery purposes. I'm assuming, also, that you understand "well-defined" and that the "lines of ramification" part is the confusing one. "Ramification" means that there's a negative consequence to something. So, this could mean something as simple as the idea that he was very clearly feeling the consequences of the fall. However, because the author is so metaphorical, I am left wondering if he intended to mean something deeper. If he did, I can't figure out what that might be. In my humble opinion, this phrase is confusing and a bit too obscure. As I read it, I stumbled on that wondering what it meant, and I thought it took away from the beauty of the rest of the well-written piece. But perhaps someone else will have a better explanation of than I do.