I think those blood drops were from her nose, as they've landed in a complete line on top of her arm and because liquid runs downwards it's run down both sides of her arm------not a difficult thing to work out really being as her arms were slim. Maybe if she'd had a thicker arm the blood might have just run one way.
Blood coming from the nose is a continual drip-drip motion and landing on the top centre of her arm made the 7 streaks possible, running down either side.