Nope. Not a reference to reggae music.
Not even a reference to putting up preserves in the summer.
I apparently tried to jam my thumb today while running errands. You see, I picked up a new bag of dog food, and had to set it on the counter. The problem was that although it was actually only about 30 pounds (so, really, not all that heavy), it was vacuum packed, so the bag is kind of hard as a rock.
As I set it on the counter, I realized that the UPC was on the bottom, so I did the good customer thing and flipped it over. And, in so doing, whacked my thumb into it.
I should say that I have kind of weird thumbs to begin with. They're not truly double-joined, but they can bend backward at the knuckle to about 90 degrees. (When I was younger and in the habit of trying to freak people out, I could get them to bend to at least 135 degrees, or enough to look like a V, if not a U...)
So, the weird thumb is kind of prone to flipping back, anyway, and then it meets the resistance of the rather hard bag o' food and... yowch.
At least it happened at the end of the day. I only had one other errand to run, then I came home and took three Ibuprofen. Which, along with a pseudofed for my sinuses, has taken the edge off.
No bruising or swelling, at least, but it might make it hard to hitchhike for the next couple of weeks...