Blood loss is a likely candidate. If the cut was not big enough for bleeding out to occur, then infection could lead to death.
If you can grab a bone and twist it easily in the meat, then your pork ribs should be done.
The abdomen is an anatomical area that is bounded by the lower margin of the ribs is he pelvic bone.
Lower back area check out link below
The area below the ribs is usually called the abdomen. It may also be the flank or upper quadrant.
break your bottom ribs and have a go!
no i isnt
At the back of the lamb...near its ribs...
The groin
The flank is the lower area of the torso located between the ribs and the hips. It is a fleshy area on the side of the body.
Tharaxus Cage
http://ask.metafilter.com/27259/How-much-meat-is-there-on-a-cow
Every pair of ribs has a distinct shape. An expert could easily tell which one was which. Those near the heart also have the distinction of connecting to the sterum (breast bone).