Example on livor mortis on JonBenet. She had some streaks of red and white bands on her back at waist level, indicating that whatever she was lying on had moved or her body had.
If an object is protruding into the skin or constricting where the blood flows while livor mortis is taking place (it's a somewhat gradual process, not all at once), it will show up when the livor is finalized.
Those bands of blanching on her back turned out to be from the elastic on the waistband of her thermal leggings. It could be interpreted that she was dragged and the elastic was being pulled down (as if she were dragged by the arms raised over her head and the pants were coming downward) or just that as the fullness of her body was shrinking in death (blood and oxygen no longer coursing through the tissues), the elastic was inching downward.
The red bands would be blood; the white bands, the blanching where the tightening elastic was.
A contusion is a response to a trauma; a hemorrhage can take place on its own for an internal reason. There is often swelling with a contusion, in addition to the darker purple color of the area affected.
Sulci are the valleys or furrows in the brain "wrinkles" and gyri are the peaks. As they fill with fluid, the gyri become fuller and the valleys narrow because the peak "bumps" take up more room. If they swell too much, they reach the brain cap and skull, thus flattening the puffed-up peaks.
Bruising on the temporal lobes' tips indicates "coup" - the word I was trying to think of the other day. Think of it as "bounce." Contre-coup is when the brain is jostled in such a way that it bangs against the *opposite* wall of the skull from the direction the blow came.
Coup indicates the jostling happened. In this case, there was some movement of the brain from side to side, rather than from back to front. It could have even been up and down - the blow could have come from above. I believe the temporal segments that were affected are the slimmest connections, therefore they show coup first, in a slight blow.
JonBenet's temporal contusions were slight, but they were there, more on the right than on the left.
Again, forgive my making up words to describe these; it's difficult for me to relate what I'm picturing.
Fascinating. Wouldn't contra-coup indicate a blow with a stationary object? Just thinking about the physics of it, I would think that a moving object would not cause the brain to recoil against the opposite side of the skull...