Originally Posted by
Enthalpic
They can happen even with normal clotting function. I suffered a large one on my butt a few years back, it had to be drained by a surgeon a couple times.
If the nature of the impact causes a large sheering force on the skin it can “deglove” or separate the skin from the underlying tissue. The separation creates a pocket which will fill with blood. With most blunt impacts no pocket forms which leaves little place for blood to accumulate.
Yup; happened to me once too. I crashed and landed my full body weight on my hip. That was five years ago and I still don't have feeling on that part of my skin. But usually it takes a pretty big hit to get a hemotoma like that. That picture of the guy's hand is just wrong.
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