The Characteristics of Bruising
I have a character who is beaten up. How long does it take for the bruising to show?
I envision her having a black eye, a busted lip, a broken arm and perhaps a broken rib or two. I think her arm will have broken as a result of being slammed against the edge of a brick wall, and I assume there will be a major bruise at the point of impact. I want to describe the state of her arm when the police examine it about 1 1/2 – 2 hours after the fact.
Bruising is blood under the skin. That won’t necessarily happen from a broken limb, depending on the mechanism of the break. She would have a road rash type picture from the roughness of the brick wall (though long sleeves might minimize that), and may develop a bruise from that crush, though 2h is a little quick. The appearance of the arm itself would depend again on how exactly you imagine her breaking it. It can look normal, or have a lump, or best might be for it to have an obvious deformity, a bend where there shouldn’t be one. That’s called a “displaced fracture.” If you want to get gory you could have a piece of bone sticking out of the skin, that’s an OPEN fracture and would bleed. Though by 1.5-2h the bleeding should be stopped.
A bone will only break if there are forces opposite to its length, like slamming it against the corner of a brick wall so part of it wraps around the corner, if you know what I mean. Or twisting it. Just slamming someone against a wall wouldn’t break it, unless they had their arms out to break the fall maybe.
Broken ribs CAN bruise, since they’re so close to the skin, assuming your victim isn’t obese, but again it’s not that quick. As an aside, depending on the mechanism of breaking a rib, a portion of it could poke into the lung and cause a “pneumothorax” (air in the chest, but not in the lung). That causes chest pain, breathing difficulty, and can be a major emergency, or not, depending on what you want to happen with your poor soul.