2004 Toyota Camry Salvage

Is a salvage care still durable to drive around? It must be otherwise people wouldn't sell it. A salvage car, does it mean that it as in a really bad wreck and someone could possibly die in it? I guess I'm confused as to what 'salvage' means. What part of the vehicle is salvageable and considered usable again? What part of the vehicle is deemed unusable and would need to be reconstructed? A clear example that comes to mind is when a person is involved in a car accident, the person's brain may be intact while the legs and arms may be unsalvageable. This is an ok person. Limbs could be restricted with prosthesis. However, if the brain is affected even though their arms and legs are intact, this person is really not going to ever function optimally. So, please explain to me if it is safe for me to buy a salvage car. The price is significantly cheaper. A salvage car to me is like a person with brain injury while their limbs are intact. Have I misconstrued this?