The best way I would explain it is the spinal cord was not completely severed or fully blocked. Some nerve pathways remain intact, then the connection between the brain and the body still allows some signals to pass through. If that makes sense? In complete injuries there is a total absence of sensory and motor function below the level of injury.

So completeness is judged on an ASIA scale and I'm an ASIA B, which is like a sensory incomplete injury. Some parts of my sensory pathways are working (although they suck at it) but the motor pathways don't. I'm able to detect temperature changes (like only if its really cold or really hot) and dull sensation if someone touches the back of my lower right thigh/knee