Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Spinal Cord Injuries ?
    ### Response:
    Your spinal cord is a bundle of nerves that runs down the middle of your back. It carries signals back and forth between your body and your brain. A spinal cord injury disrupts the signals. Spinal cord injuries usually begin with a blow that fractures or dislocates your vertebrae, the bone disks that make up your spine.
    