The spinal cord stretches along the entire spine. In adults it ends at the second level of lumbar vertebra in the shape of a cone (conus medullaris) whose tip is the beginning of the final filament (filum terminale) that creates the formation of cauda equine with the roots of the lowest spinal nerves.
Nature has made it that way. Each muscle, ligament, and nerve has its own place not being in the way of anything else.
However, it happens that because of an injury, swelling presses the nerve and at that moment pain, spasms, and disfunction occurs; life may be complicated quite a lot.
To avoid all such unpleasantness, it is necessary to follow certain rules both in everyday activities and exercising.
