The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal cord is hollow and contains a structure called the central canal, which contains cerebrospinal fluid. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.