Spinal cord:The spinal cord is a primary column of nerve tissue connected to the brain, located within the vertebral canal, and serves as the origin for the spinal nerves. There are thirty-one pairs of spinal nerves that originate from it: 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. Together, the spinal cord and the brain form the central nervous system. The spinal cord comprises nerve fibers that carry signals to and from the brain. It is protected by three layers of connective tissue known as the meninges, similar to the brain. The space between the outer and middle layers is filled with cerebrospinal fluid, a clear, colorless liquid that acts as a cushion to protect the spinal cord from impacts. This structure is often referred to simply as the cord.
