The Spinal Cord
The spinal cord is an extension of the brain and serves as its main link, connecting it to the spinal nerves and the rest of the body. It is a long cream colored network of nerves with a cylindrical shape. It is about as thick as a finger or rope and is approximately 17 inches long. It weighs between 1.2 and 1.4 ounces. The spinal cord leaves the brain through a large hole in the base of the skull and stretches from the base of the cerebral stem down the back. The spinal cord is located inside of the spinal column which keeps the body erect. The spinal column is constructed of individual bones called vertebrae. Each of the 33 vertebrae has a hole in the center and stack on top of one another forming a tube to house the spinal cord. The hard bony column and the muscles in the back protect the spinal cord. The spinal cord is protected further by the three layers of meninges and cerebrospinal fluid surrounding it. The vertebrae are not joined together but are instead separated by disc of soft tissue. This cushions the movement of the spinal column and allows for twisting and turning. Theses spaces in between the vertebrae also serve as the point from which the spinal nerves extend into the body. Thirty one pairs of spinal nerves extend outward from each of the thirty one segments that the spinal cord is divided into. The spinal nerves branch out and get smaller as they extend to reach all points in the body in order to carry the signals between the brain and body (Farley et al., 2014) (Oleksy, 2001) (Parker, 1997) (Roca & Serrano, 1996) (Walker & Wood, 2003).