The spinal cord is the elongated,almost cylindrical part of the central nervous system,which is suspended in the vertebral canal surrounded by the meninges and cerebrospinal fluid. The spinal cord is continuous above with the medulla oblongata and extends from the upper border of the atlas to the lower border of the 1st lumbar vertebra. A specimen of cerebrospinal fluid can be taken using a procedure called lumbar puncture.
Except for the cranial nerves,the spinal cord is the nervous tissue link between the brain and the rest of the body. Nerves conveying impulses from the brain to the various organs and tissues descend through the spinal cord. At the appropriate level they leave the cord and pass to the structure they supply. Similarly sensory nerves from organs and tissues enter and pass upwards in the spinal cord to the brain.
Some activities of the spinal cord are independent of the brain and are controlled at the level of the spinal cord by spinal reflexes. To facilitate these,there are extensive neurone connections between sensory and motor neurones at the same or different levels in the cord.
