conus medullaris
The inferior boundary of the spinal cord typically ends at the level of the L1 or L2 vertebra in most adults.
The most superior boundary of the spinal cord is the foramen magnum.
Medulla Oblongata
most of the neurons in the brain and spinal cord are
The spinal cord is part of the nervous system.
Your brain and spinal cord, for the most part.
The spinal cord is not a bone, it is a collection on nerves connecting the muscles of most of the body to the brain
spinal cord
Your vertebral column protects the spinal cord. Vertebral column is supported by strong ligaments. Most importantly the muscle tone is there, which act on vertebral column, to protect your spinal cord.
Because the spinal cord is a lot of what keeps you alive. It controls all the basic things you need to survive. If you fall and break your spinal cord you will most likely die. It controls thing like breathing and your heart.
The brain and spinal cord are collectively called the Central Nervous Sytem which controls all most of the body's functions including movement.
These are two different problems. Multiple Sclerosis is where areas in the brain and spinal cord lose their protein insulation, and Spinal stenosis is where there is an encroachment on the cord, usually occurring in the lower back area. This is to say that (most likely) arthritis occurs at the end plate (extreme bottom, or top of vertebrae, and the adding on of new bone to those areas causes the spinal canal to become smaller, eventually resulting in pressure on the spinal cord.