The spinal cord is a slender cylindrical structure about the width of the little finger. The spinal cord begins immediately below the brain stem and extends to the first lumbar vertebra (L1). Thereafter, the cord blends with the conus medullaris that becomes the cauda equina, a group of nerves resembling the tail of a horse.
The spinal nerve roots are responsible for stimulating movement and feeling. The nerve roots exit the spinal canal through the intervertebral foramen, small openings between each vertebra.
The brain and the spinal cord make up the Central Nervous System (CNS). The nerve roots that exit the spinal cord/spinal canal branch out into the body to form the Peripheral Nervous System (PNS).
Between the front and back portions of the vertebra (i.e. the mid-region) is the spinal canal that houses the spinal cord and the intervertebral foramen. The foramen are small openings formed between each vertebra. These “holes” provide space for the nerve roots to exit the spinal canal and to further branch out to form the peripheral nervous system.