The spinal cord is major column of nerve tissue that is
connected to the
brain and lies within the vertebral canal and
from which the spinal nerves emerge. Thirty-one pairs of
spinal nerves originate in the spinal cord: 8 cervical, 12
thoracic, 5 lumbar, 5 sacral, and 1 coccygeal. The spinal cord
and the brain constitute the central nervous system (CNS). The
spinal cord consists of nerve fibers that transmit impulses to
and from the brain. Like the brain, the spinal cord is covered
by three connective-tissue envelopes called the meninges. The
space between the outer and middle envelopes is filled with
cerebrospinal fluid (CSF), a clear colorless fluid that
cushions the spinal cord against jarring shock. Also known
simply as the cord.
The writer Reynolds Price (1933- ) called the spinal cord
"the literally irreplaceable cable between my brain and the
rest of my body." (A Whole New Life. An Illness and a Healing.
1994, p. 58)
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