Facts on File Encyclopedia of Health and Medicine

that support survival such as respiration,BLOOD
PRESSURE, and HEART RATE. COMPUTED TOMOGRAPHY
(CT) SCANor MAGNETIC RESONANCE IMAGING(MRI) can
show the full extent of the injury.

Treatment Options and Outlook

The standard of care is to administer an intra-
venous corticosteroid medication, methylpred-
nisolone, within eight hours of a spinal cord. The
methylprednisolone reduces the body’s natural
inflammatory response, lessening the risk for
added pressure within the spinal canal and the
direct damage to neurons that INFLAMMATION
causes. Other treatment options may include sur-
gery to stabilize the spine and remove any BONE
fragments or debris from the spinal canal or using
braces to immobilize the spine. Supportive meas-
ures such as MECHANICAL VENTILATIONmay be neces-
sary, depending on the level of the injury.
Ongoing treatment typically includes early and
aggressive PHYSICAL THERAPY, OCCUPATIONAL THERAPY,
and other rehabilitation approaches to maintain
MUSCLEtone and STRENGTHas well as to restore as
much independence as possible. Much of this
treatment may take place at an inpatient rehabili-
tation center that specializes in spinal cord
injuries. Many people are able to recover to a rea-
sonable level of function through the use of
mobility aids and assistive devices. When the
injury is incomplete, full recovery is sometimes
possible. However, it is difficult for neurologists to
predict what level of recovery is likely. An individ-
ual’s general health condition, motivation, and
persistence are important influences.

Risk Factors and Preventive Measures

Measures that reduce the risks for spinal cord
injury are those that lower the likelihood of motor
vehicle accidents. Many of these risks are behav-
iors such as excessive speed, driving while intoxi-
cated, and failure to wear seat belts. Proper
technique and equipment for athletic activities
such as horseback riding, downhill skiing, bicy-
cling, and contact sports help improve the safety
of participating in these events.
See also CORTICOSTEROID MEDICATIONS; NEURON;
NEUROTRANSMITTER; QUALITY OF LIFE; TRAUMATIC BRAIN
INJURY(TBI).

spinal nerves The 31 paired nerves that branch

from the SPINAL CORD, extending into the body to

form the PERIPHERAL NERVES. The spinal nerves and

the CRANIAL NERVEStogether make up the PERIPH-

ERAL NERVOUS SYSTEM. The spinal nerves emerge

from the gray matter of the spinal cord in two

roots. The ventral (anterior or front) spinal NERVE

root is the motor portion of the spinal nerve that

carries nerve impulses from the BRAINand spinal

cord to the peripheral body. The dorsal (posterior

or back) spinal nerve root is the sensory portion of

the spinal nerve that carries nerve impulses from

the body to the spinal cord and brain. Each spinal

nerve root immediately branches into several

rootlets, which subsequently give rise to the

peripheral nerves that serve the body (excluding

the head and face).

SPINAL NERVE PAIRS

cervical: 8 pairs, designated C1 through C8

thoracic: 12 pairs, designated T1 through T12

lumbar: 5 pairs, designated L1 through L5

sacral: 5 pairs, designated S1 through S5

coccygeal: 1 pair, designated CO1

Spinal nerve pairs C1 through C4 serve the neck

and are collectively referred to as the cervical

plexus. Spinal nerve pairs C5 through T1 serve the

upper extremities and main trunk and are collec-

tively known as the thoracic plexus. Spinal nerve

pairs L1 through L5 (the dorsal roots of L4 and L5)

serve the lower back and legs and are collectively

referred to as the lumbar plexus. Spinal nerve pairs

L4 (the ventral roots of L4 and L5) through S3

serve the structures of the lower abdomen and are

collectively known as the sacral plexus. Spinal

nerve pairs S4, S5, and CO1 serve the structures of

the pelvis, including the genitals, and are collec-

tively known as the pudendal plexus.

For further discussion of the spinal nerves

within the context of the structures and functions

of the nervous system, please see the overview

section “The Nervous System.”

See also MULTIPLE SCLEROSIS; SPINA BIFIDA; SPINAL

CORD INJURY.

stupor A state in which a person is unaware of

and does not interact with the external environ-

284 The Nervous System