Spinal nerves are the major nerves of the body.
There are a total of 31 symmetrical pairs of spinal nerves that emerge from different segments of the spine.
Each spinal nerve contains both sensory and motor nerve fibers.
Spinal nerves branch out from the spinal cord.
Each pair of spinal nerves are dedicated to certain regions of the body.
As they join, they form the spinal nerves on the sides of the spinal cord.
The spinal nerves are formed within a few centimeters of the spine on each side.
Other spinal nerves divide into smaller branches without forming a plexus.
Function
The spinal nerves have small sensory and motor branches.
Each of the spinal nerves carries out functions that correspond to a certain region of the body.
These are muscle movement, sensation, andautonomic functions(involuntary functions).
Motor
Motor messages to the spinal nerves originate in the brain.
The motor strip (primary motor cortex) in the brain initiates a command for muscle control.
Motor stimulation is very specific.
Each physical movement requires one or more muscles, which is activated by one or more spinal nerve branches.
For example, the biceps muscle is controlled by C6 and the triceps muscle is controlled by C7.
Muscles can also be activated by signals passed down through combinations of multiple spinal nerves.
There are fewer autonomic branches of the spinal nerves than there are the motor and sensory branches.
Each spinal nerve corresponds to a skin region of the body, described as adermatome.
The sensory dermatomes do not match up perfectly with the motor myotomes.
Associated Conditions
Spinal nerves can be affected by a number of conditions.
These situations can cause pain, sensory changes, and/or weakness.
The diagnosis of a spinal nerve problem involves several steps.
The first is a physical examination, which can identify impairment corresponding to a dermatome and/or myotome.
Herniated Disc
Discs act as cushions or shock absorbers for the vertebrae.
This compresses the spinal cord and/or the spinal nerve.
A herniated disc can be a medical emergency because it can cause permanent damage to the spinal cord.
Foramen Narrowing
Theforaminalopenings through which spinal nerves travels are not much larger than the nerves themselves.
This is often described as apinched nerve.
Weight gain and swelling can cause or exacerbate a pinched nerve.
There are a number of treatments for foraminal narrowing, including anti-inflammatory medication and physical therapy.
Interventional procedures such as surgery are not usually necessary.
Shingles
Shingles, also called herpes zoster, is reactivation of the virus that causeschickenpox.
Shingles are characterized by a severely painful rash.
After you recover from a chickenpox infection, the virus remains in your body, in a nerve root.
It can affect many spinal nerves at a time.
It can eventually impair the muscles that control breathing.
Respiratory support with a mechanical ventilator is sometimes necessary until the condition resolves.
Once this myelin is lost, the nerves dont function the way they should, resulting in muscle weakness.
Trauma
Spinal nerves can becomeinjured in major traumatic accidents.
Heavy lifting, falling, and accidents may injure the lumbar spinal nerves or the lumbar plexus.
Traumatic injury of a spinal nerve requires therapy and/or surgery.
Neuropathy
Neuropathy is a disease of the peripheral nerves.
CIDP and GBS are two types of neuropathy.
Most neuropathies involve small nerve branches, but they can affect the spinal nerves as well.
Sometimes, nerves can recover their function, but often, nerve damage is permanent.
Treatment is focused on identifying the cause to prevent further damage.
Treatment of spine disease depends on the cause.
Sometimes the spinal nerve function can fully or partially recover with treatments, such as medication.
It can disrupt the function of one or more spinal nerves and is considered a medical emergency.
Meningitis causes fevers, fatigue, neck stiffness, and headaches.
It can also cause neurological symptoms such as weakness and sensory loss.
With timely treatment, meningitis can often resolve without permanent damage to the spinal nerves.
This can produce pain, weakness, or sensory changes involving one or more spinal nerves.
Treatment includes surgical removal of cancer, radiation, or chemotherapy.
Recovery varies depending on how extensive the spinal nerve involvement is.
Rehabilitation
Most of the time, spinal nerve impairment is treatable.
Physical therapy and exercises can help alleviate pressure and improve posture and muscle tone, reducing pain.
However, pain can be persistent and severe, requiring more aggressive interventions, such as injections or surgery.
The nerves are less likely to recover if they have been transected (cut).
Summary
There are 31 pairs of spinal nerves that branch out from the spinal cord.
Treatments for spinal nerve impairment depend on the cause, but a full or partial recovery is often possible.
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