Your spinal nerves are the main nerves in your body. (2023)

Spinal nerves are the main nerves in the body. There are a total of 31 symmetrical pairs of spinal nerves that emerge from different segments of the vertebral column. Each spinal nerve contains sensory and motor nerve fibers. These transmit motor (movement), sensory (sensation), and autonomic (involuntary functions) signals between the spinal cord and other parts of the body.

Spinal nerves can be affected by a variety of medical conditions, resulting in pain, weakness or decreased sensation. ANpinched nerve, which occurs when there is pressure or compression on a spinal nerve, is a common problem.

This article explores the anatomy of spinal nerves and their functions, as well as conditions that can affect spinal nerves and how they are treated.

Anatomy

The spine is made up of vertebrae (back bones) that protect and surround the spinal cord, which is a column of nerve tissue.

Spinal nerves branch off the spinal cord. These areperipheral nerves, or those that travel to other parts of the body and carry messages to and from the brain/spinal cord.

These nerves are located at the cervical (neck), thoracic (upper back), lumbar (lower back), sacral (sacrum, which forms part of the pelvis) and coccygeal (tailbone) levels.

Each pair of spinal nerves is dedicated to certain regions of the body.

Structure

Spinal nerves are relatively large nerves that are formed by the fusion of twonerve roots: a sensory nerve root and a motor nerve root.

Sensory nerve roots emerge from the back of the spinal cord and motor nerve roots from the front of the spinal cord. As they come together, they form the spinal nerves on the sides of the spinal cord.

Spinal nerves receive sensory messages from small nerves located in areas such as the skin, internal organs and bones. Spinal nerves send sensory messages to sensory roots and then to sensory fibers at the back (posterior or dorsal) part of the spinal cord.

The motor roots receive nerve messages from the anterior (front or ventral) part of the spinal cord and send them to the spinal nerves. These messages eventually reach tiny nerve branches that activate muscles in the arms, legs, and other areas of the body.

There are 31 pairs of spinal nerves:

• Eight cervical spinal nerves on each side of the spine calledC1 a C8
• Twelve thoracic spinal nerves on each side of the body calledT1 a T12
• Five lumbar spinal nerves on each side calledL1 a L5
• Five sacral spinal nerves on each side calledS1 a S5
• A coccygeal nerve on each side calledCo1

location

Spinal nerves are evenly distributed throughout the spinal cord and spine. Each spinal nerve leaves the spine by passing through thehole, which are openings on the right and left sides of the vertebrae.

Spinal nerves form a few inches from the spine on each side. Some groups of spinal nerves merge to form a large plexus or network of intertwined nerves. Other spinal nerves divide into smaller branches without forming a plexus.

There are five main plexuses formed by spinal nerves:

• plexo cervical:Composed of the fusion of spinal nerves C1 to C5, these divide into smaller nerves that carry sensory messages and provide motor control to the muscles of the neck and shoulders.
• brachial plexus:Formed by the fusion of spinal nerves C5 to T1, this plexus branches into nerves that carry sensory messages and provide motor control to the muscles of the arm and upper back.
• lumbar plexus:Spinal nerves L1 to L4 converge to form the lumbar plexus. This plexus divides into nerves that carry sensory messages and provide motor control to the abdominal and leg muscles.
• sacral plexus:Spinal nerves L4 to S4 unite. They then branch out into nerves that carry sensory messages and provide motor control to the leg muscles.
• coccygeal plexus:Fusing the S4 to Co1 nerves, this plexus provides motor and sensory control of the genitalia and the muscles that control defecation.

anatomical variation

There are numerous described variants of spinal nerve anatomy, such as roots of multiple connected spinal nerves, initial divisions into nerve branches or missing branches.They are usually discovered during surgery for an injury to the spine, spinal cord, or spinal nerve, or tests are done in preparation for the procedure.

A 2017 study evaluating the spinal nerve anatomy of 33 deceased individuals identified spinal nerve plexus variants in 27.3% of them.This suggests that the variation is not uncommon and does not usually cause noticeable problems.

Occupation

Spinal nerves have small sensory and motor branches. Each of the spinal nerves performs functions that correspond to a particular region of the body. These are muscle movement, sensation andautonomous functions(involuntary functions).

Motor

Motor messages to spinal nerves originate in the brain. The motor band (primary motor cortex) in the brain initiates a command for muscle control. This command is sent to the spine via nerve impulses and then travels through the motor root to the spinal nerve.

Motor stimulation is very specific. You can activate the entire spinal nerve or just one of its branches to stimulate a very small group of muscles, depending on the brain's command.

miotoma, groups of muscles innervated by nerves from a spinal nerve root, are areas of distribution of spinal nerve control throughout the body.

Every physical movement requires one or more muscles, which are activated by one or more branches of the spinal nerve. For example, the biceps muscle is controlled by C6 and the triceps muscle is controlled by C7. Muscles can also be activated by signals transmitted through combinations of multiple spinal nerves.

autonomous

The autonomous or involuntary function of the spinal nerves helps control the body's internal organs, such as the bladder and bowels.

There are fewer autonomic branches of spinal nerves than motor and sensory branches.

Sensorial

Spinal nerves receive messages including touch, temperature, position, vibration and pain from tiny nerves in the skin, muscles, joints and internal organs of the body.

Each spinal nerve corresponds to a skin region of the body, described asdermatoma. For example, sensation near the navel is sent to T10; hand sensation is sent to C6, C7, and C8.

Sensory dermatomes do not fit perfectly with motor myotomes.

Associated conditions

Spinal nerves can be affected by a number of conditions. These situations can cause pain, sensory changes and/or weakness.

Diagnosing a spinal nerve problem involves several steps. The first is the physical examination, which can identify alterations corresponding to a dermatome and/or myotome. Reflexes also correspond to spinal nerves, and are often diminished in these situations as well, which further helps to identify which nerves are involved.

nerve testscan help identify which spinal nerves are involved and how extensive the involvement is:

• electromyography(EMG)uses needle electrodes inserted through the skin into muscles to measure electrical activity in muscle fibers.
• Nerve conduction studies (NCS) use shock-emitting electrodes placed on the skin directly over the nerve to measure nerve function.

The following are possible diagnoses.

herniated disc

The discs act as cushions or shock absorbers for the vertebrae. ANherniated disc, also known asherniated disc, is when some of the gelatinous material in the center of a disc leaks into the spinal canal.

A herniated disc occurs when the vertebral bones and their cartilage, ligaments, tendons and muscles tear, allowing structures to slip out of place. This compresses the spinal cord and/or spinal nerve. Early symptoms may include neck or back pain (usually in the lower back) or tingling in an arm or leg.

A herniated disc can be a medical emergency because it can cause permanent damage to the spinal cord.

Treatment includes oral anti-inflammatory medications, physical therapy, pain relievers or anti-inflammatory injections, and possibly surgical repair and spinal stabilization.

narrowing of the foramen

HimforaminalThe openings through which the spinal nerves pass are not much larger than the nerves themselves. Inflammation and bone degeneration can compress a spinal nerve as it passes through the foramen, causing pain and tingling. This is often described as apinched nerve.

Weight gain and swelling can cause or exacerbate a pinched nerve. During pregnancy, for example, many women experience the symptoms of a pinched nerve.This can resolve after weight loss or even weight redistribution. Some pregnant women notice an improvement in symptoms even before they have the baby, and most have complete resolution after delivery.

There are several treatments for foraminal narrowing, including anti-inflammatory medications and physical therapy. Interventional procedures, such as surgery, are usually not necessary.

Herpes

Herpes, also called herpes zoster, is the reactivation of the virus that causesvaricella. Shingles is characterized by a very painful rash.

After you recover from a chickenpox infection, the virus remains in your body, in a nerve root. If it reactivates later in life, which is usually due to a weak immune system, it causes pain and skin damage in the region innervated by a nerve root or the entire spinal nerve.

A case of herpes usually resolves on its own within three to five weeks, but early treatment with antiviral medication can help it heal a little faster and limit the intensity of the pain.

there is anvaccine that can prevent shingles, however, this is recommended for adults age 50 and older, and particularly for those at higher risk of developing a virus reactivation.

Guillain-Barré syndrome (GBS)

Guillain Barre(GBS), also calledacute demyelinating polyneuropathy, causes weakness of the peripheral nerves. It can affect many spinal nerves at the same time.

GBS usually initially causes tingling in the feet, followed by weakness in the feet and legs, progressing to weakness in the muscles of the arms and chest. Eventually, it can damage the muscles that control breathing. Breathing support with a mechanical ventilator is sometimes needed until the condition resolves.

This disease is caused bydemyelination, which is a loss of protectionmyelin(fat layer) that surrounds each nerve. Once this myelin is lost, the nerves don't work as they should, leading to muscle weakness. The myelin is eventually replaced and the nerves can function again, but medical support is needed in the meantime.

Other similar diseasechronic inflammatory demyelinatingpolineuropatia(CIDP), is a relapsing form of GBS in which symptoms may recur every few months or years, with partial or complete recovery each time.

Medical attention is needed to control breathing and oxygen levels for people with symptoms of GBS or CIDP, with intensive care support as needed.

GBS and CIDP can be treated withintravenous immunoglobulin(IVIG), a therapy given through a vein that suppresses the immune system, or a procedure called plasmapheresis that filters the blood.

Trauma

Spinal nerves can be injured in severe traumatic accidents. Car accidents, falls, or blunt force (such as in a contact sport or intentional injury), for example, can cause swelling, stretching, or tearing of the cervical spinal nerves or cervical plexus.

Heavy lifting, falls, and accidents can injure the lumbar spinal nerves or the lumbar plexus.

Rarely, spinal nerves are injured during a medical procedure, especially during major surgery involving extensive cancer near the spine.

Traumatic spinal nerve injury 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 also affect spinal nerves.

Common causes of neuropathy include chronic excessive alcohol consumption,diabetes,chemotherapyfor the treatment of cancer,vitamin B12 deficiencyand neurotoxic chemicals.

Sometimes the nerves can regain their function, but often the nerve damage is permanent. Treatment focuses on identifying the cause to prevent further damage.

spine disease

Several diseases that affect the spine do not directly damage the spinal nerves, but they can produce symptoms that correspond to them.

Multiple sclerosis(MS, a disorder in which the immune system attacks myelin), vitamin B12 deficiency, spinal cord degeneration, and inflammationmyelopathy(spinal cord compression) are examples of conditions that can cause dysfunction of one or more spinal nerves.

In such cases, the function of the spinal nerves is affected because the nerve fibers in nearby sections of the spine stop sending or receiving messages to and from the spinal nerves.

Meningitis

MeningitisIt is an infection or inflammation of the meninges, which is the lining that surrounds and protects the spinal cord. It can disrupt the function of one or more spinal nerves and is considered a medical emergency.

Meningitis causes fever, fatigue, stiff neck and headaches. It can also cause neurological symptoms such as weakness and sensory loss.

With prompt treatment, meningitis can usually resolve without permanent damage to the spinal nerves.

Cancer

Cancerin or near the spine can infiltrate (invade) or compress the spinal nerves, causing dysfunction. This can cause pain, weakness, or sensory changes involving one or more spinal nerves.

Treatment includes surgical removal of the cancer, radiation therapy, or chemotherapy. Recovery varies depending on the extent of spinal nerve involvement.

rehabilitation

Most of the time, spinal nerve damage is treatable. Mild inflammation can usually be controlled with anti-inflammatory medications, and pain can usually be lessened with over-the-counter pain relievers. Physical therapy and exercise can help relieve pressure and improve posture and muscle tone, reducing pain.

However, the pain can be persistent and severe, requiring more aggressive interventions such as injections or surgery.

Nerve damage that causes sensory loss or muscle weakness can result from extensive or long-lasting spinal nerve damage. Nerves are less likely to heal if they have been sectioned (cut). Physical therapy is generally recommended as a way to optimize function by strengthening muscles fed by healthy nerves.

Surgical repair of spinal nerves is a highly sophisticated procedure with variable results depending on the extent and duration of damage. Nerve function monitoring may be necessary during spinal surgery and spinal nerve surgery to reduce the risk of complications.

Resume

There are 31 pairs of spinal nerves that branch off the spinal cord. Each one performs functions that correspond to a certain region of the body,

Many spinal-related illnesses, viral infections, and traumatic injuries can affect spinal nerves, causing pain, weakness, or loss of sensation.

Treatments for spinal nerve involvement depend on the cause, but full or partial recovery is usually possible.