A trapped nerve is a condition commonly treated by our Chiropractors due to our extensive knowledge and experience of working with the nervous system. Trapped nerve or pinched nerve are the general names given when a person experiences a sharp shooting pain that usually radiates away from one or more areas of discomfort. There can be many causes of a trapped nerve and the term trapped nerve can often be misleading as to what is actually occurring when you experience trapped nerve symptoms.
Anatomy of a Nerve
The nervous system comprises the central nervous system, consisting of the brain and spinal cord, and the peripheral nervous system, consisting of the cranial, spinal, and peripheral nerves, together with their motor and sensory endings.
Nerves are bundles of axons in the peripheral nervous system (PNS) that act as information highways to carry signals between the brain and spinal cord and the rest of the body. Each axon is wrapped in a connective tissue sheath called the endoneurium. Individual axons of the nerve are bundled into groups of axons called fascicles, wrapped in a sheath of connective tissue called the perineurium. Finally, many fascicles are wrapped together in another layer of connective tissue called the epineurium to form a whole nerve. The wrapping of nerves with connective tissue helps to protect the axons and to increase the speed of their communication within the body.
The peripheral nervous system (PNS) includes all of the parts of the nervous system outside of the brain and spinal cord. These parts include all of the cranial and spinal nerves, ganglia, and sensory receptors.
Causes of a Trapped Nerve
A trapped nerve occurs when there is “compression” (pressure) on a nerve. The pressure may be the result of repetitive motions. Or it may happen from holding your body in one position for long periods, such as keeping elbows bent while sleeping. Nerves are most vulnerable at places in your body where they travel through narrow spaces but have little soft tissue to protect them. Nerve compression often occurs when the nerve is pressed between tissues such as:
Common causes of a trapped nerve are: Disc Bulges, Swelling, Piriformis Syndrome, Osteophytic Encroachment as well as Muscular and Fascial Tightness in specific regions.
If nerve compression lasts a long time, a protective barrier around the nerve may break down. Fluid may build up, which may cause:
- Extra pressure
The scarring may interfere with the nerve’s function.
Risk Factors for a Trapped Nerve
The following factors may increase your risk of experiencing a trapped nerve:
- Posture. Poor posture adds pressure to your spine and nerves.
- Gender. Women are three times more likely to develop carpal tunnel syndrome, possibly due to having smaller carpal tunnels.
- Bone spurs. Trauma or a condition that causes bone thickening, such as osteoarthritis, can cause bone spurs. Bone spurs can stiffen the spine as well as narrow the space where your nerves travel, pinching nerves.
- Rheumatoid arthritis. Inflammation caused by rheumatoid arthritis can compress nerves, especially in your joints.
- Overuse. Jobs or hobbies that require repetitive hand, wrist or shoulder movements, such as assembly line work, increase your likelihood of a pinched nerve.
- Obesity. Excess weight can add pressure to nerves.
- Pregnancy. Water and weight gain associated with pregnancy can swell nerve pathways, compressing your nerves.
- Heredity. Some people appear to be genetically predisposed to conditions that lead to pinched nerves.
Classification of Nerve Injury
Nerve injuries are classified by the degree of pathological change in the nerve. There are three main grades (Burnett, Hyde). The mildest injury is classified as grade I, and the most severe as grade III. Grade I nerve injury is called neurapraxia and is a minor injury from which full recovery occurs. With neurapraxia, there is no loss of nerve continuity, and functional loss is temporary. Grade II nerve injury, called axonotmesis, is a more severe injury, and although some secondary reparative processes occur, recovery can eventually take place. With axonotmesis, there is interruption of the internal nerve fibers (axons), but the external structures covering the nerve remain intact. A situation in which the nerve is severely damaged by crushing, laceration, or complete transection is called neurotmesis. This is a grade III injury, and it results in some degree of permanent impairment. With neurotmesis, there is complete functional loss unless surgery to re-attach the nerve is performed.
If a motor nerve is injured, the muscle(s) that the nerve supplies (innervate) loses function. If a sensory nerve is injured, the area innervated by the nerve loses sensation. The closer the nerve is to its origin in the spinal cord, the lower the chance of recovery. Nerve injury also may affect autonomic nerves, which control temperature regulation, blood pressure, heart rate, and digestion.
Symptoms of a Trapped Nerve
- Pain in the area of compression, such as the neck or low back
- Radiating pain, such as sciatica or radicular pain
- Numbness or tingling
- “Pins and needles” or a burning sensation
- Weakness, especially with certain activities
- Muscle spasms
- Sensation changes to temperature and vibration
Sometimes symptoms worsen when you try certain movements, such as turning your head or straining your neck.