Nerve root
A nerve root is the starting portion of a nerve that branches off to either side of the spinal cord—literally, the root of a nerve. Nerve roots pass through narrow openings between the vertebrae and extend toward the arms, legs, and trunk, carrying sensory and motor signals. When a nerve root is irritated, you may feel pain that travels along the band-shaped area supplied by that nerve (Radicular pain).
Where are they, and what do they do?
Nerve roots branch off from both sides of the spinal cord, with one pair at each spinal level. The Korean term comes from Chinese characters meaning “nerve” and “root,” and the English term is also “nerve root.” From the neck vertebrae (cervical spine) down to the sacrum near the pelvis, they are classified by level as cervical, thoracic, lumbar, and sacral nerve roots.
After leaving the spinal cord, nerve roots travel a short distance within the Spinal canal, then exit the spine through narrow openings called intervertebral foramina. They then merge and divide into multiple branches, reaching the skin and muscles of the arms, legs, and trunk.
The anterior and posterior roots join to form a single spinal nerve. The anterior root carries motor signals that move muscles, while the posterior root carries sensory signals coming from the skin and joints. Each nerve root has its own specific territory: its area of skin sensation is called a Dermatome, and its muscle territory is called a Myotome. The location of symptoms can therefore provide a useful clue to the level of the affected nerve root.
How it can feel in everyday life
The intervertebral foramina through which nerve roots pass are narrow, making them sensitive to changes in the shape of surrounding structures. This is because tissues such as the intervertebral discs, facet joints, and ligamentum flavum lie close to these openings. For example, in Lumbar disc herniation, the jelly-like tissue inside the disc, called the Nucleus pulposus, can push outward and irritate a nerve root next to the protrusion. Common symptoms include:
- Pain that travels along a distinct path from the buttock into the leg, or from the neck into the arm
- Numbness or tingling in particular fingers or toes
- A shooting, electric pain when coughing or sneezing
This radicular pain, which originates in the nerve root itself, feels different from referred pain that starts in muscles or joints and spreads broadly as a dull ache. In addition to Lumbar disc herniation, several factors can irritate nerve roots, including Lumbar spinal stenosis and changes that enlarge the facet joints.
One thing to remember is that it is not uncommon for people to have no symptoms even when imaging shows a disc protrusion near a nerve root. Structural changes seen on imaging do not always match the symptoms a person experiences. An assessment therefore considers imaging findings alongside the precise location of symptoms, whether muscle weakness is present, and changes in sensation.
Ways to manage it
1. Avoid staying in the same position for too long. If you work sitting down, getting up and taking a short walk every 30–60 minutes can ease the load around your spine. 2. Notice which positions cause pain to travel. Keeping a record of which positions worsen or ease your symptoms can help when explaining your condition. 3. Keep heavy objects close to your body when lifting. Rather than bending only at the waist and pulling, bending your knees and keeping the object close to your trunk as you lift can reduce strain. 4. Keep up low-impact activities such as walking. Rather than stopping all movement because of pain, many people continue moving a little at a time within a comfortable range.
A clear loss of strength in an arm or leg, a gradually expanding area of numbness or tingling, or changes in bladder or bowel sensation are signs that need attention. If these changes occur, it is advisable to have your condition assessed without delay.