Glossary
Dorsal Root Ganglion
What is a dorsal root ganglion?
A dorsal root ganglion (DRG) is a cluster of sensory neuron cell bodies along a spinal nerve’s dorsal root. These neurons carry information about touch, temperature, pain, and other sensations from the body toward the spinal cord.
How it is built
The neurons are pseudounipolar: each has an axon that branches in two directions. One branch extends toward the body’s tissues; the other enters the spinal cord. The ganglion houses the cell body, rather than serving as an ordinary synapse where one sensory neuron hands the signal to another.
Dorsal root ganglia commonly sit in or near the openings between vertebrae, called intervertebral foramina. Their exact positions vary. Sensory fibers enter through the dorsal roots, while motor fibers leave through the ventral roots; the two roots join to form a spinal nerve.
Why it matters
Changes in the excitability of these sensory neurons can contribute to pain and other sensory disturbances. The ganglion is therefore more than an anatomical landmark: its cells can influence the signals reaching the central nervous system.
A clinical research example
Small-fiber neuropathy can involve pain in the hands or feet. In a 2012 study, Han and colleagues investigated sodium-channel variants found in patients with this condition. Laboratory tests showed that the variants made DRG neurons more excitable. Sodium channels help generate electrical signals, so a change in their behavior offers a specific route by which sensory signaling can become abnormal.
These laboratory findings link a molecular change to how sensory neurons function. They do not mean that every case of neuropathy or chronic pain has the same cause, or that the findings identify a treatment for an individual patient.