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The dorsal root ganglion

The swelling on each dorsal root that holds the cell bodies of the body's sensory neurons. Why those neurons have a single split process, and what surrounds them.

Updated 2026-10-023 sources

Depth:

Why it matters

Touch, pain, temperature and position sense from the trunk and limbs all begin in neurons whose cell bodies sit in a dorsal root ganglion. Both the dorsal column pathway and the spinothalamic tract begin with these neurons [1].

What it is

A ganglion is a group of neuron cell bodies outside the central nervous system, and the most common type of sensory ganglion is the dorsal root ganglion [2]. Its neurons have sensory endings in the periphery, such as in the skin, and axons that extend into the central nervous system through the dorsal root [2]. The ganglion is an enlargement of the nerve root [2].

How it works

The cells of the dorsal root ganglion are unipolar by shape [2]. In humans these cells are more properly called pseudo-unipolar: an axon emerges from the cell body and splits, so that it can extend over a very long distance [3]. Unipolar cells are exclusively sensory neurons, and their cell bodies are always in ganglia [3].

Satellite cells, a type of glial cell, surround the cell bodies of neurons in sensory and autonomic ganglia [3]. In the ganglion's fibrous region, axons pass through on their way to become part of the dorsal root [2].

Common misconceptions

Misconception: Sensory neurons have their cell bodies in the spinal cord.

The first sensory neuron's cell body lies outside the cord, in the dorsal root ganglion; its axon enters the cord through the dorsal root [2].

Check yourself

What shape are dorsal root ganglion neurons?

Unipolar, more properly pseudo-unipolar: one process that splits [2, 3].

Which glial cells surround the neurons in a ganglion?

Satellite cells [3].

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References

  1. Betts JG, Young KA, Wise JA, Johnson E, Poe B, Kruse DH, et al.. 14.2 Central Processing. Anatomy and Physiology 2e. OpenStax. 2022. https://openstax.org/books/anatomy-and-physiology-2e/pages/14-2-central-processing
  2. Betts JG, Young KA, Wise JA, Johnson E, Poe B, Kruse DH, et al.. 13.4 The Peripheral Nervous System. Anatomy and Physiology 2e. OpenStax. 2022. https://openstax.org/books/anatomy-and-physiology-2e/pages/13-4-the-peripheral-nervous-system
  3. Betts JG, Young KA, Wise JA, Johnson E, Poe B, Kruse DH, et al.. 12.2 Nervous Tissue. Anatomy and Physiology 2e. OpenStax. 2022. https://openstax.org/books/anatomy-and-physiology-2e/pages/12-2-nervous-tissue

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