A spinal ganglion is a collection of neurons (ganglion), that is located at the dorsal root (radix posterior) of each spinal nerve.
On each side of each spinal cord segment there is one spinal ganglion, which can be seen as a distension of the nerve root. The spinal ganglia are located in or near the intervertebral foramina of the spinal cord in between two vertebrae.
Spinal ganglia contain pseudounipolar neurons. Their dendrites get the afferent fibres from the body and transmit the incoming electrical information via their axons to the spinal cord. The pseudounipolar spinal ganglion cells conducting pain stimuli form synapses with their central processes in the posterior horn in the substantia gelatinosa of the spinal cord.