Nerve · Thoracic spine

Dorsal root ganglia

Ganglia sensoria nervi spinalis

The bead-like swelling carried by every dorsal root, sitting in or just outside the gap between two vertebrae. It is not a junction box and nothing is relayed inside it: it is a residence. The cell bodies of the sensory neurons live here, each with a single stalk that splits so one arm reaches out to the skin, muscle or joint and the other runs into the spinal cord — meaning the signal passes the cell without ever entering it. Almost everything you feel from the neck down passes a ganglion like this one, and because they sit outside the cord, the cell bodies for a whole segment's sensation are gathered together inside the narrowest part of the channel that segment has to leave by.