Hind rot

Radix posterior

Dorsal root

Bundle of 10,000's of afferent "sensory" nerve fibers, both myelinated and unmyelinated and of all sizes where the thickness of the axonvaries from 0.1 up to about 20 micrometers.

The hind root extends from the posterior ganglia/spinal ganglia to the posterior surface of the spinal cord.

Each spinal cord segment receives one hind root on its right side and one on its left side. The posterior filaments have their cell bodies in the posterior ganglia/spinal ganglia.

Upon entry into the spinal cord, the coarser myelinated threads make their way into the back cord. Once there, each hind root thread divides into several smaller branches that "run" into the hind horn and into an ascending "main branch".
The smaller branches are distributed locally in the gray matter at the entry level. Here, different types of internal neuron and in some cases also motor neurons are contacted.
The ascending "main branch" in turn, on its way to the brain, emits a large number of lateral branches into the gray matter. There are also descending branches in the back string.

Upon entry into the spinal cord, the small myelinated (A-delta) and unmyelinated (C) filaments of the hind root enter directly into the hind horn where they end, perhaps after branching a segment up and down, and the nerve signals, here pain and temperature stimuli, are switched to a new neuron.

The uppermost spinal cord segment - C1 - usually lacks the hind root and hind root ganglion.