Nerve · Thoracic spine

Ventral nerve roots

Radices ventrales

The outgoing half of every spinal nerve — the wires leaving the cord rather than arriving at it. Rootlets emerge from the front-and-side surface of the spinal cord at each segment and gather into a ventral root that runs out to meet the dorsal root at the intervertebral foramen. Its fibres come from nerve cells sitting inside the cord itself, in the anterior horn, so unlike its sensory partner it carries no ganglion and has no swelling along its course. Between the first thoracic and second lumbar segments, and again at the second to fourth sacral, it also carries the autonomic fibres heading out to blood vessels, sweat glands and organs — which is why a root can matter for far more than the muscle it moves.