Health Dictionary
Reliable, easy-to-read patient information on common medical conditions — written in plain language, free of jargon, and grounded in current evidence. Browse the most frequent diagnoses, understand what they mean for everyday life, and learn which steps and questions help you have a focused conversation with your doctor.
Roots of spinal nerves
Introduction
A nerve root is the initial segment of a nerve leaving the central nervous system. It can refer to:
- A cranial nerve root, the beginning of one of the eleven pairs leaving the central nervous system from the brain stem or the highest levels of the spinal cord;
- A spinal nerve root, the beginning of one of the thirty-one pairs oleaving the central nervous system from the spinal cord. Each spinal nerve root consists of the union of a sensory dorsal root and a motor ventral root.