spinal nerven. Any of the 62 paired nerves emerging from the spinal cord, each attached to the cord by two roots, anterior or ventral and posterior or dorsal, the latter provided with a spinal ganglion. American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.spi?nal nerve? n. any of a series of paired nerves that originate in the nerve roots of the spinal cord and emerge from the vertebrae on both sides of the spinal column, each branching out to innervate a specific region of the neck, trunk, or limbs. [1785?95] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.