posterior root vs spinal nerve root

posterior root and spinal nerve root both are nouns.

Word	Noun	Adjective	Verb	Adverb
posterior root	Yes	No	No	No
spinal nerve root	Yes	No	No	No

posterior root (noun)	spinal nerve root (noun)
one of two roots of a spinal nerve that passes dorsally from the spinal cord and that consists of sensory fibers	one of two roots of the spinal nerves