The posterior ramus of spinal nerve (or posterior primary division) refers to the posterior division of a spinal nerve. The ramus is also known by a number of other names, “posterior (or dorsal) rami (or branches or divisions) of the spinal nerves”. The posterior ramus is one of two major branches of a spinal nerve that emerge after the nerve emerges from the intervertebral foramen. The posterior ramus carries information that supplies muscles and sensation to the human back.

see Lumbar dorsal rami