Dorsal ramus of spinal nerve

Dorsal ramus of spinal nerve
Diagram of spinal nerve
Areas of distribution of the cutaneous branches of the posterior divisions of the spinal nerves. The areas of the medial branches are in black, those of the lateral in red.
Details
Identifiers
Latin	ramus posterior nervi spinalis
TA98	A14.2.00.035
TA2	6151
FMA	5983
Anatomical terms of neuroanatomy [edit on Wikidata]

The dorsal ramus of spinal nerve, posterior ramus of spinal nerve, or posterior primary division is the posterior division of a spinal nerve. The dorsal rami provide motor innervation to the deep (a.k.a. intrinsic or true) muscles of the back, and sensory innervation to the skin of the posterior portion of the head, neck and back.^[1]

A spinal nerve splits within the intervertebral foramen to form a dorsal ramus and a ventral ramus. The dorsal ramus then turns to course posterior-ward before splitting into a medial branch and a lateral branch. Both these branches provide motor innervation to deep back muscles. In the neck and upper back, the medial branch is also responsible for providing sensory innervation of the skin; in the lower back, the lateral branch does so. All medial branches additionally also provide sensory innervation to the zygapophyseal joints and periosteum of the vertebral column.^[1]