All tissues are directed by the nervous system.
The brain controls all processes of the body through the nervous system.
Muscles that attached to the back will stiffen up, or spasm, when the spine is injured.
The left side of the picture shows the large superficial muscles of the back. The right side shows the smaller muscles that will often spasm with a spinal injury, causing anything from a stiff neck to a sharp, constant pain. Adjusting the spine and correcting the Subluxation will cause the body to no longer feel the need to spasm, and the muscle will relax.