Figure 12-7. A typical spinal nerve, with a cross section of the spinal cord.
a. Coming off of the posterior and anterior sides of the spinal cord are the
posterior (dorsal) and anterior (ventral) roots of the spinal nerve. An enlargement on
the posterior root is the posterior root ganglion. A ganglion is a collection of neuron cell
bodies, together, outside the CNS.
b. Laterally, the posterior and anterior roots of the spinal nerve join to form the
spinal nerve trunk. The spinal nerve trunk of each spinal nerve is located in the
appropriate intervertebral foramen of the vertebral column. (An intervertebral foramen
is a passage formed on either side of the junction between two vertebrae.)
c. Where the spinal nerve trunk emerges laterally from the intervertebral
foramen, the trunk divides into two major branches. These branches are called the
anterior (ventral) and posterior (dorsal) primary rami (ramus, singular). The posterior
primary rami go to the back. The anterior primary rami go to the sides and front of the
body, and to the upper and lower members.
Section IV. THE AUTONOMIC NERVOUS SYSTEM
12-10. CONTROL OF VISCERAL ACTIVITIES
The autonomic nervous system (ANS) is that portion of the nervous system
concerned with commands for smooth muscle tissue, cardiac muscle tissue, and
a. The term visceral organs may be used to include: