The Horizontal Neurologic Levels
We would all like to thank Dr. Richard C. Schafer, DC, PhD, FICC for his lifetime commitment to the profession. In the future we will continue to add materials from RC’s copyrighted books for your use.
This is Chapter 4 from RC’s best-selling book:
“Basic Principles of Chiropractic Neuroscience”
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Chapter 4: The Horizontal Neurologic Levels
and Related Clinical Concerns
This chapter describes the basic functional anatomy and clinical considerations of the horizontal aspects of the supratentorial, posterior fossa, spinal, and peripheral levels of the nervous system.
The reader should keep in mind that the various aspects of the nervous system as described in this manual (eg, longitudinal and horizontal systems) are only reference guides that are visualizations of a patient’s nervous system in the upright position. They can be likened to the lines of longitude and latitude on a globe of the earth.
Such systems do not exist physically, but they do serve as excellent mental grid-like tools (viewpoints) during localization and areas in which and from which relationships can be described. For example, although the longitudinal systems take a general vertical course within the spinal column there are numerous alterations and they actually become horizontal when decussating. While the horizontal levels are spatially placed in and extend from the CNS in a general segmental manner, they soon take a widely diffuse course as they project toward their destinations. Thus, references to longitudinal and horizontal levels are just general viewpoints.
It is helpful for study purposes to isolate the body into certain systems, as described above, organize systems into organs, organs into tissues, tissues into cells, and cells into their components. However, we should keep in mind that, physically and functionally, there is only one integrated body and it is more than the sum of its parts. And even the body cannot be thought of as truly separate from its external environment. Although we may do this for study purposes, it is a limited viewpoint.