• Subluxation: The original Gonstead definition involves a complex that includes a misaligned vertebra that is maintained in a sustained position; the shifting of the vertebral body so that it compresses the intervertebral disc and exerts pressure on the nucleus pulposus, thereby forcing it against the anulus fibrosus; the exertion of sufficient pressure by the bulging nucleus pulposus onto the anulus fibrosus and the resultant stretching of the anular fibers to the point that they become damaged or deranged; soft tissue damage of the vertebral motor unit which leads to an inflammatory reaction that causes intracellular edematous fluid to infuse the disc which expands and protrudes; disc protrusion compresses neural structures within the spinal canal or in the intervertebral foramen; and compression of the neural structures that causes nerve pressure that results in nerve dysfunction and leads to altered function and disease. (Herbst RW Intro. p.iii) The spine cannot function properly or remain stable if the pelvis is not level. The basis for the “level foundation” is the measurement of a line drawn through like points on each femur head, usually the superiormost aspect of each femur head. If the pelvis does not become level and the spine cannot accommodate or adapt to leg length deficiencies through adjustment of the spine or pelvis, the Gonstead chiropractor may be required to correct joint dysfunction in the lower extremities. In some cases a heel or sole lift may be required if an anatomical leg length inequality exists. In actual practice, some people fully adapt to leg length differences, and nothing is required except keeping the spine subluxation-free and fit.
  • Compensation: A compensation is often an adaptation, response, or over-response to a subluxation or other structural malposition by functional segmental level either above or below a subluxation. It is roughly based upon the law of force that that says “for every action, there is an equal and opposite reaction.” (Herbst RW p.v) It is usually self-correcting when the subluxation is corrected. (Cox WA 1982) If chronic, it may become a pathological locus or a subluxation itself. A compensatory vertebra often appears more misaligned than a subluxation. Initially, they are hypermobile and may be painful or symptomatic – possibly due to nerve facilitation. According to Dr. Gonstead, the ability to distinguish between subluxation and compensation is a vital clinical skill and makes a difference whether a patient is helped or not. (Herbst Intro.p.v) In the cervical spine, the upper cervical vertebrae, C1 and C2, and C5 are often found in compensation. They are the more highly mobile segments in the cervical spine.
  • Level Foundation: A good, level foundation is vital to a structure. According to Dr. Gonstead, the same holds true to a human body. (Herbst RW Intro.) In the Gonstead Technique, the pelvis is the foundation or base. A line linking the uppermost points of both femur heads is the base level.
  • Level Vertebra: When scolioses are present, the level vertebra is one that is parallel to the horizontal plane and adapts unequal leg length deficiencies and other alterations to the horizontal plane.
  • Parallel disc: The radiograph is the primary tool of the chiropractor to provide insight into the health of an intervertebral disc. Dr. Gonstead stated that there should be equal distance along all points of the opposing vertebral body surfaces that form a disc space on both the AP and lateral films. Drs. Gonstead and Cox stated that the normal spinal curves are primarily due to the wedged shape of the vertebral bodies, not wedging of the discs. (Herbst RW p.52) If there is equal distance at all points throughout the disc space, the height of the disc space is what is expected of that level, the adjacent vertebral body margins align, spinal curves are within normal limits, and no other abnormal physical signs are present, the motor unit is probably normal and these vertebrae are said to be in what Dr. Gonstead called optimal relationship. (Herbst RW pp.51-52) This is a controversial issue as many spine specialists consider a slightly wedged-shaped disc space (on the lateral view, –X in the cervical and lumbar spine and +θX in the thoracic spine) to be within normal limits – it is stated that the normal lumbar curve appears to be formed by both the shape of the vertebral body and the shape of the disc. In order for the lines drawn on the lateral cervical x-ray view to converge posteriorly as is considered normal, there must be slight wedging (–X) of the disc. If the opposing articular surfaces above and below the disc are not flat (not uncommon), a slight AP (–X) wedging is probably within normal limits as long as the vertebral body margins align.
  • Fixation: This is articular hypomobility where the articulation cannot achieve its physiological limits and is beyond merely myotendinous or ligamentous hypomobility.
  • “Mixing Systems”: (sympathetic and parasympathetic nervous systems) A controversial concept in the Gonstead Technique is the matter of clinical separation of the sympathetic and parasympathetic nervous systems. The idea is that the spine cephalad to C6 and caudad to L5 has a primarily parasympathetic influence while C6 to L5 have a strong sympathetic influence. As we all know, there is communications between both systems. The key word for those espousing separating the systems when adjusting is to decide which system is “more influential” in a particular region. When subluxations are found in a “sympathetic” region and a “parasympathetic” region, and especially if the patient is unhealthy” or debilitated and/ or has an organic, systemic, or visceral-type presentation, the doctor chooses to adjust the subluxation(s) only in “one system” on a particular visit. Most Gonstead chiropractors will “mix or cross systems” if the patient is perceived to have musculo-skeletal-only presentation and subluxations are found in both – e.g., adjust C3 and T9. A secondary effect of bserving this “rule of thumb” is to minimize the number of segments adjusted on a single visit.
  • “Crossing Systems”: see ”Mixing Systems.”