Correct posture is at the core of the Advanced Spinal Corrective Techniques. The curves in your spine act as levers, shock absorbers, and resistance to gravity; they also protect and reduce forces acting on the spinal cord and nerve tissues. But, gravity, age, poor posture, improper physical activity, injury, and disease can all play a role in the misalignment of your spinal curves and, as a result, your entire body.
Ideal Spinal Alignment: Harrison Full Spine Model
As in all fields of study dealing with the human body, i.e. physiology, hematology, anatomy, etc., there exist normal values for alignment of the spine. The Harrison Spinal Model is an evidenced based model for side view spinal alignment. It is the geometric path of the posterior longitudinal ligament or the backs of the vertebra from the 1st neck vertebra to the bottom of the lower back or top of the sacrum.
Researchers have extensively published ideal and average models for the human spinal curvatures as viewed from the side. This research has led to the finding of the ‘Harrison Spinal Model’. This model details both Ideal and Average geometric shapes for the curves of the spine from the side. Additionally, ideal and average ranges for the spinal segmental angles for each of the spinal regions have been identified. The neck or cervical spine should have a geometric shape that approximates a ‘piece of a circle’. The ribcage or thoracic spine should have a geometric shape that approximates an oval-elliptical shape. And the low back or lumbar spine should have a geometric shape that approximates an oval-elliptical shape.26-31
These are “evidence based” models. In fact, the neck-cervical circular model27 and the low back- lumbar elliptical model29 have both been found to have discriminative validity between pain and non-pain subjects. In other words, the Harrison Spinal Model has been found to be able identify pain subjects versus non-pain subjects by what their spinal x-ray shapes are.
These three figures demonstrate the concept that each spinal region has a normal ‘geometry’ or shape of the spinal curves.
Neck or Cervical Spine
Here the shape in the neck curve should approximate a piece of a circle.
Ribcage or Thoracic Spine
Here the shape in the ribcage should approximate a piece of an oval or ellipse.
Low back or Lumbar Spine
Here the shape in the low back should approximate a piece of an oval or ellipse.
The Harrison Full Spine Model
Here is the exact geometric model of the side view of the spinal curves as identified by Harrison and colleagues. This model can be used to determine what abnormally is wrong with a patient’s side view of the spine. For example, a full spine x-ray on the right is shown. The red-curved line represents the Harrison spinal model and this shows where the patient’s spinal vertebra should be lined up. It is apparent that this patient has altered the spinal alignment as they do not fit even close to the Harrison Idealized Spinal Model.
The Harrison Spinal Model in the Neck-Cervical region
The Harrison spinal model is depicted as the GREEN curved line in this figure. On the Right is a normal curved patient x-ray. On the Left is an abnormal curved patient x-ray; where the patient’s abnormal shape is shown by the Red dashed line. The Harrison Spinal Model in the neck has been shown to reasonably predict which person will have neck pain compared to normal subjects.