Spinal Mechanics

Synergetic Spinal Mechanics and PPT Manipulation  

Synergetic Spinal Mechanics and PPT Manipulation

Experimentation

 

SPINAL EXPERIMENTATION AND FRYETTE'S LAWS

The spine and sacroiliac joints work in synergetic harmony.

 

It is impossible to look at a single joint or series of joints in a certain area such as the sacroiliac, lumber, thoracic or cervical in isolation because the body does not work like that.  The body works as a complete interacting mobile unit.

 

When Looking at spinal articulation where do you start?

Answer: by examining  one of the most basic human movements: walking

 

Leaving aside muscles, walking involves many different forces, the main ones being:

  

  •  Weight bearing and weight leaning

 •  Weight lifting and leg direction

 •  The changing angles of the ilia and hip joints

  •  The reciprocal action of the sacroiliac joints

  •  The lumbar vertebrae accommodation for this action and;

 •  The action of side-shift

 

Walking involves a very complicated three dimensional set of protocols that need to work in harmony.

 

 

Let’s take a look at the way the third lumbar vertebrae side-bends and rotates to accommodate the walking action.

First we need to check the way L3 articulates. Here are a couple of tests to prove or disprove “Fryette’s” laws. “Fryette” stated that in forward bending the third lumbar vertebra rotates and side-bends to the same side. In backward bending and upright posture it side-bends and rotates to opposite sides.  

 

Test A for rotation

Ask a colleague to sit sideways on a plinth with their back straight and their feet firmly on the floor. Their weight must be equally balanced on both buttocks. Stand or squat behind the colleague and place your hands around their pelvis in such a way as to completely immobilize it. In this way the lumbar rotation is isolated. If muscles are the singular cause of lumbar rotation the L3 joint will rotate.

 

Ask your colleague to rotate slowly in either direction and be very careful not to force the movement. This will lever the pelvis, so take care to immobilize the movement in all planes to remove this factor. This is more difficult than it sounds but it must  be done. A way to double check if any rotation is coming from the pelvis is to carefully watch or feel the knees for any  movement.

 

The result of this test is that the spine locks after only a few degrees of rotation. Similar findings were more precisely recorded in Dr Kapandji’s book on page 119.

 

 

Test B for side-bending

So we know the joint cannot rotate very far when the pelvis is immobilized. So let’s test side-bending. If the test above is repeated but instead of rotation side-bending is attempted, we find side-bending is also restricted to only a few degrees.

 

 

Test C  for combined side-bending and rotation

Next we need to check what happens in the lumbar when side-bending and rotation are combined with the pelvis immobilized. Again, be sure not to allow even small amounts of pelvic movement to influence your results.  Ask the colleague to side-bend their lumbar as best they can and then attempt rotation to the opposite side.  If “Fryette's” laws  are correct this combination movement should account for real world lumbar rotation. However, the amount of rotation possible is still minimal and the lumbar vertebra if forced to rotate further L4/L3 will quickly lock.

 

So what has been learned from these primitive experiments?

These simple tests indicate that isolated combinations of side-bending and rotation in the lumbar spine, most certainly do not account for the amount of lumbar rotation a normal person takes for granted in the real world. Judging by the leverage placed on the pelvis during the tests, the pelvis has a role to play in lumbar rotation. If so, we need to establish its role. To find this out we need to experiment further.

 

Test D adding pelvic side-bending

With  your colleague in the same position on the plinth as in test C, place a book approximately  25 mm thick under their right ischial tuberosity so as to side-bend the sacrum to the left. The weight of the body is thus taken on the left buttock. If the person sits up straight the lumbar becomes side-bent to the left.

 

Now ask you colleague to rotate to the right. Be sure to block all pelvic side-shift to the left.

 

The result is that your colleague will be able to rotate further to the right in the lumbar than when the sacrum was horizontal. The test proves that side-bending of the pelvis improves the degree of lumbar rotation.

 

The Pelvis

From our tests, pelvic side-bending plays an important part in lumbar rotation. So let’s look at how the “Three Pole” and ”Nutation” sacroiliac theories accommodate the action?  

 

The pelvis is designed to accommodate the actions of the hip joints, the sacro-lumbar joints, the synthesis pubis joint and the sacroiliac joints.

For a real world theory to apply to the pelvic articulations, the theory has to fulfil working criteria. These criteria are:

 

1  It has to account for the walking action of the legs.  

 

2  It has to account for the way the vertebral spine moves to complement the walking mechanism.

 

3  It has to act as a precursor for the vertebral spine to side-bend and rotate in both forward and backward bending.

 

4   It has to act as a precursor for the thoracic spine to rotate in lumbar extension.

 

5   It should not dislocate when completing items 1, 2, 3 and 4.

 

Continued