I’m Doctor Mark Weaver. I’m a podiatrist here in Fort Myers, Florida. We are here today to talk about how ankle and subtaylor joint– this is the subtalor joint pronation will effect the low back causing pain in the low back at the level of the lumbar sacrum and the sacroiliac joints. Let’s go look at an x-ray. This is the subtalor joint. This is what they call a cyma line (see video). Notice the cycle shape or the “S” shape caused by these two joints. Now let’s look at a chart. Here we have a lateral diagram of a normal foot. Notice the cyma line is a straight line not “S” shape as when we x-ray of the patient of the pronated foot. Now let’s look a 3 dimensional bone figure. Here we see on the three dimensional model the cyma line which is a straight line. This is indication that the foot is not pronated. If we turn the model around, we will see that there is a good high arch. Now, if we flatten the arch out. We will turn the back around and we can see the “S” shape with the pronation of the foot.
This is the normal foot. Notice the leg bone is vertical. If we pronate this foot, notice how the leg bone rotates inward. This puts pressure on the outside of the knee. If we look at the skeletal model we will be able to see how these forces affect the rest of the body. Here with the full skeletal model we can see the affects of this pronation. When the foot flattens out it twist the leg bone inward on the knee. That causes extra pressure at the level of the lateral knee. Now the knee is great joint for strength but it only has one range of motion – back and forth. It cannot bend this way. So, since it cannot bend that way it directs the pressure of the torque into leg bone.
The next joint to be affected will be the hip joint. The hip is a very good joint. It bends all sorts of directions because it is a bone socket. In fact the only direction it can’t bend is in and out. So consequential, this pressure cannot be absorbed because it is in and out. The pressure is then pushed into the pelvis which slides back and forth as a solid unit because the bones are fused.
The next place to accept this pressure is the L5S1 juncture. Since this can’t move in the back and forth motion either. It starts to wear this joint out. As it wears this joint out the motion becomes diminished and you will start to see herniated discs at the L5 and L4 area, thus resulting in sacroiliac pain and lower lumbar pain.
Now we have demonstrated how a small amount of pronation in a small joint in the foot can result in problems with the knee, the hip, the sacroiliac joint, and lumbar sacral joints - all from just a small amount of pronation.
Now let us take a look at what we can do about this. By simply bringing support under this area we can stop much of this torque which makes the other portions of the body deteriorate. We can do this using an orthotic device. The orthotic device functions simply by bringing the ground up to the foot and not letting the foot smash down to the ground. This should help diminish pain in the upper body as well as in the rest of the foot.