The Hinge (Part 3 of the "Oh My Gosh, I have..." blog series)

The final part before we get into actual conditions, of the “Oh My Gosh, I Have…” series will focus on the Ankle joint and its importance with foot function. Part 1, We Are Just a Bunch of Moving Parts!, laid the framework of understanding body mechanics.  Part 2, The Core, described the reality of what the core is and its importance in integrating and allowing movement to occur properly.  If you haven’t read these articles, be sure to read them (click on the links) to put this and the rest of the articles into proper context.

If I’m talking about the Ankle, why did I title the article, The Hinge?

To truly understand how the body interacts with the foot, the best (though not perfect) analogy that comes to mind is that of a door.  The door jamb would be the foot, the hinge would be the ankle and the door would be the body.  The door being the body implies that the body should maintain posture as it passes over the feet.  The movement only occurring at the hinge (ankle) as the door opens and closes (body moves forward over the feet).  Of course, the knee, hip and many other joints move in the body as well, but the postural alignment should still be maintained which is the key point.

What happens when the Ankle functions properly and movement occurs as it should?

As the body makes its pass over the foot, the ankle (a hinge joint!) allows the forward movement to occur, along with some rotation, over the dome shaped Talus (otherwise known as the ankle bone).  When body weight shifts forward, the foot is allowed to remain inherently stable.  See figure 1 below.

 

Figure 1: Normal foot and ankle 

The white line follows the inner column of the foot.  When the column of the foot forms a straight line, the body has a chance to move over the foot at the ankle joint.

What if the Ankle doesn’t function properly?

If the body moves forward over the foot, and the ankle doesn’t bend, then movement that was supposed to pass through the ankle (Hinge) will be forced somewhere through the foot.  The ankle is a single joint, optimally designed to allow the body to move forward without stressing the foot too much.  The foot is made up of many joints that aren’t designed to function as the ankle would, and therefore being forced to do the ankle’s job is not in the best interest of the foot. Every foot problem that develops is in some way connected to an ankle joint that isn’t doing its job.  Of course, the ankle not functioning properly can be due to a number of reasons, many of which were previously outlined in prior posts.

Why wouldn’t the Ankle bend sometimes?

Joints either, a. Can’t bend properly because of arthritis (with or without bone growth that limits mobility, Figure 2) or, b. Joints won’t bend because the muscles that cross the joint won’t allow them to (Figure 3).  Unless there was a significant history of prior ankle fracture or many severe sprains, the arthritis that develops is the result of many years of the ankle NOT being allowed to bend the way it was designed to bend.

Figure 2: (Arthritic ankle) This X ray image shows bone built up in front of the ankle and stopping all motion (from the ankle) beyond this point.  All remaining motion must be obtained from elsewhere (middle of the foot, hip, low back or combination of each?).  Point to consider; how does this patient properly walk down stairs if this is the most they can bend their ankle?

Figure 3: (Flat foot) with an Ankle that won’t bend because of motion occurring in the wrong joints.  In this figure, the motion is taken up by the joints in the middle of the foot, just in front of where the “break in the line” is seen.  When you can’t draw a straight line through this column of the foot, then motion won’t occur at the ankle.

 So What’s Next?

Once we understand that an ankle not bending as it should increases the strain and load through the foot, it would stand to reason that by improving the ability of the ankle to bend will in turn reduce the strain and load through the foot, and improve symptoms if they exist.  Therefore, anything that improves ankle mobility is a good thing.  Stretching and mobilizing joints have very short lived benefits, and therefore, something more lasting and sustainable is needed.  What’s needed is going back to the basics of core engagement, postural stability and good movement patterns and habits to allow motion to occur as it should.  It may require some digging to understand why the ankle isn’t bending properly, but it will require work on the patients’ part to get it moving, and most important, keep it moving.  That is what will keep you moving!