Principles of Manual Medicine
Pathologic Barriers to Motion
Pathological barriers to motion can also be found within muscle, skin, fascia, ligaments, and joint capsules. A barrier may involve a single joint or spinal segment, or it may cross over more than one joint or spinal segment. The different pathological changes within these tissues result in loss of motion and/or characteristic endfeel sensations. When a restrictive barrier exists, either the active range of motion is compromised or there is no passive range of motion beyond the active range. When a restrictive barrier is present, the range of active motion is defined by the normal physiologic barrier and the restrictive barrier. The goal of treatment is to move the restrictive barrier as far into the direction of motion loss as is possible.
Remember that structural diagnosis is specifically directed towards the identification of abnormalities in symmetry, range, and quality of joint motion in order to identify dysfunction and treat to restore maximal, pain-free movement of the musculoskeletal system. You will be continually asking yourself the following questions:
- Is the total range of motion symmetric?
- Is the total range of motion reduced from normal?
- What is the quality of the motion?
- What is the characteristic feel at the end point of motion?
- Normal: Smooth, spring-like
- Hypertonic: Tight
- Hypermobile: Little resistance until the very end, hard endfeel
- Fibrotic: Abrupt, hard endfeel
- Spasm: Jerky, guarding caused by pain
- Edema: Boggy, spongy
A phenomenon associated with a restrictive barrier is the shifting of the neutral resting position away from midline neutral. This new resting position is called the pathological neutral and is usually, but not always, at the midpoint of the available range of active motion. Remember that the neutral resting position is a relative term in that it relates to a specific region.
You should be aware of the concept of "ease" and "bind". In the application of functional techniques, the practitioner is interested in the quality of movement. Is the movement easy and free, or is it difficult and binding? The more one moves away from the neutral position, the more one feels a certain amount of bind or increase in resistance to the movement. Likewise, the more one moves toward the neutral position, the more one feels a certain amount of ease or decrease in resistance to the movement. Loose-packed is the term used to describe a joint that has been positioned at the point of maximum ease. Understanding the concept of ease and bind and the ability to sense this phenomenon are essentual to mastering functional (indirect) techniques.
Hypertonicity is a condition of excessive muscle tone that may result in a loss of range of motion because of increased resistance of the muscle to passive stretching. Because of their increased resistance to stretching, hypertonic muscles result in a perceived barrier to normal passive motion. Click here to visualize the tension/displacement characteristics of a hypertonic muscle. Be sure to notice the difference between the force/displacement curve of a normal muscle and a hypertonic muscle. Dysfunction is present when we find that a normal barrier has lost it's normal elasticity, and/or the available range of motion has decreased. The goal of treatment is to move this restrictive barrier as far into the direction of motion loss as is possible.
Restriction of Rotation -- Cervical Example
I am going to use the motion segement of C1/C2 in an example because it relates closely to the illustrations that I have been using for barrier concepts. Under normal circumstances (Click here), equal rotational forces will produce equal rotational displacements.
However, when pathology is present, equal rotational forces will not produce equal displacements. (Click here) to see how a hypertonic left obliquus capitis inferior muscle results in a restrictive barrier to right rotation. If a patient came into your office with this condition you would make a positional diagnosis of C1 rotated left, or you could say that the segment was right rotation restricted. (Click here) to see how a hypertonic right obliquus capitis inferior muscle results in a restrictive barrier to left rotation. If a patient came into your office with this condition you would make a positional diagnosis of C1 rotated right, or you could say that the segment was left rotation restricted.
Restriction of Flexion -- Lumbar Spine
In the absence of dysfunction, flexion and extension results in symmetric opening and closing of paired facets. When we speak of the capacity of facets to open and close, we are referring primarily to the accordion-type movement that occurs during flexion (forward-bending) and extension (backward-bending), not separation-type movement.
Lets add some muscles to a lumber motion segment. When both muscles are normal (Click here) we see that the facets open and close fully. However, if both muscles are hypertonic, we see that the ability of the facets to fully open is compromised (Click here) to see the simulated effect when both right and left lateral intertransversarius muscles are hypertonic). In terms of the postional diagnosis (remember that the positional diagnosis describes where the structure that we are examining wants to go), we would say that this segment is extended. In terms of the motion restriction diagnosis (remember that the motion restriction diagnosis describes where the structure that we are examining does not want to go), we would say that this segment resists flexion.
Now suppose that the muscle between the left transverse processes is normal and the muscle between the right transverse processes is hypertonic (Click here) to see this visualized when a simulated hypertonic right lateral intertransversarius muscle results in a restrictive barrier to flexion, left rotation, and left sidebending). You can see that both facets are still able to close fully, but only the left facet is able to open fully. The right facet is prevented from opening fully because of the increased tension within the muscle between the right transverse processes. In terms of the postional diagnosis (remember that the positional diagnosis describes where the structure that we are examining wants to go), we would say that this segment is extended, right rotated, and right sidebent. In terms of the motion restriction diagnosis (remember that the motion restriction diagnosis describes where the structure that we are examining does not want to go), we would say that this segment resists flexion, left rotation, and left sidebending.
Now suppose that the muscle between the right transverse processes is normal and the muscle between the left transverse processes is hypertonic (Click here) to see this visualized when a simulated hypertonic left lateral intertransversarius muscle results in a restrictive barrier to flexion, right rotation, and right sidebending. You can see that both facets are still able to close fully, but only the right facet is able to open fully. The left facet is prevented from opening fully because of the increased tension within the muscle between the left transverse processes. In terms of the postional diagnosis, we would say that this segment is extended, left rotated, and left sidebent. In terms of the motion restriction diagnosis, we would say that this segment resists flexion, right rotation, and right sidebending.
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