Deeper muscle fibers closer to the joints stabilize the joint more than move it (intrinsic); more superficial muscle fibers move bones around the joints more than stabilize them (extrinsic)
I read somewhere in my research when a person is under a general anesthetic that all the skeletal muscles in the body completely turn off and have no tone in them. Under that circumstance, the bones are hanging in the joints by ligaments and joint capsules. Furthermore under that circumstance, an average 12-year old child could dislocate any joint in the body with a good tug, even L-5/ S-1. That is how little joint stability comes from ligaments and joint capsules, and how much joint stability comes from muscle tone.
The body must be stable before it moves or joints would dislocate. You can probably see that in these terms we are an intrinsic/extrinsic phenomenon: before we move our bodies (extrinsic firing of movement muscle patterns) we stabilize our joints (intrinsic firing of joint-stabilizing muscle patterns). If a 12-year old child can dislocate my low back joints, I must stabilize my low back before I get out of a chair, or else I would dislocate low back joints.
Therefore, kinesiology does not describe our movement; we are not a pattern-based blend of origin-insertion-action muscle organization. We are organized by patterns of intrinsic ‘lines of force’ (muscle tones) stabilizing our joints just before patterns of extrinsic ‘lines of force’ move us; our intrinsic lines of force support and stabilize our extrinsic movements. We always stabilize before we move.
In terms of tensegrity and remaining upright and stabile, movement on one side of the body (e.g., picking up a glass) must be stabilized on the opposite side of the balance line (the spine). Also, since a triangle is the most stable structure, the body will intrinsically stabilize this movement above and below the lines of force that the movement feeds into the structure. So for our example, picking up a glass, just before I pick up the glass with my right hand the deep intrinsic muscle fibers on the left side of my mid-neck will fire in the amount of force it takes to stabilize my spine and keep me upright. This would tilt my head to the left, and that is balanced by muscle fibers firing around occiput/C1/C2 on the right side of my neck. You can see how the entire movement is supported and stabilized in a triangular pattern organization.
This is also happening below the lines of force of the movement on the left side of the spine and dissipates into the spine/rib cage on its way through the sacroiliac joints and then to earth.
The same organizational phenomenon happens in response to hypertonicities as it does to movements, so a hypertonicity in the right shoulder and/or traps gets stabilized in the same way. No hypertonicity in the body exists by itself; it must be stabilized by an intrinsic pattern. Thus, for effective bodywork, addressing and affecting the intrinsic pattern must accompany work on the extrinsic expression of the client’s presenting problems.
As an example let’s say a client presents with pain in the right arm/shoulder and I suspect anterior rotator cuff damage, pretty much confirmed by assessing palpation and range of motion restrictions. In addition to local massage work on adhesions and/or scar tissue around the gleno-humeral area, it will serve me well to palpate and assess the left mid-neck ‘myofascial scene’, especially deep around the vertebrae. In the same sense, working the right sub-occipitals will support effective work. Feeding the right arm/shoulder into the rib cage and through the SI joints helps ensure that my rotator cuff work will be more effective and long-lasting.
Additionally, affecting the intrinsic support and stability patterns will affect the extrinsic problem and problematic pattern, making it easier to be effective. Conversely, working on the extrinsic manifestations of the cause/result of chronic pain and function issues will not necessarily affect the intrinsic support and stability patterns. This is arguably the case when I find my work is effective in the short term but does not last, as the intrinsic support and stability pattern will make it easy for the problem to return or reoccur.
I have found this to very often be the case in my work: If I address the intrinsic support and stability patterns for a given client issue, the work I do at the extrinsic site will be much easier to the point that, often, a good ‘tune-up’ to loosen the tissue and increase local blood flow is all that is required. I have had long-lasting results with clients when taking intrinsic patterns into my therapy considerations.
The short of this idea is look for the intrinsic triangles that support and stabilize the hypertonicities of chronic pain and problems. They will be in a pattern close to the skeleton and above and below the hypertonicities on the opposite side of the spine. There is no limit to how they can be combined and worked to serve you and your client.