Re-defining The Joint: Part 2

This post is intended to supplement my earlier post "Re-defining The Joint: Part" and to continue the journey down the trans-anatomical road of discovery (or re-discovery, to be precise). If you haven't read part 1, I would recommend that you refer to that post before moving on with this one. It will certainly help in the understanding as well as give valuable insight as to what the main message is.

http://thescienceofphysicalrehabilitation.blogspot.com/2011/09/redefining-joint-part-1.html

To briefly summarize, I have proposed a revised definition of a "joint" as: Linear and/or angular displacement between separate biological elements . This definition is more precise and accurate...but it also opens up an entirely new perspective on what actually constitutes a joint. As previously mentioned in my blog, connective tissue has 2 appearances which are seemingly paradoxical: it connects AND disconnects! The connection element is the obvious one (tendons, ligaments, joint capsules, etc) whereas the "disconnection" function is somewhat more counter-intuitive. If you haven't seen Gil Hedley's Integral Anatomy Series videos, then I highly recommend you make a point to watch them. Using standard dissection methods, he intelligently demonstrates the fundamental role of fascia (connective tissue) in SEPARATING body compartments, muscular groups, and systemic organs so that they do not mechanically influence each other. In essense, it allows the elements to "slide" against each other. For example, the liver "articulating" with the diaphragm, deep muscles of the hand (flexor digitorum profundus, for example) sliding underneath the more superficial muscles in the forearm when the fingers are flexed. It doesn't matter whether we actually agree on the definition of a joint...the reality is that without this fundamental characteristic, we would not be able to move...period. We would be as mobile and functional as a Ken (or Barbie) doll..."watered down" to simple hinge joints mixed with a couple of ball and socket joints for good measure.

Therefore, we must add to the understanding and definition of what a joint truly is. This will require some additional qualifying of the term "joint" when making statements or comments. We can consider our typical understanding of joints as SKELETAL ARTICULATIONS...because that's what they are. Therefore, I bring in a new term: FASCIAL ARTICULATIONS.

Each separate colour represents an individual fascial "compartment" and therefore can be considered as a separate biological element. This concept is easily extrapolated into the extremities as well...each individual muscle, muscle group, etc. is compartmentalized as well. It is important to remember that, when we are active (moving), these elements are articulating between each other! Consider a typical tennis swing...with its significant rotational components within the spine. There is a considerable angular displacement between the endothoracic fascia (fascia of the thorax) and the extended fascia of the abdomen (peritoneum). In addition, the follow-through of the arm at the completion of the swing is achievable through, not only the skeletal articulation, but the fascial articulations in the neck (deep, middle, superficial cervical fascia), the shoulder blade (endothoracic fascia), as well as the inter-muscular articulations.

Although it may be difficult to integrate "fascial articulations" into your mental hard drive, it should be easy to understand the obvious role of fascia in human movement...in both connection and disconnection. This provides a "bridge" to a more complete understanding of biomechanics...which is essentially the Trans-anatomical understanding of movement. Fascia is both friend and foe...when it is healthy and strong, you are feeling good. When it is damaged or otherwise unhealthy, it can be your worst enemy. From the most highly conditioned athlete to the the most severely affected child with Cerebral Palsy (who are near and dear to my heart), fascia is THE key fundamental structure in their health, maintenance, and development...period.

I hope the journey to date has been productive...and to those who are still "on the bus", part 3 will go into specifics about trans-anatomical movement and fascial articulations by using an age-old standard test (straight-leg lift) as an example. Hopefully it will engage and enlighten!

Cheers!