|What a good boy!|
The thumb carpometacarpal (CMC) joint is a saddle joint. It is capable of 360 degrees of circumduction, as well as abduction, adduction, extension and flexion. It is crucial to good grasp, and essential to pinch. Like the shoulder, it is not solely dependent upon bony congruity for stability, relying significantly upon a network of soft tissue structures. When these structures fail, the stability of the thumb's base is threatened and daily function, let alone sporting function, is significantly impacted.
|Not Ivy, but can you see how the downward pressure|
of the bar could force the metacarpal anteriorly?
I see this most usually in older patients who have degenerative osteoarthritis of that CMC joint. Today I saw it in a young, female elite power lifter. At the top of the snatch move apparently, good form combined with normal shoulder bio-mechanics, dictates that the bar with all its weight, rest not in the palm transferring weight down through the arm, but across the first web space.
I did two things, well three really. The first was that I let Ivy educate me in the technique she uses to lift. We then broke down the mechanics of that, and I applied my understanding of anatomy. Based on that, I could explain to Ivy exactly what I felt was happening and why.
The second thing I did was to splint and tape the hand to provide the CMC with the support it was currently lacking. I didn't want a rigid material, so I used a flexible thermoplastic promoted with the potential to enhance joint proprioception. Whether it does or not, an impressive sentence like that is worthy of its' own blog! I then taped in such a way that the CMC had solid AP pressure. Immediately Ivy had relief.
|Needs dynamic stability training ASAP.|
Might need an opposable thumb first.
Look after those fingers,
O'Brien, V., Giveans, M. Effects of a dynamic stability approach in conservative intervention
of the carpometacarpal joint of the thumb: A retrospective study. Journal of Hand therapy (26) 2013 44-52.