Air pocket under skin?
For awhile now, at least a year or two, I've had what appears to be a pocket of air trapped beneath the skin on my right leg next to my shin. The pocket is pretty much invisible when my leg is relaxed but becomes much more pronounced when my right calf muscle is tensed up for any reason. The area isn't painful and there isn't any reason to believe that it's anything especially serious, but you can never be too careful. For my own knowledge's sake I'd like to know what this could be. Any info or ideas would definitely be appreciated.