Hi there, and welcome to the forum!! Although I am not a competitive swimmer, I do, or did rather, enjoy swimming laps nearly every day. Until, I developed the same symptoms that you're describing. Please go to the introductions thread (last page) and read my story. I did not have nerve involvement so much, however, I did also have numbness in my ring and pinky finger, the bottom of my hand and wrist, etc. Then over time, it seemed that the numbness encompassed my entire left hand.

Lo and behold, I have arterial TOS. My left subclavian artery was 100% compressed when my left arm is raised over 90 degrees in any direction. Hence, why I sold my motorcycle- think about how the arms are positioned on the handlebars, why I sold my manual car (couldn't use my left arm comfortably enough to hold the steering wheel while shifting with the right hand..) and why swimming, painting, doing my hair and just about any other activity that raised my arm became so incredibly combersome. Come to find out further, I have the exact same condition on the right side as well. Go figure, surgery will be next year if I can hold out that long.

I am now just over two weeks post op and doing wonderful. They cut out over half of my scalene muscles and 2/3 of my left first rib. Turns out my ulnar nerve was wrapped up in my median scalene muscle. my rib, clavical and scalene muscles were cutting off my artery AND my subclavian veins. For the first time in a very LONG time, I have a PULSE in my left wrist when my arm is up at 180 degrees. Amazing.

TOS is common in swimmers, ball players and folks with either bad posture or folks with a nasty combination of the above. Many who have TOS have a cervical rib as well. I didn't. As I mentioned, I'm no longer an athlete, though I am on top of my game in terms of fitness. Before surgery, ANY repetative motion set off the symptoms.

Get it looked at and go from there. We're all here to help, so ask questions!

Good luck,
Jocelyn