When I Sit Down And Bend Forward My Left Thumb,index
Compression on nerve roots possible.
Hello dear, welcome to Ask a doctor's service.
I read your query and here is my advice.
I think this can be related possibly to spine issues.
A compression to the spinal nerve roots can cause numbness on arm and leg. Sitting down and moving forward moves the vertebrae and that's why you feel it only while moving spine forward.
I think you should check spine to orthopedic surgeon or rheumatologist for possible start of issues such protruding discs or narrowing spinal canal.
Hope I have answered the question.
Let me know if I can assist you further.