Speaking of Numbness

My left leg has been numb for the last couple of days, and it's really bothering me. The numbness is spread from halfway down my back all the way down to my toes. It feels like it was dipped in Novocaine.

This has happened to me before. About a year ago, and I went to the doctor but he said it was probably a weird random thing. I was worried about MS, and I wanted to have an MRI (because I'm a hypochondriac), but he watched me walk around, and then declared that it wasn't necessary. Since then, I get littler patches on numbness intermittently around my legs, but it's not a big deal.

I do have to admit that it made for a very easy leg shaving session in the shower. I didn't feel a thing! Seriously, though. It's disconcerting. What gives, leg!?!?!?