My weird doctor's visit.

I do not have a cast or a boot on my foot.  They called me after the MRI and I went in yesterday to get one, but they didn't have any.  They said they'd call me and have me come in another day (with no co-pay next time.)  Also, when the doctor was reading the MRI report, she said that I had a tear in the tendon on the outside of my ankle (not the inside where it has been hurting) and that I had an ankle sprain.  I said "Really?" and she said "You haven't sprained your ankle?"  and I haven't, at least not recently.  I did hurt this ankle really bad on my oldest son's second birthday, so 16 years ago.  I wonder if this tear occurred then and they can't tell on the MRI?   I'm starting to wonder if doctors really "know" anything or if it is all 100% educated guessing.  Anyway, at some point, I'm going to be wearing a boot for a little while to see if it helps.  Who knows?