Noun
microfracture (plural microfractures)
A very small, or fine, fracture, especially one of a series in bone.
Buehler was pulled in the sixth inning when his velocity dropped and underwent further testing including the MRI which revealed the microfracture. Source: Internet
He hasn’t played a full season since he appeared in 163 games in 2008, missing the final 20 games of 2009 because of a microfracture in his lower back. Source: Internet