Shins, then hands. I have impacts on shoulders, thighs, boot, but majority on shins, most serious starting on shins...as to the why? Hands from bracing from impact (yeah, yeah, I know, don't put your hand out, this applies only to preventing my face from eating rock garden)...shins, probably because when you bail/crash and automatically clip out, your shins are closest to the ground/trail detritus.