I know of one guy who has had many injuries from practicing aikido. In fact, he has had far more injuries from training than anyone I know. Let's see...he has had:
Two dislocated toes. (He also tore the skin between the toes when he dislocated them)
Torn right hamstring. (Got caught in a hakama)
Torn right ankle tendons. (Rolled his foot over running behind nage for an attack)
Torn left knee tendons. (Weakened by marathon running)
Torn right rotator cuff tendons. (Too hard nikkyo osae)
Fractured left elbow. (Shihonage, I think)
I wonder what his answer would be to the question, "What is the most common injury in your dojo?"