Iliacus Muscle Contusion with Submuscular Haemorrhage

And minor rectus femoris tendon strain/low grade interstitial tear

MRI Appearance of Chronic Stress Injury of the Iliac Crest Apophysis in Adolescent Athletes

http://www.ajronline.org/cgi/content/full/190/6/1487

AJR 2008; 190:1487-1491