X-Ray Video of Double Kneecap (video) Society for Experimental Biology Share Print E-Mail Loading video... Caption An X-ray video shows the movement of the double-kneecap inside an ostrich leg. Credit Ms Sophie Regnault Usage Restrictions Video only to be used with credit. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.