Head of a Femur (IMAGE) Columbia University Irving Medical Center Caption This is a schematic of the head of a femur (the thigh bone), showing OCR stem cells in red and the growth of bone (green), cartilage and stromal cells. Credit Mike Barnett for Columbia University Medical Center Usage Restrictions None License Licensed content 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.