QL Block (IMAGE) Medical University of South Carolina Caption Nicole McCoy, M.D., uses a needle to perform a QL block on her patient prior to bone marrow harvesting. Credit Brennan Wesley, Medical University of South Carolina Usage Restrictions May be used with appropriate credit. License Original 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.