Abnormal Chick Embryo (IMAGE) Thayer School of Engineering at Dartmouth Caption In an abnormal chick embryo, the heart loops to the left-hand side and the brain also turn leftwards, forming a shape that resembles a question mark. In a normal embryo the opposite is true, i.e., the heart loops to the right-hand side and the brain also turn right. In previous work, we identified the source and magnitude of the physical force necessary to make the brain twist and discovered that the heart looping direction mechanically determines the brain twisting direction. Credit Dartmouth Engineering Usage Restrictions Dartmouth Engineering 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.