The axial twist occurs in the early embryo. Shortly after the neurulation, the anterior head region makes a half-turn around the body axis in anti-clockwise direction (looking from tail to head), whereas the rest of the body (except heart and bowels) make a half-turn in clockwise direction. Since the axial twist is located between the ear-region and the forebrain-face-region, it is predicted that the face grows from the left to the midline, as is indeed the case.