Starting in the supine position, the baby is pulled by the arms to the sitting position. The head and the arms are observed during the maneuver. The arms should remain partially flexed at the elbow and the head may lag behind the trunk. When the baby is in the sitting position, the head should be able to come to the upright position for at least a few seconds before dropping forward or backward. Watch the sternocleidomastoid muscles which should bilaterally anticipate the pull to sit; the head flexes for a moment before head lag occurs.