Final answer:
For chest compressions during CPR on an adult, place your hands on the lower half of the sternum at the nipple line, between the T4 and T9 vertebrae, to ensure effective blood flow and minimize the risk of injury.
Step-by-step explanation:
When performing chest compressions during cardiopulmonary resuscitation (CPR) on an adult victim, it is critical to place your hands correctly on the victim's chest to ensure efficient blood flow through the heart and to avoid causing injury. The correct hand placement for chest compressions in CPR is on the lower half of the sternum, at the nipple line. This corresponds with the area on the sternum between the lines at T4 and T9 vertebrae. By applying pressure to the sternum here, the blood within the heart will be squeezed out and into circulation. It's important to avoid placing the hands too low on the sternum to prevent driving the xiphoid process into the liver, which can be fatal.