This is something I've studied a lot, because we had a neighbor die years ago, despite our efforts to keep him going until the ambulance arrived. Just to clarify for those who might not check the link:
CPR, cardiopulmonary resuscitation, is the one to use when someone has stopped breathing. That's where you press rhythmically on the center of chest or "sternum" (above the xiphoid process*). For infants, you do it only very delicately, with fingertips instead of hands. As someone mentioned, the recommended method for CPR has changed in the past few years, so it's good to get re-trained on it if you can.
The Heimlich Maneuver is the one to use when someone has something stuck in his throat. In this case, you do not press on the sternum, but on the soft abdomen below the sternum (and below the xiphoid process*), with an upward motion to try to expel air (and the stuck object) from the windpipe.
* The xiphoid process is a small bit of cartilage at the lower end of the sternum, and it's fragile -- so you have to be sure you're above it for CPR and below it for the Heimlich.
CPR, cardiopulmonary resuscitation, is the one to use when someone has stopped breathing. That's where you press rhythmically on the center of chest or "sternum" (above the xiphoid process*). For infants, you do it only very delicately, with fingertips instead of hands. As someone mentioned, the recommended method for CPR has changed in the past few years, so it's good to get re-trained on it if you can.
The Heimlich Maneuver is the one to use when someone has something stuck in his throat. In this case, you do not press on the sternum, but on the soft abdomen below the sternum (and below the xiphoid process*), with an upward motion to try to expel air (and the stuck object) from the windpipe.
* The xiphoid process is a small bit of cartilage at the lower end of the sternum, and it's fragile -- so you have to be sure you're above it for CPR and below it for the Heimlich.