During a witnessed cardiac arrest, where is the precordial thump given?

The precordial thump is a technique used in certain emergency situations, specifically during a witnessed cardiac arrest, to attempt to restore a normal heart rhythm in a patient who is in ventricular fibrillation or pulseless ventricular tachycardia. The correct placement for delivering a precordial thump is at the midsternum, which is the center of the chest. This location is chosen because it allows the energy generated from the thump to be effectively transmitted to the heart, maximizing the chances of converting an abnormal heart rhythm back to a normal rhythm.

Applying the thump at the midsternum facilitates direct impact on the heart, and its effectiveness is based largely on the principle of providing a brief and forceful mechanical jolt. Other locations, such as the left or right side of the chest or below the rib cage, would likely be less effective. The heart sits in the center of the thoracic cavity, and any force applied at the sternum is more likely to affect it positively.