Where should lead V5 be placed on a patient?

Lead V5 should be placed at the mid-clavicular line and the 5th intercostal space to accurately monitor the heart's electrical activity from the left lateral aspect. This specific location allows for optimal viewing of the electrical changes occurring in the left side of the heart, which is essential for diagnosing various cardiac conditions, such as ischemia or infarction.

The mid-clavicular line serves as a vertical reference that helps standardize the positioning of the electrode in relation to other leads, while the 5th intercostal space is the appropriate horizontal position, corresponding to the anatomical landmarks of the heart. Accurate placement of lead V5 is crucial, as it provides critical information from a vantage point that is important for assessing the heart's function in clinical settings.