If the distance from Fpz to Oz is 48 cm, what is the expected distance from Pz to Oz?

To determine the expected distance from Pz to Oz based on a known distance from Fpz to Oz, understanding the spatial relationships within the 10-20 system of electrode positioning in polysomnography is crucial.

In the 10-20 system, the distance between Fpz and Oz is typically divided into standardized proportions when locating other electrodes. Given that the distance from Fpz to Oz is 48 cm, we can use this information to calculate the distances to other points on the head including Pz.

Pz is located approximately at the midpoint between Fpz and Oz. Thus, if Fpz to Oz is 48 cm, the distance from Pz to Oz can be deduced by considering the layout of the electrode positions. The Pz electrode is positioned about one-third of the way down from Fpz to Oz. Therefore, if we calculate one-third of the total distance, this would result in a measure that corresponds to the distance from Pz to Oz.

Performing the calculation:

1/3 of 48 cm equals 16 cm, which represents the distance from Pz to Oz. However, since we are looking for a precise breakdown in the context of the provided options, and based on the standard practices in electrode placement