In the 10-20 system, the sagittal and coronal planes are divided at what percentage?

In the 10-20 system, which is commonly used for electrode placement in electroencephalography (EEG) and other neurophysiological studies, the landmarks on the scalp are defined based on specific percentages of the total distance between certain anatomical points. This system divides the head into standardized areas to ensure proper and consistent placement of electrodes.

The division at 20% refers specifically to the placement of electrodes along the coronal and sagittal planes, which align with recognizable anatomical landmarks. The distances measured from the nasion (the bridge of the nose) to the inion (the bony prominence at the back of the skull) help establish these locations. In the 10-20 system, the interelectrode distances are thus defined to be 10% and 20% of these total distances.

When considering the sagittal and coronal planes, the 20% division is significant as it establishes the positioning of electrodes that are essential for optimal recordings in sleep studies and other neurological evaluations. This percentage is critical for aligning electrodes accurately in relation to cerebral functional areas, ensuring effective monitoring and diagnosis of various sleep disorders.

The other percentage choices do not align with the established standards of the 10-20 electrode placement system for defining these