Where is the tape measure placed when measuring the circumference of the head?

Where is the tape measure placed when measuring the circumference of the head?

• A. Where the tape measure naturally lies with the patient's head shape
• B. At all 10% up-markings on the head starting and ending at FPz
• C. Right above the ears
• D. At the inion and nasion

Answer: (B)

Measuring head circumference in EEG setup uses a fixed starting point and uniform spacing around the entire head so electrode positions line up with the 10-20 system. You wrap a flexible tape around the head, placing it flat and snug, and begin at a fixed frontal midline point on the scalp (FPz). Then you go all the way around the head and bring the tape back to FPz, recording markings at every 10% of the circumference. This gives you a reproducible, evenly spaced reference so locations like Fz, Cz, Pz, Oz, etc., align consistently with the standard landmarks. Starting at FPz anchors the measurement to the frontal midline, ensuring the circular distribution of landmarks corresponds to the 10% increments used by the system. This is why the tape is marked at each 10% around the head and why the measurement ends where it started. It isn’t based on a random point on the scalp, nor is it limited to the area above the ears, and it isn’t the same as tracing from nasion to inion along the midline, which is a different measurement.

Measuring head circumference in EEG setup uses a fixed starting point and uniform spacing around the entire head so electrode positions line up with the 10-20 system. You wrap a flexible tape around the head, placing it flat and snug, and begin at a fixed frontal midline point on the scalp (FPz). Then you go all the way around the head and bring the tape back to FPz, recording markings at every 10% of the circumference. This gives you a reproducible, evenly spaced reference so locations like Fz, Cz, Pz, Oz, etc., align consistently with the standard landmarks.

Starting at FPz anchors the measurement to the frontal midline, ensuring the circular distribution of landmarks corresponds to the 10% increments used by the system. This is why the tape is marked at each 10% around the head and why the measurement ends where it started. It isn’t based on a random point on the scalp, nor is it limited to the area above the ears, and it isn’t the same as tracing from nasion to inion along the midline, which is a different measurement.