Geodesic Sensor Net - Net Size; Vertex Point

6: Applying the GSN
61
Geodesic Sensor Net Technical Manual S-MAN-200-GSNR-001 • January 31, 2007
Adult size ranges for the HCGSN are:
• small (54–56 cm.)
• medium (56–58 cm.)
• large (more than 58 cm.)
To perform this measurement:
1 Ask the subject to use his or her index finger to secure one end of the measuring
tape to the glabella.
2 Run the tape along the side of the head, above the ear, toward the back and
2.5 cm. (1 in.) above the inion, around the other side and above the other ear,
and back to the glabella.
Vertex Point
The vertex , on the top of the head, is the midpoint between the nasion (the indented
area where the bridge of the nose meets the skull) and
inion , centered between the
preauricular points (the indented area in front of each ear flap, where the jaw meets the
skull); see Figure 6-2. The vertex is also called the
Cz in the international 10-20 system.
Figure 6-2. Skull landmarks
Preauricular
point
Gray’s Anatomy
Nasion
Inion
Preauricular
point
Distance between
the nasion and
the inion
Distance between the
preauricular points
Vertex
(intersection of the preauricular midpoint and the nasion–inion midpoint)