Definition:

A composite-standard is a single cephalometric "tracing" produced manually or by computer analysis which presents visually the "averaged" grouped skeletal configuration and standard deviation of the cephalometric end points of the individuals who comprise the group.

Point Sella is the center, (origin: X= 0.0mm, Y= 0.0mm) of the Cartesian Coordinate system used to describe the position of the cephalometric end-points required to draw and describe the skull and jawbones.

The Krogman-Walker horizontal plane of orientation used to orient the tracings during the digitizing process is defined by the line which connects the point just "below" the key ridge, midway between the superior and inferior cortical plates of the palate, "Maxillon" with the lowest point on the occipital bone "Occipitale".

These standards were created from the digitized tracings of individuals grouped by similar sex and skeletal age as assessed by hand-wrist X-rays, and numbering between 42 and 48 in each group.