The length of the face may be measured from the ophryon or nasion to the chin, or, if the mandible be wanting, to the alveolar point; while its width is represented by the distance between the zygomatic arches.    From Wordnik.com.  [II. Osteology. 5d. The Interior of the Skull] Reference

The horizontal circumference of the cranium is measured in a plane passing through the glabella (Turner) or the ophryon (Flower) in front, and the occipital point behind; it averages about 50 cm. in the female and 52.5 cm. in the male.    From Wordnik.com.  [II. Osteology. 5d. The Interior of the Skull] Reference