Lee and Pearson developed an equation for estimating the cranial capacity based on external measurement of the skull dimensions.
Measurements:
(1) maximum cranial length in mm
(2) maximum cranial width/breadth in mm
(3) auricular head height in mm (distance from external acoustic meatus to the vertex)
cranial capacity in cc for a male =
= (0.00337 * ((cranial length) – 11) * ((cranial width) – 11) * ((auricular head height) – 11))) + 406.01 +/- 50 cc
cranial capacity in cc for a female =
= (0.004 * ((cranial length) – 11) * ((cranial width) – 11) * ((auricular head height) – 11))) + 206.06 +/- 50 cc
Limitations:
• 11 is used to compensate for bone thickness (two bones thicknesses each 5.5 mm). Variation in bone thickness could affect the final calculation.
• The cranial capacity for a patient with an abnormal cranial shape might differ from the predicted value.
