From cranio- + -scopy.

cranioscopy

1. (rare) The study of the shape, size, and other features of the human skull.
   • 1864, C. G. Carus, “Some Remarks on the Construction of the Upper Jaw of the Skull of a Greenlander,”, in Journal of the Anthropological Society of London, volume 2, page cxiv:

     In the first part of my Atlas on Cranioscopy, which appeared in Leipzig in 1843, I remarked that in the skull of a Greenlander, which I sketched, it was singular, that on this skull there was a decided separation between the upper jaw-bone and the intermaxillary bone, almost as in little children or in quadrupeds.

2. (dated) Phrenology.