Wiktionary
endocast
n. A cast made of the mould formed by the impression the brain makes on the inside of the neurocranium, providing a replica of the brain with most of the details of its outer surface.
Wikipedia
Endocast
An endocast is the internal cast of a hollow object, often referring to the cranial vault in the study of brain development in humans and other organisms. Endocasts can be artificially made for examining the properties of a hollow, inaccessible space, or they may occur naturally through fossilization.
Usage examples of "endocast".
But ideas on the antiquity of language have received a measure of unexpected support from detailed studies of fossil endocasts made by the American anthropologist Ralph L.
It might be very illuminating to examine fossil endocasts of their braincases.