pericranium
The membrane (or periosteum) which covers the outer surface of the skull.
After making the incision, the pericranium must be raised a little from the bone with the edge of the knife, to clear the bone, and the scalprum employed.
The head, skull; one's mind.
archaic
Now, Mrs Honour had unluckily poured so much of this liquid fire down her throat, that the smoke of it began to ascend into her pericranium, and blinded the eyes of Reason […]
Where it comes from
From late Latin pericranium, from Hellenistic Ancient Greek περικράνιον (perikránion), noun use of the neuter form of περικράνιος (perikránios, “around the skull”), from περί (perí, “around”) + κρανίον (kraníon, “skull”).
Adapted from the Wiktionary entry pericranium (CC BY-SA 4.0).