per·i·cra·ni·um 
(pĕr′ĭ-krānē-əm)
(pĕr′ĭ-krānē-əm)n. pl. per·i·cra·ni·a (-nē-ə)
The external periosteum that covers the outer surface of the skull.
[New Latin pericrānium, from Greek perikrānion, from neuter of perikrānios, around the skull : peri-, peri- + krānion, cranium; see CRANIUM.]
per′i·crani·al adj.