Cranium is the large hollow, rounded part of the skull. Its cavity encloses the brain hence cranium is also called brain box. The dome shape offers more mechanical strength than a flattened surface. The cranium is formed of 8 flattened bones. These include 1 frontal, 2 parietals, 1 occipital, 2 temporals, 1 sphenoid and 1 ethmoid bone.