The skull has been sliced in half down the centre, revealing details of the internal structures. These include the delicate bones and spaces of the paranasal sinuses (around the nose and eyes, centre left), as well as the fused bones of the cranium that encase and protect the brain. The nasal, cheek and upper jaw bones are shown fused to the cranium to form the facial skeleton (left). The lower jaw bone (mandible, lower left), is attached at flexible joints, allowing it to move.