Fig. 4.

a–c Selected axial slices (inferior to superior) on bone windows from the head CT examination in the same infant as Fig. 3 which demonstrate a cortical irregularity involving the right occipital bone (white arrows), suggestive of a fracture. However, there is no associated soft tissue swelling and on the 3D reconstruction (d); the cortical irregularity is curvilinear in appearance rather than linear, the latter being more typical of a fracture. The location, adjacent to the lambdoid suture, its appearance, and the absence of soft tissue swelling suggest this is more in keeping with an accessory lambdoid suture (black arrows)