(a) An image of the segmented LCN showing, indicated by a white arrow, approx. (10 × 20 × 40) μm3 region with absent canaliculi, surrounded by isolated, disconnected lacunae, in an example from the GIO group; (b) a tomogram slice in this region confirms the absence of canaliculi, with a featureless matrix region highlighted by a white arrow; (c) shows another GIO group sample with a region containing no canaliculi. The white scale bar in each image represents 10 μm.