To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Movie 3 A series of sagittal slices through an E16.5 mouse foetus stained with 0.1% ruthenium red in 50% ethanol and imaged using a 60kVp/133μA X-ray spectrum, displayed using the cartilage window (400-900HU). Development ; doi: 10.1242/dev.187633 Download Original Video