Movie S4.

FIB-SEM images (SE) and 3D reconstruction of a small, fully mineralized distal tendon region in transverse profile to the longitudinal direction of the tissue prepared by protocol 3. The movie shows numerous dark pores of various sizes and shapes throughout the ECM. These pores, reconstructed in 3D, comprise a vast system of secondary channels (turquoise) interconnected and oriented in a perpendicular direction to canaliculi (gold) and directed parallel to mineralized (white) collagen fibrils and fibril bundles.