Fig. 2From: Changes in viscoelastic properties of articular cartilage in early stage of osteoarthritis, as determined by optical coherence tomography-based strain rate tomographyOptical coherence tomography (OCT) image of articular cartilage. The highest signal line, around 300 μm depth, is surface of cartilage. The second highest signal line, around 700 μm depth, is the boundary between non-calcified cartilage and calcified cartilage (tidemark)Back to article page