There is a gradual change in the degree of mineralization across the tendon-to-bone insertion of the rotator cuff as evaluated by Raman spectroscopy (right panel, apatite [960 Δcm−1] to collagen [2940 Δcm−1] peak ratios are plotted relative to position. [Adapted with permission from Wopenka B, Kent A, Pasteris JD, Yoon Y, Thomopoulos S. The Tendon-to-Bone Transition of the Rotator Cuff: A Preliminary Raman Spectroscopic Study Documenting the Gradual Mineralization Across the Insertion in Rat Tissue Samples. Appl Spectrosc. 2008 Dec;62(12):1285–94.]