Comparisons of periosteum from amputated and non-amputated bone (b: cortical bone, cam: cambium layer of periosteum, fib: fibrous layer of periosteum). (A,B) Matched comparison of the contralateral, non-amputated tibia (A) compared to the amputated tibia (B), from Donor 10. (C) Normal femur (Donor 7), and (D) periosteum from an amputated femur (Donor 11). Of note, cambium cellularity is lower directly adjacent to amputated bone, and layers are more difficult to distinguish (B,D). Scale bar: 100 μm.