HSPCs within the metaphysis exist in an endosteal niche. (A) Micro-CT image of the distal region of a murine femur, revealing the dense interconnecting network of trabeculae. (B) Montage of a toluidine blue-stained paraffin wax section of the distal metaphysis of the exact same murine femur as in the adjacent micro-CT image after histologic processing. The trabeculae are delineated in red using Metamorph software and appear more sparsely distributed than in the more detailed 3D micro-CT image. (A-B) The growth plate is delineated by the dashed line. Above the growth plate is the metaphysis, and below the growth plate is the epiphysis. Scale bar represents 1 mm. (C) Analysis of micro-CT 3D images reveals the distance separating trabeculae. The 12 data points represent individual measurements from the proximal and distal metaphysis from 6 mice. Data are mean ± SEM.