Macrophages on the bone surface

This figure shows the bone marrow space, with large F4/80-positive cells spread out in the centre of haematopoietic islands. At the right of the section, the cortical bone has been sectioned at right angles. The F4/80-positive macrophages can be seen spread in the plane of the bone surface, within the osteoblast layers. The cells regulate the process of calcification by osteoblasts (Chang et al. J.Immunol 2008, 181:1232-1244)