Figure 1 From: Cells of the synovium in rheumatoid arthritis. Osteoclasts Osteoclast invading bone. Osteoclasts are multinucleated cells that resorb mineralized tissue. This image shows osteoclasts that have created a resorption lacuna. The cells are stained for tartrate-acid phosphatase (TRAP; top) and for the calcitonin receptor (CT-R; bottom).Back to article page