Ovariectomy decreased trabecular BMD whereas arthritis decreased both trabecular and cortical BMD. Peripheral quantitative computer tomography (pQCT) was performed to measure trabecular and cortical bone mineral density (BMD). (a) Trabecular bone mineral density (BMD) was determined with a metaphyseal scan at a point 3% of the length of the femur from the growth plate and the inner 45% of the area was defined as the trabecular bone compartment. (b) Cortical BMD of the femur was determined with a mid-diaphyseal scan. Results are shown as box plots (values are given as medians (horizontal lines), interquartile ranges (box) and ranges (whiskers); circles represent outliers). For controls, n = 10 for sham (open boxes) and ovariectomy (filled boxes); for immunized mice, n = 18 for sham and n = 14 for ovariectomy. **P < 0.01; ***P < 0.001. CII, type II collagen.