Regardless of age or sex, the skeletal system can be broken down into two parts, known as the axial skeleton and the appendicular skeleton. Axial skeleton anatomy. The adult axial skeleton ...

The axial skeleton totals 80 bones, consisting of the vertebral column, the rib cage and the skull. The appendicular skeleton totals 126 bones, consisting of the pectoral girdles, the upper limbs ...

This would imply that if 1000 women had appendicular ultrasound measured and 800 were normal (ie, T-score > -2.5), perhaps 200-400 of these would have osteoporosis if they had hip BMD assessed.