An X-ray showed that Wang's wrist wasn't just broken - the bones were shattered. Tang would need to piece the tiny bone fragments back together like a jigsaw puzzle and hold the mended wrist in place with a metal plate. But something else about Wang's injury bothered Tang.
He probed further into Wang's medical history, and confirmed that she had experienced menopause about 10 years earlier. Menopause results in a dramatic fall in levels of oestrogen and progesterone, a woman's hormones. Among other things, oestrogen plays an important role in stimulating bone formation.
Bone is living tissue - it is constantly replaced by new tissue. When the action of oestrogen is reduced or removed, bone tissue may not form as quickly, or as well. This leads to a decrease in bone density, and results in brittle bones that could shatter in a fall. Given the extent of Wang's injury, Tang suspected that she had osteoporosis, or "porous bone" disease.
To confirm his suspicions, Tang had her undergo a dual-energy X-ray absorptiometry (Dexa) scan to measure her bone density. The painless and non-invasive procedure exposes the body to short bursts of X-ray beams of different energy levels. It then measures how many X-rays are absorbed by the bones, and can detect even early stages of mineral loss from the bones. The level of radiation the scan uses is less than a regular X-ray.
The results are expressed as a T-score. Normal bone density yields a T-score greater than minus one. A T-score of less than minus 2.5 confirms osteoporosis. Wang had a T-score of minus three, which was considered very low.