Singh index Singh index is a semi-quantitative morphological index for determining proximal femoral bone loss on X-ray plain radiographs. Singh classifies proximal femoral trabecular changes into 6 levels according to the order and degree of trabecular disappearance, i.e. Singh index: (1) Level 6: intact femoral neck tension and pressure trabeculae; (2) Level 5: disappearance of femoral neck hypotonic trabeculae and reduced density of hypotonic trabeculae; ( (3) Grade 4: disappearance of secondary pressure trabeculae and partial disappearance of primary pressure trabeculae on the basis of grade 5; (4) Grade 3: reduced and interrupted primary pressure trabeculae on the basis of grade 4; (5) Grade 2: disappearance of primary pressure trabeculae and reduced and interrupted primary pressure trabeculae on the basis of grade 3; (6) Grade 1: only part of the primary pressure trabeculae remained. (2) The thickness of the cortical bone of the middle part of the second metacarpal stem should be at least half of the diameter of the area under normal circumstances. 3, Nosland-Cameson single-photon absorptiometry with 1251 as the source of single-energy photons according to the difference between bone tissue and soft tissue absorption photons, can determine the content of bone tissue in the limb, to radius for example, under normal conditions, the proximal epiphysis of the radius is 95% cortical bone, 5% cancellous bone; while the distal epiphysis is 75% cortical bone 25% cancellous bone. Recently, two-photon absorptiometry has also been used, which can distinguish the difference between fatty tissue and soft tissue components within the bone. 4, dual-energy quantitative CT scan quantitative CT scan can distinguish between fatty soft tissue and bone tissue, while dual-energy quantitative CT scan can also distinguish the soft tissue component (bone marrow) in bone tissue. 5.In vivo neutron activation analysis uses high-energy neutrons to activate calcium in the body from Ca48 to Ca49 to determine the decline in Ca48 by r-ray counter, because 99% of calcium in the body is stored in the bone, so it is extremely correct to determine whether the total amount of bone tissue has decreased by this method. 6, iliac bone tissue biopsy in three steps: (1) the first step of 750 mg of oral tetracycline daily for 3 days to mark the bone tissue; (2) 3 days later to take the iliac bone for biopsy; (3) remove the bone block, not decalcified, ultrathin section (5-10μ) for morphological measurements after this method is not suitable for routine examination.