It is characterised by reduction in bone mass per unit volume to a level below that required for adaquate mechanical support.There is no abnormality in ratio of the mineral to organic phase of bone matrix. It is also defined as bone density that fall 2.5 standard deviation below the mean for that population. Causes 1 nutritional n git disorders malnutrition,malabsorption syndrome,severe liver disease. 2 endocrine disorder Cushing syndrome,thyrotoxicosis. 3 inherited disorder,osteogenesis imperfecta,marfan syndrome,porphyria. 4 drugs chronic steroid therapy. 5 rheumatoid arthritis,ankylosing spondylitis Clinical features Fracture is only cause of symptoms in osteoporosis which produce sudden pain.Common site of fracture include spine,hip n wrist jt. Lab investigations 1 Sr calcium,alkaline phosphatase,urine calcium. 2 urinary lever of cross linked N-telopeptide of type 1 collagen more than 40nmol/L indicate excessive bone turnover n is feature of osteoporosis. 3 radiograph of spine n pelvis. reduce cortical thickness of bones,increase radioluscency of bone.Vertebra show Codfish appearance. 4 measurement of bone density by ct scan,ultrasound n DEXA scan. Treatment 1 diet should include at least 1 g of calcium n 400-800 IU of vit D. 2 ensure adequate wt bearing exercises. 3 smoking n alcohol should be stopped 4 reduce fall by taking care of home safety n personal precautions. 5 if steroids r required for chronic use,addition of calcium, vit D n bisphonates.