Osteoporosis. X-ray of the hip of an elderly woman with a fracture (centre left) caused by osteoporosis (brittle bone disease). The femur (thigh bone) articulates with the pelvis at the hip socket (centre). Osteoporosis causes a loss in bone density, making the bones thinner, more brittle and more likely to break. In this case the pubis bone of the pelvis was fractured by a fall. Osteoporosis is most common in women after the menopause as their ovaries no longer produce the oestrogen hormones which help to maintain bone mass.