418 



URIST, MACDONALD, MOSS, AND SKOOG 



100 ^0.3 

 90_ 



80. 



70. 



5 60. 



50. 

 40 

 30. 

 20. 



lOj 

 0, 



_0.2 



_0.l 



CASE _._^ 

 NO. 7 CASE 

 No. 8 



• 29 RANDOM AUTOPSY SUBJECTS 

 (LINDAHL AND LINDGREN, 1962 ) 



X 7 OSTEOPOROTIC PATIENTS 

 (URlST et Ql.,1962) 



10 20 30 



40 50 



AGE 



~~i 1 1 1— 



60 70 80 90 



100 



Fig. 12. Graph illustrating relation between change in bone density and 

 age in random autopsy subjects and in patients with severe osteoporosis. The 

 amount of retention and the rate of change in bone mass after age 70 is almost 

 the same in the two groups of white women. The important characteristic of 

 the group with severe osteoporosis is the sudden change in the quantity of 

 bone retained in the skeleton between 50 and 65 years of age. The chief feature 

 distinguishing the osteoporotic group from the group with physiologic rate 

 of decrease in bone mass or aging was bone failure, or spontaneous collapse 

 of vertebral bodies. It was assumed that borderline cases of osteoporosis, with 

 or without slight bone failure, could occur in older age groups, but the separa- 

 tion of the two groups was generally quite clear-cut. 



cularized and resorbed too fast to be replaced by new bone (Figs. 

 13A to 13C). 



Recent and Related Literature 



Race, Sex, and Genetic Factors 



Moon and Urist (1962) reported 87 cases, 77 women and 10 men, 

 with severe osteoporosis admitted to a new hospital that received 

 90,000 patients over a period of 4 years. All were Caucasian. Trotter 

 et al. (1960) measured the density of whole bones of anatomical 

 specimens by the ratio of weight to displacement volume and ob- 



