464 



J. JOWSEY 



Fig. 8. MiLioiacIiograph of a cross section through the teimir of an indi- 

 vidual with hyperparathyroidism, showing recent new bone formation at a, b, 

 and c, and minerahzation of connective tissue in haversian spaces at d, e, and 

 /. Most bone surfaces are in the process of resorption. (X 22.) 



normal. In osteogenesis imperfecta, abnormal levels of both forma- 

 tion and resorption contribute toward the decreased mass of tissue. 



Rickets 



The microradiographic appearance of rickets is most unusual. The 

 gross appearance (Fig. lOA) is one of porosity with many areas of 

 decreased density; the high-power appearance (Fig. lOB) shows 

 the decreased mineral density of the cement lines surrounding the 

 osteons and the lack of mineral around the osteocytes and their 

 canaliculi. It is the enlarged canaliculi that are mainly responsible 

 for the unusual appearance, and whether this represents incomplete 

 mineralization as the bone is laid down or demineralization and 



