Re: Is the pelvis the last bone to ossify, and if so why?

Hi, Molly,


Good question, but there’s no really good answer, I’m afraid. The pelvis 
is the last bone to FINISH the long and slow process of ossification, but 
it’s not the last to BEGIN to be ossified. Ossification of the pelvis 
begins before you’re born, while there are still many bones that haven’t 
even started to become mineralized, like several in your wrist and in 
other places. The pelvis grows a tremendous amount as you reach your final 
size, and it’s big and very complicated. There are bone cells secreting 
bone matrix (mostly made of proteins, especially collagen) right up until 
you finish growing (and afterward, too, during the slow, lifelong process 
of bone remodeling). Bone can only become mineralized after the matrix is 
laid down. While the first phase of mineralization happens fairly quickly –
 within days to a few weeks – at first this mineralization just isn’t as 
dense as it will eventually become. That takes longer, and the pelvis is 
the last bone to reach full mineral density, which is the reason for the 
statement in the previous answer you wrote in about. 

Paul Odgren, PhD
Dept of Cell Biology
University of Massachusetts Medical School
Worcester