Dear Andrea:

If you are looking at femoral head sections, remember that the decalcifying 
process is a slow and tedious one.  However, with proper monitoring, the end 
result can be fabulous.  I would recommend FIXING the specimen first in 
formalin (depending on the size of the specimen) at least overnight.  We use 
Surgipath Decal I, and change it every day.  It usually takes at least 4-5 
days to decalcify a femoral head.  Change the solution at least once daily, 
and rinse the specimen daily for at least 30 minutes in tap water (to remove 
calcium salts).  When you finally can cut the specimen, and it is time to 
process, make sure the tissue sections are no more than 2-3 mm thick.  

After processing, embed the specimen diagonally in the mold.  This keeps you 
from "facing" into too much of the specimen at one time.  I cut my blocks on 
the vertical axis of the block holder on the microtome.  After gently facing 
the block, rub a little warm water over the surface and slowly section the 
block.  If it is still too hard, try immersing the block in cold decal 
solution for 10-15 minutes after facing.

We fix bone marrow biopsies in formalin for 2 hours, then in DECAL I solution 
for 30-45 minutes.  RINSE WELL after decalcification.  Results have been 
great.  (Again, I embed the specimen diagonally in the mold.)

I know this is way too long, but bottom line I think the key to good bone 
sectioning is fixation and changing decal solutions periodically.  

Good luck with the bone!

debra flynn
jackson, ms  (sorry this was so long!)  :)