Figure 36: The wall of a socket (tooth is in place in the upper left corner) shows almost all bone cells or osteocytes to be missing or considerably shrunken (pyknotic).  The dead cells leave behind white or clear oval spaces, as seen here.  This is a sign of necrosis of the bone, but the pathologist must be cautious because caustic acids used to decalcify bone in the laboratory may destroy the osteocytes as well.  The bone in this photo was decalcified gently with mild formic acid.  Signs of chronic ischemia include an excess of purple cement or reversl lines and a microcrack along one of the lines (lower right).