Hello:
  I have run the recon-all command and it finished without errors. The FreeSurfer has generated a stats file  $SUBJECTS_DIR/<subjid>/stats/aseg.stats, there are some information in this file as follows that I can't understand well:

ColHeaders  Index SegId NVoxels Volume_mm3  StructName          normMean   normStdDev  normMin   normMax   normRange 
  1   2    335490   335490.0    Left-Cerebral-White-Matter       109.0668     9.6489    43.0000   183.0000   140.0000

which number corresponding with Volume_mm3?
what does normMean  normStdDev  mean?
what does  Index SegId mean?

thanks in advance                              Tim