Slice geometry: 2nd moment of area


I was wondering if someone can please help me out. Slice geometry’s output via Bonej gives 2nd moment of area about a major and minor axis or Imin and Imax, respectively. Can someone please tell me what is the difference between these two different outputs for 2nd moment of area?

Many thanks,


There is a dearth of clear information on this topic, and some descriptions swap the labels compared to how BoneJ uses them (i.e. the subscript max would relate to the longer axis and the smaller moment, rather than the shorter axis and the larger moment, as BoneJ has used it).

The descriptions elsewhere clarify things somewhat. It would be possible to stick to a convention that the subscript always relates to the axis and not the moment, (i.e. around rather than in the direction of). That would require a review of the code and docs to make sure it all lines up consistently (which I had a go at, here). In the meantime, if you are not sure, it’s worth running the code and seeing empirically whether the result agrees with what you expect or if there is a labelling error on the axes.