Original AnyBody shoulder bone geometries

Hi guys,

The geometries used in the shoulder model (scapula + humerus) are quite coarse. Do you have the original scans (STL) ? I would like to use them in a cad software to place implants on them.

Thank you.

Pierre

Hi Pierre,

I’m sorry to say that we don’t have the original scan file of the scapula and humerus.
So we can’t provide them to you.

Sorry again.

Best regards,
Moonki

Hi Moonki,

No problem there ! Do you know from where the geometries come from ? Does all the body comes from a unique specimen ? Does the geometries were obtained from a CT-scan or a MRI ?

Thank you.

Pierre

Hi Pierre,

The models are developed over the past 10 years or so, and the sources for the various bones are not clear anymore. Also, they have been stretched and morphed to fit each other reasonably. I think there are two ways to get a model with a finer surface mesh:

  1. Use a free utility called Meshlab to refine the mesh of the existing models. Meshlab is remarkably good at it, but the surface you create will of course be an artifact.

  2. Try to get a scanned bone from another source and use it instead of the standard bone.

Best regards,
John

Hi John,

Thanks for the info ! I always had the impression that some bones were stretched (e.g scapula). I previously tried to use bones from another source. However, it is a long journey because you have to fit the new bone on the existing model, and then you realize that there are large anatomical differences. Thus, you also have to change the muscles origins and insertions.

I know Meshlab well. Here we use Catia v5 because it can do a lot more than Meshlab. I was previously talking with Mr. Nolte and he also told me to refine my mesh. Sometimes, refining the bone gives strange errors (degenerate triangles on master surface: xxxxx. Please check STL file). What does it means and how can I avoid it ?

Also, which theory did you use for the AnyForceSurfaceContact. There are a lot of literature information on master vs. slave surfaces. There are rules to determine which geometry should be defined as the master (e.g. master = rigid surface, slave = softer material and more finely meshed).

At first, I chose the scapula as the master surface and I got the degenerate triangles error. If I choose the humerus as the master surface, I don’t have this error anymore.

Moreover, I think that if one side of the joint is significantly harder than the other side, the penetration should occur on one the softer side only. Thus, If I simulate a prosthesis on the humerus (hard material) and none on the scapula (soft bone material), should I switch the SingleSidedOnOff to On ?

Regards.

Pierre