What is the best way to convert a mesh surface region into a solid region?
For example, we can obtain a mesh region of the surface of the left femur as follows.
lf=DiscretizeGraphics[Entity["AnatomicalStructure", "LeftFemur"]["Graphics3D"]]; SolidRegionQ[lf] (*False*) Area[lf] (*61 317.9*) Volume[lf] (*0*)