Need Help with STL for Prosthesis

Hello,
I am in the process of designing prosthesis for a woman that lost 9 fingers. This STL is a scan of her left hand. The STL file I uploaded is way too big to open as a solid body in SolidWorks so I need some help making it smaller. If someone would be able to convert this file into an .xt, .step, or .igs, that would be great. Or even if someone could cut it up into smaller sections so I could create an assembly in SW and use the model that way. Thank you for your help.