When creating your own medical instruction, I would like to suggest that you consider prebuilt anatomical models. These vendors have extremely reasonable prices for anatomical models in 3D Studio and Maya, among others.
Turbo Squid
Brain
Anatomy
Anatomical Male
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Extremely High End Quality Medical Illustration
Argosy Medical
Exellent Broadcast Quality Anatomy
Xavier Studio
Medical Illustrators Resource Book
Medical Image Databases Online