What is a biomechanical model?

The study of biomechanics is a subfield of biology concerned with understanding the structure, function, and motion generated by the body. With that in mind, a biomechanical model is a representation of the structure, function, and motion of some part of a body or other biological structure.

Below, I have files and instructions on how to construct your own biomechanical model of a human and/or chimpanzee forearm, including the extrinsic (entering the hand from outside the hand) muscles of the forearm. I developed the original models out of balsa wood (as seen in the instructions) for my Scientist Is In events at the Smithsonian Museum of Natural History in 2024. After finding that the balsa wood can't quite withstand the wear-and-tear of a hundred kindergartners, I updated the material to 3D printed plastic (downloadable .stl files below).

Have a 3D printer? Skip gluing balsa wood!

I've created digital 3D files (.stl) for most of the parts needed to make these models. I recommend printing the fingers file twice (to include the thumb and to have back-ups in case of an imperfect print) and printing the spool twice if you're making a human arm with a separate flexor pollicis longus muscle.

• Forearm (without ulna-carpus contact)

• Fingers

• Spool