Justin LaRoche, a high school student in Virginia, made this project truly "robotic" for a science project. He pulls the "tendons" with servos connected to a computer. If you go to about 5:50 on the video you can see him moving his fingers in a special glove to activate the robot fingers. Amazing!

Check out this wooden-geared robot arm

While researching this section, I learned that there are over 640 muscles in our bodies. Those muscles are attached to bones with tendons

I know that the first reaction of many people is to get grossed out when the subject of surgery comes up. If you can get beyond that, see if you can discern a sense of awe at the engineering of our bodies. Dr. Herbert Ecker kindly took some time to tell me things that only a surgeon specializing in hands would know. When people have catastrophic injuries, including cut tendons, he fixes them. Dr. Ecker told me that tendons are made of living tissue. He compared tendons to multi-ply cotton string. He sews plies of cut tendons back together. If part of a tendon cannot be repaired, it is possible to cut out another tendon that’s redundant (not needed) and sew it in. The new graft will grow its own blood supply. Tendons can heal in as little as 4 or 5 weeks. Of course there’s more to it than that: immobilizing the injury, scar tissue, therapy after the healing to regain range of motion, etc.

Dr. Ecker referred me to a professional organization of hand surgeons. They have some fascinating web pages targeted to the general public. For example, one page addresses the most extreme injury: reattaching a hand or finger that has been completely cut off. Known as “replantation,” delicate surgery not only coaxes bones, blood vessels and tendons to grow back together, but even severed nerves can repair to some extent. You look around the American Society for Surgury of the Hand here.

Medical terminology can seem like a foreign language, and indeed much of it is based on Latin. But invest a little time and you'll get it. For example, "suture" is just a fancy word for "sew." "Intrinsic" hand muscles are located inside the hand and "extrinsic" muscles are the big ones outside in the forearm. "Flexor" pertains to a muscle or tendon that causes flexing or bending, whereas "extensor" refers to muscles or tendons that straighten. "Distal" means "far from," and "proximal" means "close to." Proximal is related to the work approximate.

Here is an interactive site featuring hand anatomy. Click on a muscle in the colored picture, the name pops up. Click on a word in the "Looking For A Muscle?" Column and it will show up on the picture. See it here.

Carpal tunnel syndrome is a fairly common affliction. The carpal tunnel is where tendons and the median nerve--which goes to the thumb, index, middle and ring fingers--all pass through a narrow spot in the wrist. If any one of a number of things puts pressure on the nerve, it can cause pain, numbness, loss. This site has several videos of surgery performed endoscopically.

Here is a site where you can see where every muscle in the human body goes. There is a cute animated GIF of a skeleton, too. Click here.

Back to the robot hand introduction page.

Back to the science toymaker home page.

I'd like to know how this project goes for you. I'm happy to answer questions about it. Feedback from you is an important way for me to know what works and what needs clarification.
contact me