X-ray Videos Show Animal Skeletons in Motion

Scientists are filming animals as they run on treadmills (or fly in wind tunnels) and then using a new 3-D video technique to peek beneath the skin with X-Rays to see the skeletons on the move. The final process of making the movies is still in the design phase, but some scaled down and simplified versions are already available (see a movie of a pig walking).

The scientists are using this approach to understand how the biomechanics of flight evolved. To trace flight back in time, they made skeletal movies of alligators—the closest living relatives of birds—as they walked along a moving treadmill.

Another recent study discovered a flight-helping ligament that transformed as winged birds evolved. Now, the scientists are preparing to study birds as they toddle up steep inclines while flapping their wings. By comparing the skeletal movies from the walking birds with those in flight, the scientists expect learn other key features needed for flight.



The technique will also breathe life into fossil bones from extinct animals like theropod dinosaurs. Three-dimensional images of the brittle bones can be fitted with moving skeletons from modern-day relatives.

Other future uses of the technology could include:

* Measuring the forces applied to each joint as a person runs or a frog jumps.
* Testing new theories of biomechanics, such as muscle-tendon interactions.
* Studying the evolution of joints, from the cartilaginous joints in most mammals to the “more advanced” joints in humans, which are bonier.
* Planning orthopedic surgeries and comparing the effectiveness of different approaches.
* Creating better treatments for shoulder, wrist, knee and back injuries.

In a related article, see this video of a shrimp on a treadmill.