Seeing what’s missing

Have you ever watched an animation of a horse in motion? 

At the beginning of this video, you see an equine skeleton’s limbs moving sequentially. Sections of the spine — between the head and neck at the top and in the tail at the other end — ripple in a wavelike fashion. As you watch, muscle and soft tissue layers appear, followed by the skin, and eventually, the tail and mane materialize. 

In his comments, New Zealand digital artist Julian Butler tells us he used photos along with data acquired from motion capture, CT scans, and X-rays to create this simulation. The resulting model serves an admirable purpose: movies can utilize it when it would be too risky to use a live horse or when the script calls for something that a real animal cannot do. 

As useful as the model might be, I couldn’t help but notice that something was missing regarding horse movement. Specifically, the chest didn’t change shape, and the rest of the spine wasn’t undulating as the horse moved. 

While visualization may fit with the commonly held idea that a ribcage is solid and unmoving, maintaining this stiffness would require an incredible and incessant amount of muscular effort, inhibiting the horse’s natural, necessary trunk motion. The resulting rigidity would interfere with the horse’s ability to breathe, destroy the fluidity of its gait, eliminate shock absorption and force transmission, and make locomotion clunky and dangerously inefficient.  

The Feldenkraisian insight that the chest is more of a rib basket than a cage is central to understanding well-organized whole-body movement. Though the distributed movements of the chest – breast bone, ribs, and the vertebrae they attach to – may be small, they are essential to economic, coordinated action, whether considering horses or humans in motion.