Dynamic cosmesis

Cosmesis is the term used in prosthetics to describe how a particular device looks. A device is considered to be cosmetic in appearance if it is aesthetically pleasing and looks like the limb it is designed to replace in both its lines and color. However, a device may be statically correct in appearance but it can look wrong or lifeless when it is in motion. In this instance, the device has good static cosmesis but poor dynamic cosmesis. 

People see what they expect to see, so if a person with an artificial limb replacement looks and moves in an expected manner the fact of the artificial limb will often go unnoticed by casual observers. Often a hand replacement can have only a vague resemblance to the natural hand but because it is moved in a natural-looking manner, it can pass undetected unless closely scrutinized. Here the device has poor static cosmesis but good dynamic cosmesis. 

Dynamic cosmesis is firequently the more important of the two forms of cosmesis, but it is frequently overlooked because it is difficult to achieve. Dynamic cosmesis can be enhanced by preserving as much of the person s residual motion as possible. For example, a partial hand prosthesis should not interfere with residual wrist motion because the wrist is used extensively in the positioning of the hand in space. Finally, a device can be considered to be functionally cosmetic if at a glance it is not immediately recognizable as an artificial hand regardless of whether it is in motion or not or whether it is or is not handlike when stationary. 

---