Finger stability in precision grips

Abstract

Significance Hand skills rely on the precision grip to hold objects with the fingertips. In rare instances, our finger’s joints undergo a form of buckling when we push with the fingertip and snap into hyperextension. Suppressing this instability is crucial for hand use, but how the nervous system avoids buckling is unknown. We studied people applying forces with the tip of their index fingers and found that the nervous system relies on the spring-like action of muscles for stability. The muscles cocontract to stabilize the joints but reduce the strength and compliance of our fingers. Thus, the motor skill of precision grip arises from the careful control of muscle cocontraction to balance the trade-off between finger stability, strength, and flexibility.