Suddenly, the remaining fingertip was loaded with most of Hal's weight. A doctor found that the tendon was only partially ripped. For two weeks, Hal's finger ached. It was six weeks before he could brush his teeth without noticing the weakness in the last joint of his finger. It was over a year before his finger had recovered its pre-accident strength.
Tendons heal slowly.
My mind wandered while my fingers searched for a hold. I thought about my fingers. It can amplify a few pounds of force moving over a large distance into a large force moving over a small distance Fingers, however, operate at a mechanical disadvantage The tendon connecting the bone of the fingertip to the muscle in the arm must pull with a strong force to resist a small force applied to a fingertip. The one hundred pounds exerted on Hal's fingertip was amplified to several hundred pounds of tension in Hal's finger tendon and muscle That was enough force to rip the tendon.