EFFICIENCY OF THE FLEXOR TENDON PULLEY SYSTEM IN HUMAN CADAVER HANDS

The efficiency of the flexor tendon system was examined in a human cad aver model. Pulleys were randomly sectioned, and the results were eval uated on the basis of the tendon excursion, force generated at the fin gertip, and the work (force multiplied by distance) involved, as compa red to the intact pulley system. When a single minor pulley (A1 or A5) was cut, there was no statistical difference in work efficiency or ex cursion efficiency from controls, Cutting all minor pulleys (A1, A3, A 5) lead to a significant loss in excursion efficiency. The intact thre e pulley systems of A2, A3, and A4 were near normal and statistically better than A2 and A4 together for work efficiency. Cutting one of the major pulleys (A2, A4) resulted in significant changes in efficiency, but what was unexpected was to find an 85% loss of both work and excu rsion efficiency for the loss of A4 but only an excursion difference o f 94% for the loss of A2. Our findings demonstrated that in this model , with the influence of the skin removed, A4 absence produced the larg est biomechanically measured efficiency changes and that a combination of A2, A3, and A4 was necessary to preserve both work and excursion e fficiency.