A new test for demonstrating the action of flexor digitorum superficialis (FDS) tendon

The available tests for demonstrating the action of flexor digitorum superficialis (FDS) can be used on one finger at a time. A new test is proposed which can test all the four FDS tendons simultaneously. It was administered along with other available tests on 100 uninjured hands of 50 volunteers and on seven clinical cases with FDS injury. It correlated fully (100%) with the standard test on middle and ring fingers and with the pulp-to-pulp forced pinch test with the thumb on index fingers. It was more accurate than the standard test in detecting the presence of FDS action on the little finger. It was found to be in strong agreement with the modified standard test on little finger with a kappa coefficient of 0.98. It correlated fully for the absence of FDS tendon action in seven operatively proved cases. The present test is a new test which is faster and more versatile than the available tests.