MEASUREMENT OF THE ARC OF D IG ITAL FLEX ION AND JOINT MOVEMENT RANGES

Dynamic digital flexion was examined by video recording healthy subjects making a fist. The arc of the fingertip sweep from full extension to full flexion was replayed frame by frame and plotted. A similar technique was employed to measure the MP, PIP and DIP joint angles throughout digital flexion. Graphs were plotted of MP against PIP, and PIP against DIP flexion. These results were related to a theoretical 45 ° line. The fingertip appears to sweep through an elliptical pathway when flexing, rather than an equiangular curve. Graphs of joint flexion showed that male and female fingers flex in a similar fashion, as do the index and little finger. Graphs of PIP against DIP flexion suggest some limiting mechanism of either the extensor or flexor system. These graphs give useful insights into the complex mechanisms of dynamic digital f exion, and may be of diagnostic and prognostic importance. Journal of Hand Surgery (British and European Volume, 1995) 20B. " 6. " 836-840 Although the ability to grip has played an important role in the development of man, the mechanism of digital flexion remains incompletely understood