An Analytical Expression for the D.I.P. - P.I.P. Flexion Interdependence of the Human Finger

Empirical evidence shows that a strong correlation exists between the flexion angles of the distal interphalangeal joint (D.I.P.), and the proximal interphalangeal joint (P.I.P.) of the human finger. The aim of the study therefore is to find an analytical expression for this correlation, from where the first derivative may be calculated. Especially the visualisation of the rate of change of the D.I.P. flexion versus P.I.P. flexion provides an additional and clear-cut discriminatory tool between normal and pathological states of the finger.