The invention relates to an artificial joint element (1) for use in one or
more single joints in a system of joints that consists of a combination
of several kinematically coupled single joints, (series connection), in
particular for use in one or more human finger joints. Said element
comprises an essentially concave joint shell (2) and an essentially
convex joint head (3). The aim of the invention is to obtain displacement
characteristics for the artificial joint element (1), resulting from the
additional degrees of freedom that are produced by incongruence, that
mimic the natural behavior in an optimal manner. To achieve this, the
joint element (1, 6) comprises at least four degrees of freedom and when
used in the metacarpophalangeal joint, five degrees of freedom. For this
purpose, the concave joint shell (2) comprises a curved contact line
running over its surface with a first radius (R) and the concave joint
head (3) has a contact line that is also curved running over its surface
with a different second radius (r), which is smaller than the radius (R)
of the contact line of the joint shell (2).