The interaction between the handle and operator's hand affects the comfort and 
safety of tool and machine operations. In most of the previous studies, the 
investigators considered only the normal contact forces. The effect of friction 
on the joint moments in fingers has not been analyzed. Furthermore, the observed 
contact forces have not been linked to the internal musculoskeletal loading in 
the previous experimental studies. In the current study, we proposed a universal 
model of a hand to evaluate the joint moments in the fingers during grasping 
tasks. The hand model was developed on the platform of the commercial software 
package AnyBody. Only four fingers (index, long, ring, and little finger) were 
included in the model. The anatomical structure of each finger is comprised of 
four phalanges (distal, middle, proximal, and metacarpal phalange). The 
simulations were performed using an inverse dynamics technique. The joint angles 
and the normal contact forces on each finger section reported by previous 
researchers were used as inputs, while the joint moments of each finger were 
predicted. The predicted trends of the dependence of the distal interphalangeal 
(DIP) and proximal interphalangeal (PIP) joint moments on the cylinder diameter 
agree with those of the contact forces on the fingers observed in the previous 
experimental study. Our results show that the DIP and PIP joint moments reach 
their maximums at a cylinder diameter of about 31mm, which is consistent with 
the trend of the finger contact forces measured in the experiments. The proposed 
approach will be useful for simulating musculoskeletal loading in the hand for 
occupational activities, thereby optimizing tool-handle design.