Trace the "flow lines" of the muscles. If your sculpt's lines are straight but the reference's lines are curved, you’ve missed the tension of the pose. Conclusion: Motion is the Key to Realism
Most sculptors fail at the wrist because they sculpt a hinge. The AFS PDF reveals the complex rotational geometry. arm and hand in motion by anatomy for sculptors pdf better
The arm and hand work together to facilitate a wide range of movements, including: Trace the "flow lines" of the muscles
If you are sculpting right now, use this derived from the book's methodology: arm and hand in motion by anatomy for sculptors pdf better