Anatomically correct muscle rig following the skeleton movement

Hi everyone!

I try to get an anatomically correct arm. Focus is on the muscle system. Ater first successful tests with easy mucles I tried a muscle more complex: The biceps. The tendrils start at 2 locations (back and shoulder) go to the arm where the actual muscle is and finally the tendrils end at the lower part of the arm.
I set up a basic armature for the arm consisting of 2 bones (upper and lower).
Then to test the lower tendril I also set up 2 bones: one for the muscle, one for the tendril. For the tendril bone I used a copy rotation constraint. Also tried armature constraint. Both fail because after the skeleton arm is turned far enough, the muscle crosses the boundaries of the skelton (which is not anatomically correct :smiley: )

Here is a picture:

Here is a link to the blend file

Basically I try to create something similar to this:

Can anyone give me a hint how to connect the armatures correctly?

Thanks!

Shouldn’t you first make the muscle (bicep or tricep?) follow the upper arm bone? This should take care of most of the problem, no?