Of course, bicep area is not the only place to use the muscle bone.  You can use it all over your characters body.  I found it pretty useful for chest muscles, Forearm muscles, butt, neck and leg muscles.

And again, by no means this is the only way to simulate muscle bulging for your characters and is not the only muscle solution.  This method does not simulate muscle jiggle and does not has any dynamics that plug-ins like Hercules or ACT do.  And you don't necessarily have to use muscles to simulate bulging.  You can also use joint angle deformer which is built in skin modifier.  There's a Bulge editor in Physique that comes with Character Studio.   You can also drive your bulging with a morpher modifier and using reactor controller on a morpher channel to react to Bipeds joint angle (works nicely with Character Studios Biped, for IK driven joints, you'll need to use a script to extract the joint angle).  Max 7 soon to be released promises a Skin Morph Modifier which will morph your mesh depending on a joints angle.  So there are lots of solutions to muscle bulging, and using muscle bones is just one of many.

I hope this article helps.  If you have any questions or comments, don't hesitate to drop me an e-mail at [email protected]