[identity profile] iarraidh.livejournal.com 2007-09-24 09:00 pm (UTC)(link)
One of the faults I see in 99% of the animation today is the inaccurate articulation of the shoulder area.
they treat it as if it's a fixed hard points equidistant from the spine. The shoulder is a multiple point combination of a-frame, rotator, flexor, etc.
The most "fixed" points are where the collar bone connects to the sternum and where the shoulder blade floats across the back plane. rarely do I see anyone capture this complicated movement correctly.