Shoulder Ligamament

["Richard W. Travsky" <rtravsky@uwyo.edu>]

http://www.sciencedaily.com/releases/2006/12/061218081421.htm

Brown and Harvard scientists have learned that a single ligament at the 
shoulder joint stabilizes the wings of birds during flight. In an advanced 
online publication of Nature, they explain how this tough bit of tissue 
evolved to become a linchpin for todays fliers.

How animals got off the ground  how limbs became wings  is a fascinating 
question, said team leader David Baier, a post-doctoral research fellow in 
the Department of Ecology and Evolutionary Biology at Brown. What we 
learned here is that, in the evolutionary line to birds, a single ligament 
played an increasingly important role in flight.
...