HUMERAL ROTATION

[darren.naish@port.ac.uk]

This just in..

POORE, S.O., ASHCROFT, A., SANCHEZ-HAIMAN, A.
 and GOSLOW, G.E. 1997. The contractile properties of the m. 
supracoracoideus in the pigeon and starling: a case for long-axis 
rotation of the humerus. _The Journal of Experimental Biology_ 200: 
2987-3002.

As the title says, this paper is mostly about role of the SC in two 
extant birds. It's worthy of attention here, however, in that the 
observations are extended to Mesozoic birds who, in lacking 
morphologically derived SC muscles typical of modern flying birds, 
would not have had such well developed high-velocity recovery strokes 
and therefore would have had more limited flight abilities.

Evolution of the SC has allowed the development of a large rotational 
component to humeral movement in birds - Poore at al. argue that this 
'..was an important step in the evolution of the wing upstroke and in 
the ability to supinate (circumflex) the manus in early upstroke, a 
movement fundamental to recucing air resistance during the recovery 
stroke'.

Humeral rotation has been described for pterosaurs: a paper by 
Hazlehurst and Rayner puts the argument best I recall.

"I'm hungrier than a brachiosaur on a low-fern diet"

Why am I mentioned in the current SVP newsletter? Can someone tell me 
please - I haven't seen it.

DARREN NAISH
darren.naish@port.ac.uk