Keel (bird anatomy)

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
This stylised bird skeleton highlights the keel bone

A keel or carina (plural carinae) in bird anatomy is an extension of the sternum (breastbone) which runs axially along the midline of the sternum and extends outward, perpendicular to the plane of the ribs. The keel provides an anchor to which a bird's wing muscles attach, thereby providing adequate leverage for flight. Keels do not exist on all birds; in particular, some flightless birds lack a keel structure.

Historically, the presence or absence of a pronounced keel structure was used as a broad classification of birds into two orders: Carinatae (from carina, "keel"), having a pronounced keel; and ratites (from ratis, "raft" — referring to the flatness of the sternum), having a subtle keel structure or lacking one entirely. However, this classification has fallen into disuse as evolutionary studies have shown that many flightless birds have evolved from flighted birds. The current definition of Carinatae now includes all extant birds.

See also

References

  • Cummins, Jim (April 1, 1996). "Anatomy of Flight". Retrieved January 31, 2005.
  • Ramel, G. "The Anatomy of Birds". Earth-Life Web Productions. Retrieved January 31, 2005.


Retrieved from "https://en.wikipedia.org/w/index.php?title=Keel_(bird_anatomy)&oldid=842213510"
This content was retrieved from Wikipedia : http://en.wikipedia.org/wiki/Keel_(bird_anatomy)
This page is based on the copyrighted Wikipedia article "Keel (bird anatomy)"; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA