- Keel (bird)
A keel in
bird anatomy is an extension of thesternum 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 adequateleverage forflight . Keels do not exist on all birds; in particular, someflightless bird s lack a keel structure.Historically, the presence or absence of a pronounced keel structure was used as a broad classification of birds into two classes:
Carinatae (from "carina", "keel"), having a pronounced keel; andRatite s (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.ee also
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Bird skeleton
*Ornithology References
* Cummins, Jim (April 1, 1996). [http://numbat.murdoch.edu.au/Anatomy/avian/avian2.html "Anatomy of Flight"] . Retrieved January 31, 2005.
* Ramel, G. [http://www.earthlife.net/birds/anatomy.html "The Anatomy of Birds"] . Earth-Life Web Productions. Retrieved January 31, 2005.
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