Keel (bird anatomy) Keel (bird anatomy) 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
Pan American Association of Anatomy Pan American Association of Anatomy The Pan American Association of Anatomy (PAA) is a public, nonprofit, scientific organization that brings together professionals engaged in the study of Anatomy and related sciences in the American continent. The Pan American Association of Anatomy (PAA) was created in July 1966 in Mexico City at the 1st Pan American Congress of Anatomy, which was held together with the 3rd National Congress of the Mexican Society of Anatomy. Its mentor was the Prof. Dr. Liberato J. A. Didio. The need for a Pan American Association of Anatomy was proposed by Prof. Di Dio during the