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
Gray's Anatomy medicine; the anatomy of facial aging; and technical aspects and applications of diagnostic radiology. The senior editor of this book and accompanying website on ExpertConsult is Professor Susan Standring, who is Emeritus Professor of Anatomy at King's College London. The three most recent editions differ from all previous editions in an important aspect: they present anatomical structures by their regional anatomy (i.e. ordered according to what part of the body the structures are located in – e.g. the anatomy of the bones, blood vessels and nerves, etc. of the upper extremity is described in one place). All editions of "Gray's