A keel (or in Latin ''carina''), in anatomy, is a structure whose shape resembles the

keel The keel is the bottom-most longitudinal structural element on a vessel. On some sailboats, it may have a hydrodynamic and counterbalancing purpose, as well. As the laying down of the keel is the initial step in the construction of a ship, in Br ...

of a boat. The term may refer to:

Animal 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

perpendicular In elementary geometry, two geometric objects are perpendicular if they intersect at a right angle (90 degrees or π/2 radians). The condition of perpendicularity may be represented graphically using the ''perpendicular symbol'', ⟂. It can ...

extension of a bird's breastbone, to which wing muscles anchor *

Keel (slug) Slug, or land slug, is a common name for any apparently shell-less terrestrial molluscs, terrestrial gastropod mollusc. The word ''slug'' is also often used as part of the common name of any gastropod mollusc that has no shell, a very reduced ...

, a morphological feature on the back of some land slugs which resembles the keel of an upturned boat * Keel in a

gastropod shell The gastropod shell is part of the body of a Gastropoda, gastropod or snail, a kind of mollusc. The shell is an exoskeleton, which protects from predators, mechanical damage, and dehydration, but also serves for muscle attachment and calcium s ...

, a sharp ridge or edge at the shoulder or the center of periphery of the whorls of a snail shell * The caudal keel in

fish anatomy Fish anatomy is the study of the form or morphology of fish. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish. In practice, fish anatomy and fish physiology co ...

, a strengthening ridge at the base of the tail *

Keeled scales Keeled scales refer to reptile scales that, rather than being smooth, have a ridge down the center that may or may not extend to the tip of the scale, Campbell, J. A., Lamar, W. W. (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithac ...

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

scales that have a ridge down the center, rather than being smooth

Human anatomy

Carina of trachea In anatomy, the carina or tracheal bifurcation is a ridge of cartilage in the trachea that occurs between the division of the two main bronchi. Structure The carina occurs at the lower end of the trachea (usually at the level of the 4th to 5th ...

Sagittal keel In the human skull, a sagittal keel, or sagittal torus, is a thickening of part or all of the midline of the frontal bone, or parietal bones where they meet along the sagittal suture, or on both bones. Sagittal keels differ from sagittal crests, w ...

, a feature of the skull

Plant anatomy

* Keel (petal), the two bottom

petal Petals are modified Leaf, leaves that surround the reproductive parts of flowers. They are often advertising coloration, brightly colored or unusually shaped to attract pollinators. All of the petals of a flower are collectively known as the ''c ...

s, below the wings, in

flowers A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

of the subfamily

Faboideae The Faboideae are a subfamily of the flowering plant family Fabaceae or Leguminosae. An acceptable alternative name for the subfamily is Papilionoideae, or Papilionaceae when this group of plants is treated as a family. This subfamily is wide ...

of the flowering plant family Fabaceae; sometimes joined to form a structure whose shape resembles the

of a boat

Animal anatomy

Human anatomy

Plant anatomy

See also