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Pectus excavatum is a structural deformity of the anterior thoracic wall in which the sternum and rib cage are shaped abnormally. This produces a caved-in or sunken appearance of the chest. It can either be present at birth or develop after puberty. Pectus excavatum can impair cardiac and respiratory function and cause pain in the chest and back.
A plant derived from the asexual vegetative reproduction of a parent plant, with both plants having identical genetic compositions. coalescent Having plant parts fused or grown together to form a single unit. cochleariform Concave and spoon-shaped. cochleate Coiled like a snail's shell. coenobium An arranged colony of algae that acts like a ...
A function f is concave over a convex set if and only if the function −f is a convex function over the set. The sum of two concave functions is itself concave and so is the pointwise minimum of two concave functions, i.e. the set of concave functions on a given domain form a semifield.
The sternum (pl.: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage , thus helping to protect the heart , lungs , and major blood vessels from injury.
Plant anatomy or phytotomy is the general term for the study of the internal structure of plants.Originally, it included plant morphology, the description of the physical form and external structure of plants, but since the mid-20th century, plant anatomy has been considered a separate field referring only to internal plant structure.
The plant morphologist goes further, and discovers that the spines of cactus also share the same basic structure and development as leaves in other plants, and therefore cactus spines are homologous to leaves as well. This aspect of plant morphology overlaps with the study of plant evolution and paleobotany.
Leaves of most plants include a flat structure called the blade or lamina supported by a network of veins, a petiole and a leaf base; [1] but not all leaves are flat, some are cylindrical. [ citation needed ] Leaves may be simple, with a single leaf blade, or compound, with several leaflets .
The sterile leaves are modified leaves whose function is to protect the fertile parts or to attract pollinators. [1] The branch of the flower that joins the floral parts to the stem is a shaft called the pedicel , which normally dilates at the top to form the receptacle in which the various floral parts are inserted.