Dictionary

rickets, vitamin D–resistant See rickets, hypophosphatemic.

rickets, renal Rickets-like bone malformations that are caused by prolonged inflammation of the kidneys.

rickets, hypophosphatemic A rare genetic form of rickets that is characterized by low blood phosphate level (hypophosphatemia), defective intestinal absorption of phosphate, and unresponsiveness to vitamin D. The basic problem in hypophosphatemic rickets is decreased resorption of phosphate by the tubules in the kidney. Females typically have less severe disease than males. The condition is…

rickets, celiac Rickets caused by failure of the intestines to absorb calcium and fat from foods. See also celiac sprue.

rickets A disease of infants and children that disturbs normal bone formation (ossification), leading to failure to mineralize bone. Rickets softens bone, producing osteomalacia, and permits marked bending and distortion of bones. Other features of rickets include softness of the infant’s skull (craniotabes), enlargement of the front end of the ribs (creating the “rachitic rosary”),…

ribozyme An RNA molecule that has enzymatic activity. See also ribonucleic acid.

ribosome A tiny structure in the cytoplasm of a cell (outside the nucleus) that functions as the protein factory for the cell.

ribonucleic acid A nucleic acid that is similar to DNA but contains ribose rather than deoxyribose. Abbreviated RNA. RNA, in fact, can form upon a DNA template. The several classes of RNA molecules play important roles in protein synthesis and other cell activities. See also messenger RNA; RNA, ribosomal; RNA, transfer.

rib, sternal See true rib.

rib, floating or vertebral or fluctuating – See false rib.

rib, cervical An extra rib that arises from the seventh cervical vertebra. It is located above the normal first rib. A cervical rib is present in only about 1 in 200 people. It may cause pinching of nearby nerves or arteries, in which case it sometimes is removed surgically.

rib One of the 12 paired arches of bone that form the skeletal structure of the chest wall (the rib cage). The ribs attach to the vertebrae of the spine in the back. The 12 pairs of ribs consist of 7 pairs of ribs that attach to the sternum in the front and are known…