calcium excess An elevated blood calcium level (hypercalcemia), which can cause muscle weakness and constipation, affect the conduction of electrical impulses in the heart (heart block), lead to calcium stones in the urinary tract, impair kidney function through nephrocalcinosis, and interfere with the absorption of iron, predisposing the person to iron deficiency.
calcium deficiency A low blood level of calcium (hypocalcemia), which can make the nervous system highly irritable, causing spasms of the hands and feet (tetany), muscle cramps, abdominal cramps, overly active reflexes, and so on. Chronic calcium deficiency contributes to poor mineralization of bones, soft bones (osteomalacia) and osteoporosis, and, in children, rickets and impaired…
calcium A mineral found mainly in the hard part of bones, where it is stored. Calcium is added to bone by cells called osteoblasts and removed from bone by cells called osteoclasts. Calcium is essential for healthy bones and is also important for muscle contraction, heart action, and normal blood clotting. Food sources of calcium…
calcitonin A hormone produced by the thyroid gland that lowers the levels of calcium and phosphate in the blood and promotes the formation of bone. Bone is in a constant state of remodeling. Old bone is removed by cells called osteoclasts, and new bone is added by cells called osteoblasts. Calcitonin inhibits bone removal by…
calcinosis An abnormal deposit of calcium salts in body tissues. Examples include the calcifications in the skin from scleroderma and in the muscle from polymyositis.
calcified granuloma A node-like type of tissue inflammation that has a specific appearance under a microscope (granuloma) and contains calcium deposits. Because it usually takes some time for calcium to be deposited in a granuloma, it is generally assumed that a calcified granuloma is an old granuloma, or an old area of inflammation. For example,…
calcification The process of suffusing tissues with calcium salts.
calcific bursitis Chronic inflammation of a bursa (bursitis) that leads to calcium deposits in the bursa. The calcification can occur as long as the inflammation is present. See also bursa; bursitis.
calcaneus The heel bone, a more or less rectangular bone at the back of the foot. Also known as os calcis.
calcaneocuboid joint The joint located in the foot between the calcaneus bone and the cuboid bone. It is a gliding type of joint. The ligaments that serve to support and strengthen this joint are called the capsular, dorsal calcaneocuboid, bifurcated, long plantar, and plantar calcaneocuboid ligaments.
calcaneal spur A bony spur, also known as a heel spur, that projects from the back or underside of the heel bone (the calcaneus) and that may make walking painful. Calcaneal spurs are associated with inflammation of the Achilles tendon (Achilles tendinitis), and cause tenderness and pain at the back of the heel, which is…
calamine An astringent made from zinc carbonate or zinc oxide, customarily used in lotion form to treat skin problems or insect bites that cause itching or discomfort.