Category: C

  • Cinchona

    The dried bark of Cinchona trees, formerly used in medicine to stimulate the appetite and to prevent hemorrhage and diarrhea. Taken over prolonged periods, it may cause cinchonism. Cinchona is the source of quinine. Poisoning caused by an overdose of cinchona or the alkaloids quinine, quinidine, or cinchonine derived from it. The symptoms are commonly…

  • Cinchocaine

    A local anesthetic used in dental and other operations and to relieve pain. It is applied directly to the skin or mucous membranes or injected at the site where anesthesia is required or into the spine. Side-effects such as yawning, restlessness, excitement, nausea, vomiting, and allergic reactions sometimes occur.  

  • Chrysops

    A genus of bloodsucking flies, commonly called deer flies. Female flies, found in shady wooded areas, bite man during the day. Certain species in Africa may transmit the tropical disease loiasis to man. In the US C. discalis is a vector of tularemia.  

  • Chronaxie

    A measurement of the electrical excitability of a nerve or muscle, formerly used in the detection of damage to the motor nerves. Its use has largely been superseded by ‘electromyography, the direct recording of electrical activity in the muscles. A number expressing the sensitivity of a nerve to electrical stimulation. It is the minimum duration,…

  • Chromatopsia

    A rare symptom of various conditions. Sometimes everything looks reddish to patients after removal of their cataracts; patients suffering from digitalis poisoning may see things in green or yellow. Similar disturbances of color may be experienced by people recovering from inflammation of the optic nerve.  

  • Chromatolysis

    The dispersal or disintegration of the microscopic structures (NissI bodies) within the nerve cells that normally produce proteins. It is part of the cell’s response to injury. The dissolution of chromophil substance (Nissl bodies) in neurons in certain pathological conditions, or following injury to the cell body or axon.    

  • Christmas disease

    A disorder that is identical in its effects to ‘hemophilia, but is due to a deficiency of a different blood coagulation factor, the Christmas factor (Factor IX). A hereditary disorder of blood coagulation which can only be distinguished from haemophilia by laboratory tests. It is so-called after the surname of the first case reported in…

  • Chorioepithelioma

    A rare form of cancer originating in the outermost of the membranes (chorion) surrounding the fetus and affecting the womb or the site of a pregnancy outside the womb, e.g. a fallopian tube (see ectopic pregnancy). Chorioepithelioma, which rapidly invades and causes secondary deposits, is highly malignant; it may occur after *hydatidiform mole, pregnancy, or…

  • Chordoma

    A tumor arising from remnants of the embryonic ‘notochord. The classical sites are the base of skull and the region of the sacrum. A rare type of tumor that occurs at any place along the vertebral column. It is composed of embryonic nerve tissue and vacuolated physaliform cells. The neoplasm may cause death because of…

  • Chorda

    A cord, tendon, or nerve fiber. The chordae tendineae are string-like processes in the heart that attach the margins of the mitral and tricuspid valve leaflets to projections of the wall of the ventricle (papillary muscles). Rupture of the chordae, through injury, endocarditis, or degenerative changes, results in mitral incompetence. The notochord is the embryonic…