| optic radiation | The massive, fanlike fibre system passing from the lateral geniculate body of the thalamus to the visual cortex (striate or calcarine cortex, area 17 of Brodmann); the fibres follow the retrolenticular and sublenticular limbs of the internal capsule into the corona radiata but they curve back along the lateral wall of the temporal and occipital horns of the lateral ventricle to the striate cortex on the medial surface and pole of the occipital lobe. Synonym: radiatio optica, geniculocalcarine radiation, geniculocalcarine tract, Gratiolet's fibres, Gratiolet's radiation, occipitothalamic radiation, Wernicke's radiation. (05 Mar 2000) |
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| electromagnetic radiation | <physics> Radiation (such as radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays) which consists of associated, interacting electric and magnetic field waves which travel at the speed of light. All forms of electromagnetic radiation can be transmitted through vacuum. Electromagnetic waves in plasmas are generally more complex in their behaviour, depending on their frequency. (09 Oct 1997) |
| excitation radiation | <radiobiology> Line radiation (at characteristic frequencies / wavelengths) as a result of the promotion of electrons or other constituent particles of a larger system to excited states, and the subsequent de-excitation of these states by radiative transitions. (09 Oct 1997) |
| external radiation | Radiation therapy that uses a machine located outside the body to aim high-energy rays at the cancer. (16 Dec 1997) |
| external radiation therapy | Radiation therapy using a machine located outside the body to aim high-energy rays at a tumour. (12 Dec 1998) |
| ultraviolet radiation | <physics> Invisible light, next to visible light in the electromagnetic spectrum. The most common source of ultraviolet radiation is the sun. Acronym: UV (16 Dec 1997) |
| K-radiation | Usually a very penetrating form of x-radiation excited by cathode rays (high speed electrons) impinging upon a metal anode such as tungsten; the energy of the radiation is a function of the binding energy of the K-shell electrons of the metal anode. (05 Mar 2000) |
| L-radiation | An x-radiation of slight penetrating power excited by cathode rays (high speed electrons) impinging on a metal anode; the energy of the radiation is a function of the binding energy of the L-shell electrons of the metal anode. (05 Mar 2000) |
| abdominal pregnancy | The implantation and development of the ovum in the peritoneal cavity, usually secondary to an early rupture of a tubal pregnancy; very rarely, primary implantation may occur in the peritoneal cavity. Synonym: abdominocyesis, intraperitoneal pregnancy. (05 Mar 2000) |
| aborted ectopic pregnancy | The rupture of an oviduct, the seat of ectopic pregnancy, or extrusion of the product of conception through the fimbriated end of the oviduct; aborted ectopic pregnancy, the pregnancy having originated in the fallopian tubes. Synonym: aborted ectopic pregnancy. (05 Mar 2000) |
| alcohol, pregnancy | The consumption of alcohol during pregnancy carries the danger of damaging the foetus. (12 Dec 1998) |
| ampullar pregnancy | Tubal pregnancy situated near the midportion of the oviduct. (05 Mar 2000) |
| bigeminal pregnancy | A pregnancy that may result from the fertilization of two separate ova or of a single ovum. See: twin. Synonym: bigeminal pregnancy. (05 Mar 2000) |
| macrocytic anaemia of pregnancy | An anaemia occurring in pregnancy, related to folate deficiency and characterised by a low level of haemoglobin and a reduced number of erythrocytes, which are larger than normal (macrocytes). (05 Mar 2000) |
| papular dermatitis of pregnancy | Intensely pruritic papular eruption of torso and extremities occurring throughout pregnancy, with no systemic toxicity; may be similar to pruritic urticarial papules and plaques of pregnancy. (05 Mar 2000) |