| IO | incisal opening; inferior oblique; inferior olive; internal os; interorbital; intestinal obstruction... |
|---|---|
| PICA | percutaneous transluminal coronary angioplasty; Porch Index of Communicative Abilities; posterior in... |
| DOLV | Double Outlet Left Ventricle |
| DORV | Double Outlet Right Ventricle |
| DOLV | double outlet left ventricle |
| disputed neurogenic thoracic outlet syndrome | <syndrome> A highly controversial disorder in which the brachial plexus is reputedly repressed at one or more sites along its course, particularly within the interscalene triangle, and between the normal first thoracic rib and some other structures; frequently attributed to trauma (particularly automobile accidents, and most often diagnosed in young to middle-aged women; no characteristic clinical presentation, although forequarter pain is characteristic; no definite objective findings are present, and no undisputed ancillary diagnostic studies are available. (05 Mar 2000) |
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| double outlet right ventricle | <cardiology, embryology> Incomplete transposition of the great vessels in which both the aorta and the pulmonary artery arise from the right ventricle, often associated with a subaortic ventricular septal defect. (12 Dec 1998) |
| outlet | An exit or opening of a passageway. (05 Mar 2000) |
| outlet forceps delivery | Delivery by forceps applied to the foetal head when it has reached the perineal floor and is visible between contractions. (05 Mar 2000) |
| thoracic outlet syndrome | <syndrome> Condition due to compromise of blood vessels or nerve fibres between the armpit (axilla) and base of the neck. (12 Dec 1998) |
| true neurogenic thoracic outlet syndrome | <syndrome> Very chronic axon loss brachial plexopathy, caused by compromise of the lower trunk fibres by a congenital band extending from a rudimentary cervical rib to the first thoracic rib; rare disorder, found mostly in young to middle-aged women, that presents with unilateral hand wasting and weakness, particularly involving the lateral thenar eminence; sometimes accompanied by intermittent discomfort along the medial forearm and hand. Synonym: cervical rib and band syndrome, classic cervical rib syndrome. (05 Mar 2000) |
| angle of aperture | <ophthalmology, optics> The angle formed by lines drawn from the ends of the diameter of a lens to its point of focus. See: angular aperture. (05 Mar 2000) |
| angular aperture | The angle, in air, of light that passes from the object to the ends of the diameter of the front lens of the microscope objective. (05 Mar 2000) |
| anterior nasal aperture | The anterior nasal opening in the skull. Synonym: apertura piriformis, piriform opening. (05 Mar 2000) |
| aperture | <physics> The opening in an optical system which restricts the size of the bundle of rays incident on a given surface. (Usually circular and specified by diameter.) (09 Oct 1997) |
| aperture, angular | <microscopy> The angle between the most divergent rays that can pass through a lens to form the image of an object. The angle subtended between the axis of a lens and the largest accepted angle of the image-forming rays. With microscope objectives the trigonometric sine of this angle is used to define numerical aperture but as measured from the axial object point. (05 Aug 1998) |
| aperture correction | <microscopy> An electronic process used in some high-resolution video cameras and monitors that compensates for the loss in sharpness of detail due to the finite dimensions (aperture) of the scanning beam. (05 Aug 1998) |
| aperture diaphragm | A metal device that limits the area of the beam emerging from an X-ray tube. (05 Mar 2000) |
| aperture, effective | <microscopy> The diameter of the entrance pupil: it is the apparent diameter of the limiting aperture measured from the front. (05 Aug 1998) |
| aperture for electron microscopy | <technique> Anode aperture: The opening in the accelerating voltage anode shield of the electron gun through which the electrons must pass to irradiate the specimen. Condenser aperture: An opening in the condenser lens controlling the number of electrons entering the lens and the angular aperture of the electron beam. The angular aperture can also be controlled by the condenser lens current. Physical objective aperture: A metallic diaphragm, with a small central hole, used to limit the cone of electrons accepted by the objective lens. This improves image-contrast since highly scattered electrons are prevented from arriving at the Gaussian image plane and therefore cannot contribute to background fog. Aplanatic. Free from spherical aberration and coma. (05 Aug 1998) |