Medical Dictionary Definitions A-Z List
Medical Dictionary Definitions A - Z - «M»:
Microduplication: The gain of a tiny piece of a chromosome, a piece so small its presence is not apparent on ordinary examination (using a regular light microscope to look at chromosomes prepared in the usual fashion). The detection of microduplications requires special techniques such as high-resol...
Microduplication 22q11.2 syndrome
Microduplication 22q11.2 syndrome: A syndrome due to duplication of a tiny part of chromosome band 22q11.2. Features of the syndrome include the appearance of widely spaced eyes and superior placement of eyebrows; downslanting palpebral fissures (eye slits); mild micrognathia (small chin) and retrog...
Microembolus: An embolus of microscopic size. For example, a tiny blood clot or little clump of bacteria. Like any embolus, it travels through the bloodstream, lodges in a blood vessel and blocks it....
Microhematuria: Hematuria means blood in the urine and microhematuria refers to hematuria that is visible only under a microscope. There is so little blood that it cannot be seen without magnification.
Microhematuria is in contrast to gross hematuria in which the blood is so plentiful that it is vis...
Microorchidism: Abnormally small testes. To determine if the testes are too small, a device called an orchidometer is used that permits the testes to be compared to a series of plastic ovals (like miniature American footballs) of differing sizes. Microorchidism is a diagnostic feature, for example, ...
An abnormally small penis. In medical practice, the dimension of the penis that is measured is the length. This measurement is taken along the upper surface of the shaft of the penis to the tip, using a measuring tape or, preferably, a ruler. The ruler is pressed firmly into the soft tis...
An abnormally small penis. Also called micropenis.
In medical practice, the dimension of the penis that is measured is the length. The measurement is taken along the upper surface of the shaft of the penis to the tip, using a measuring tape or
preferably a ruler. The ruler is pressed ...
Microphthalmia: An abnormally small eye, a congenital malformation (birth defect) of the globe.
The related term "anophthalmia" means no eye and refers to absence of the globe and ocular tissue from the orbit.
Microphthalmia may involve one or both eyes. It may occur in isolation with no associated...
Microphthalmia syndrome, Lenz
Microphthalmia syndrome, Lenz: See: Lenz microphthalmia syndrome....
Microscope: An optical instrument that augments the power of the eye
to see small objects. The name microscope was coined by Johannes Faber (1574-1629) who in
1628 borrowed from the Greek to combined micro-, small with skopein, to view. Although the
first microscopes were simple microscopes, most (i...
Microscope, compound: A microscope that consists of two microscopes in
series, the first serving as the ocular lens (close to the eye) and the second serving as
the objective lens (close to the object to be viewed). Credit for creating the compound
microscope goes usually to the Dutch spectaclemaker...
Microscope, electron: See: Electron microscope....
Microscope, fluorescent: See: Fluorescent microscope....
Microscope, simple: A microscope that has a single converging lens (or
a combination of lenses that function optically as a single converging lens). Anton van
Leeuwenhoek (1632-1723) made good use of the simple microscope to look at the life within
a drop of water, and such. The magnifying propertie...