matrix

1. [NA] The formative portion of a tooth or a nail. 2. The intercellular substance of a tissue. 3. A surrounding substance within which something is contained or embedded, e.g., the fatty tissue in which blood vessel s or lymph node s lie; provides a m. for these embedded structures. 4. A mold in which anything is cast or swaged; a counterdie; a specially shaped instrument, plastic material, or metal strip used for holding and shaping the material used in filling a tooth cavity. 5. A rectangular array of numbers or symbol quantities that simplify the execution of linear operations of tedious complexity, e.g., the ITO method; the theory of matrices is widely used in solving simultaneous equations and in population genetics. [L. womb; female breeding animal]

- amalgam m. a device used during placement of the amalgam mass within a compound cavity preparation, facilitating proper condensation and contour thereof by providing a confining wall.

- bone m. the intercellular substance of bone tissue consisting of collagen fibers, ground substance, and inorganic bone salts.

- cartilage m. the intercellular substance of cartilage consisting of fibers and ground substance.

- cell m. SYN: cytoplasmic m..

- cytoplasmic m. a fluid cytoplasmic substance filling the interstices of the cytoskeleton. SYN: cell m., cytomatrix.

- external m. the substance occupying the space between the inner and outer membrane of any organelle ( E.G., mitochondria) with a double membrane.

- identity m. a square m. in which the quantities on the diagnonal from top left to bottom right are all equal to 1 and all the other entries are 0.

- mitochondrial m. SYN: m. mitochondrialis.

- m. mitochondrialis the substance occupying the space enclosed by the inner membrane of a mitochondrion; it contains enzymes, filaments of DNA, ribosomes, granules, and inclusions of protein crystals, glycogen, and lipid. SYN: mitochondrial m..

- nail m. [TA] the area of the corium on which the nail rests; it is extremely sensitive and presents numerous longitudinal ridges on its surface. According to some anatomists, the nail bed is the portion covered by the body of the nail, the nail bed being only the part on which the root of the nail rests. SYN: m. unguis [TA], keratogenous membrane, nail bed, onychostroma.

- nuclear m. the network of protein fibers both around the outside of the nucleus as well as inside the nucleus.

- square m. a m. in which the numbers of rows and columns are equal.

- territorial m. SYN: cartilage capsule.

- m. unguis [TA] SYN: nail m..

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ma·trix 'mā-triks n, pl ma·tri·ces 'mā-trə-.sēzalso 'ma- or matrixes

1 a) the extracellular substance in which tissue cells (as of connective tissue) are embedded <mineralization of bone \matrix>

b) the thickened epithelium at the base of a fingernail or toenail from which new nail substance develops called also nail bed, nail matrix

2) something (as a surrounding or pervading substance or element) within which something else originates or takes form or develops

3) a mass by which something is enclosed or in which something is embedded <membrane-bound organelles suspended in the cytoplasmic \matrix> <chromatin fibers attach to the nuclear \matrix>

4 a) a strip or band placed so as to serve as a retaining outer wall of a tooth in filling a cavity

b) a metal or porcelain pattern in which an inlay is cast or fused

5) the substrate on or within which a fungus grows

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n.

1. (in histology) the substance of a tissue or organ in which more specialized structures are embedded; for example, the ground substance of connective tissue.

2. (in radiology) the division of an image into rows and columns with equally sized elements (pixel). The final image is completed by assigning a density to each of these elements. Increasing the number of pixels in the matrix improves the resolution of the final image. A typical value could be 256 rows x 256 columns.

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ma·trix (maґtriks) pl. maґtrices [L.] 1. the intracellular substance of a tissue or the tissue from which a structure develops. 2. the groundwork on which anything is cast, or that basic material from which a thing develops. 3. a mold or a form for casting. 4. a plastic or metal strip used to support and shape a plastic restorative material. 5. a piece of gold or platinum foil fitted against the sides and bottom of a cavity, used as a mold in which porcelain for an inlay is baked. 6. resin m. 7. term used for the feldspar component of dental porcelain, which provides a glassy matrix in which quartz particles are dispersed.