| Descartes' law | For two given media, the sine of the angle of incidence bears a constant relation to the sine of the angle of refraction. Synonym: Descartes' law, Snell's law. (05 Mar 2000) |
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| Descartes, Rene | <person> French philosopher, mathematician, physiologist, 1596-1650. The founder of modern philosophy and proponent of the mechanistic school or iatromathematical school. See: Descartes' law. (05 Mar 2000) |
| descemet's membrane | The strong, resistant, thin, noncellular fourth layer of the cornea, located between the endothelium (from which it is secreted) and the stroma. (12 Dec 1998) |
| Descemet, Jean | <person> French physician, 1732-1810. See: Descemet's membrane. (05 Mar 2000) |
| descemetitis | Inflammation of Descemet's membrane. (05 Mar 2000) |
| descemetocele | A bulging forward of Descemet's membrane caused by the destruction of the substance of the cornea by infection. (05 Mar 2000) |
| descend | 1. To pass from a higher to a lower place; to move downwards; to come or go down in any way, as by falling, flowing, walking, etc.; to plunge; to fall; to incline downward; the opposite of ascend. "The rain descended, and the floods came." (Matt. Vii. 25) "We will here descend to matters of later date." (Fuller) 2. To enter mentally; to retire. "[He] with holiest meditations fed, Into himself descended." (Milton) 3. To make an attack, or incursion, as if from a vantage ground; to come suddenly and with violence; with on or upon. "And on the suitors let thy wrath descend." (Pope) 4. To come down to a lower, less fortunate, humbler, less virtuous, or worse, state or station; to lower or abase one's self; as, he descended from his high estate. 5. To pass from the more general or important to the particular or less important matters to be considered. 6. To come down, as from a source, original, or stock; to be derived; to proceed by generation or by transmission; to fall or pass by inheritance; as, the beggar may descend from a prince; a crown descends to the heir. 7. <anatomy> To move toward the south, or to the southward. 8. To fall in pitch; to pass from a higher to a lower tone. Origin: F. Descendre, L. Descendere, descensum; de- + scandere to climb. See Scan. Source: Websters Dictionary (01 Mar 1998) |
| descendens | Synonym: descending. Origin: L. (05 Mar 2000) |
| descendens cervicalis | Fibres from the second and third cervical nerves that pass forward and downward along the internal jugular vein; they contribute to the ansa cervicalis and innervate the infrahyoid muscles. Synonym: descendens cervicalis, radix inferior ansae cervicalis. (05 Mar 2000) |
| descendens hypoglossi | The fibres that arise from the first and second cervical nerves, accompany the hypoglossal nerve, then branch off to meet the inferior root in the ansa cervicalis; they innervate the infrahyoid muscles. Synonym: descendens hypoglossi, descending branch of hypoglossal nerve, radix superior ansae cervicalis. (05 Mar 2000) |
| descending | Of or pertaining to descent; moving downwards. <astronomy> Descending constellations or signs, that point in a planet's orbit where it intersects the ecliptic in passing southward. <mathematics> Descending series, a series in which each term is numerically smaller than the preceding one; also, a series arranged according to descending powers of a quantity. Source: Websters Dictionary (01 Mar 1998) |
| descending anterior branch | The descending anterior branch of the superior lobar branches of the right and left pulmonry arteries. Synonym: ramus anterior descendens. (05 Mar 2000) |
| descending aorta | A part of the aorta, further divided into the thoracic aorta and the abdominal aorta. Synonym: pars descendens aortae, aorta descendens, descending part of aorta. (05 Mar 2000) |
| descending artery of knee | <anatomy, artery> Origin, femoral, in adductor canal; distribution, penetrates vastoadductor fascia to supply knee joint and adjacent parts; anastomoses, medial superior genicular, medial inferior genicular, lateral superior genicular, lateral inferior genicular and anterior tibial recurrent arteries, i.e., articular network of knee. Synonym: arteria genus descendens, arteria anastomotica magna, descending artery of knee, great anastomotic artery. (05 Mar 2000) |
| descending branch | Branch of an artery or nerve passing inferiorly. Descending branches have been described for the following: descending branch of hypoglossal nerve, superior root of ansa cervicalis; descending branch of lateral circumflex femoral artery; descending branch of the occipital artery. Synonym: ramus descendens. (05 Mar 2000) |