| extraction | The process or act of pulling or drawing out. Origin: L. Trahere = to draw (18 Nov 1997) |
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| extraction and processing industry | The industry concerned with the removal of raw materials from the earth's crust and with their conversion into refined products. (12 Dec 1998) |
| extraction coefficient | The percentage of a substance removed from the blood or plasma in a single passage through a tissue; e.g., the extraction coefficient for p-aminohippuric acid (PAH) in the kidney is the difference between arterial and renal venous plasma PAH concentrations, divided by the arterial plasma PAH concentration. (05 Mar 2000) |
| extraction, obstetrical | Extraction of the foetus by means of obstetrical instruments. (12 Dec 1998) |
| extraction ratio | The fraction of a substance removed from the blood flowing through the kidney; it is calculated from the formula (A -V)/A, where A and V, respectively, are the concentrations of the substance in arterial and renal venous plasma. (05 Mar 2000) |
| Abbe flap | A full-thickness flap of the middle portion of the lower lip that is transferred into the upper lip, or vice versa. (05 Mar 2000) |
| advancement flap | A rectangular flap raised in an elastic area, with its free end adjacent to a defect; the defect is covered by stretching the flap longitudinally until the end comes over it. Synonym: advancement flap, French flap. (05 Mar 2000) |
| arterial flap | A flap that includes a direct specific artery within its longitudinal axis. Synonym: arterial flap. (05 Mar 2000) |
| axial pattern flap | A flap that includes a direct specific artery within its longitudinal axis. Synonym: arterial flap. (05 Mar 2000) |
| bilobed flap | A flap consisting of two lobes at approximately right angles, based on a common pedicle. (05 Mar 2000) |
| bipedicle flap | A flap with two pedicles, one at each end. Synonym: double pedicle flap. (05 Mar 2000) |
| bone flap | Portion of cranium removed but left attached to overlying soft tissue structures. (05 Mar 2000) |
| buried flap | A flap denuded of both surface epithelium and superficial dermis and transferred into the subcutaneous tissues. (05 Mar 2000) |
| capsular flap pyeloplasty | A reconstructive procedure for correction of uteropelvic obstruction, whereby a flap of renal capsule is swung down from the renal hilus to enlarge an obstructed intrarenal pelvis and upper ureter; used to correct situations involving loss of renal pelvic tissue which preclude the use of renal pelvis for the reconstruction. (05 Mar 2000) |
| random pattern flap | A flap in which the pedicle blood supply is derived randomly from the network of vessels in the area, rather than from a single longitudinal artery as in an axial pattern flap. (05 Mar 2000) |