| block book | A book printed from engraved wooden blocks instead of movable types. Source: Websters Dictionary (01 Mar 1998) |
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| block design test | A performance test using coloured blocks which the individual must use to match pictured designs; one of the subtests of the Wechsler intelligence scales. (05 Mar 2000) |
| block-out | Elimination of undercuts by filling such areas with a medium such as wax or wet pumice. (05 Mar 2000) |
| block vertebra | <radiology> Congenital vertebral fusion, location: lumbar or cervical, height of the fused vertebral bodies equals the sum of heights of the involved bodies and intervertebral disc, waist at level of disc space see: cervical spine fusion (12 Dec 1998) |
| block vertebrae | Congenitally fused and hypoplastic vertebral bodies which, on radiographs, give the appearance of a more or less solid bony mass. See: Klippel-Feil syndrome. (05 Mar 2000) |
| bone block | A surgical procedure in which the bone adjacent to the joint is modified to limit the motion of the joint mechanically; e.g., at the ankle joint to correct foot-drop by preventing extension below 90 |
| paracervical block anaesthesia | Regional anaesthesia of the cervix uteri by injection of local anaesthetic solution into tissues adjacent to the cervix. (05 Mar 2000) |
| genetic block | <biochemistry, molecular biology> An obstruction in a biochemical pathway caused by a mutation that has crippled production of an enzyme critical to the pathway. (07 May 1998) |
| partial heart block | Impulses penetrate the atrioventricular junction in some relation to the ventricular rate. Synonym: incomplete atrioventricular block. (05 Mar 2000) |
| retrograde block | Impaired conduction backward from the ventricles or A-V node into the atria. (05 Mar 2000) |
| peri-infarction block | An electrocardiographic abnormality associated with an old myocardial infarct and caused by delayed activation of the myocardium in the region of the infarct; characterised by an initial vector directed away from the infarcted region with the terminal vector directed toward it. (05 Mar 2000) |
| phase I block | Inhibition of nerve impulse transmission across the myoneural junction associated with depolarisation of the motor endplate, as in the muscle paralysis produced by succinylcholine. (05 Mar 2000) |
| phase II block | Inhibition of nerve impulse transmission across the myoneural junction unaccompanied by depolarisation of the motor endplate, as in the muscle paralysis produced by tubocurarine. (05 Mar 2000) |
| Mobitz block | Second degree atrioventricular block in which there is a ratio of two or more atrial deflections (P waves) to ventricular responses. Mobitz types of atrioventricular block, type I, the dropped beat of the Wenckebach phenomenon; type II, a dropped cardiac cycle that occurs without alteration in the conduction of the preceding intervals. (05 Mar 2000) |
| Wenckebach block | A form of block in any cardiac tissue (most often the atrioventricular junction) in which there is progressive lengthening of conduction until the beat is dropped. (05 Mar 2000) |