| OCS | occipital condyle syndrome; Ondine's curse syndrome; open canalicular system; oral contraceptive ste... |
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| OD | Doctor of Optometry; obtained absorbance; occipital dysplasia; occupational dermatitis; occupational... |
| OFD | object-film distance; occipital frontal diameter; oro-facial-digital [syndrome] |
| OH | hydroxycorticosteroid; obstructive hypopnea; occipital horn; occupational health; occupational histo... |
| OHS | obesity hypoventilation syndrome; occipital Horn syndrome; occupational health service; ocular histo... |
| block anaesthesia | Regional anaesthesia in which local anaesthetic solution is injected about nerves to inhibit nerve transmission; includes spinal, epidural, nerve block, and field block anaesthesia, but not local or topical anaesthesia. Synonym: block anaesthesia. (05 Mar 2000) |
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| block book | A book printed from engraved wooden blocks instead of movable types. Source: Websters Dictionary (01 Mar 1998) |
| 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 |
| bundle-branch block | <cardiology, physiology> Abnormal conduction through one of the conductive branches which normally supply the right and left ventricles. Usually results in delayed conduction though either the right or left bundle branches where one ventricle is excited before the other because of absence of conduction in one of the branches of the bundle of His. Intraventricular block due to interruption of conduction in one of the two main branches of the bundle of His and manifested in the electrocardiogram by marked prolongation of the QRS complex; block of each branch has distinctive QRS morphology. (05 Mar 2000) |
| 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) |