| release phenomenon | The increased tonus and hyperirritability of muscle-stretch reflexes which occur following damage of the upper portions of the extrapyramidal system. (05 Mar 2000) |
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| Glover phenomenon | Nonrandom (i.e., haphazard) variation among communities in rates of performing common elective procedures, such as tonsillectomy, hysterectomy, attributable to local variations in medical and surgical practices. (05 Mar 2000) |
| Goldblatt phenomenon | Increased blood pressure following obstruction of blood flow to one kidney. Synonym: Goldblatt phenomenon. (05 Mar 2000) |
| cervicolumbar phenomenon | A sense of weakness in the lower extremities on movement of the neck when a lesion is present in the upper portion of the spinal cord; or sensations referred to the neck when a lesion exists in the lower portion of the cord. (05 Mar 2000) |
| Grasset-Gaussel phenomenon | In organic paralysis of the lower extremity, the patient, lying on his back, can raise either limb separately, but not both together. Synonym: Grasset-Gaussel phenomenon. (05 Mar 2000) |
| Grasset's phenomenon | In organic paralysis of the lower extremity, the patient, lying on his back, can raise either limb separately, but not both together. Synonym: Grasset-Gaussel phenomenon. (05 Mar 2000) |
| peroneal phenomenon | Tapping the peroneal nerve below the head of the fibula causes dorsiflexion and abduction of the foot. (05 Mar 2000) |
| Ritter-Rollet phenomenon | On equal electrical stimulation of motor nerve trunks, the flexor and abductor muscle groups react more readily than the extensors and adductors. (05 Mar 2000) |
| Pfeiffer's phenomenon | The alteration and complete disintegration of cholera vibrios when introduced into the peritoneal cavity of an immunised guinea pig, or into that of a normal one if immune serum is injected at the same time; extended to include bacteriolysis in general. (05 Mar 2000) |
| Gunn phenomenon | <syndrome> An increase in the width of the eye lids during chewing, sometimes with a rhythmic elevation of the upper lid when the mouth is open and ptosis when the mouth is closed. Synonym: Gunn phenomenon, Gunn's syndrome, jaw-winking phenomenon, jaw-working reflex, Marcus Gunn phenomenon, Marcus Gunn syndrome. (05 Mar 2000) |
| R-on-T phenomenon | A premature ventricular (QRS) complex in the electrocardiogram interrupting the T wave of the preceding beat; often predisposes to serious ventricular arrhythmias. (05 Mar 2000) |
| phenomenon | Origin: L. Phaenomenon, Gr. Fainomenon, fr. Fainesqai to appear, fainein to show. See Phantom. 1. An appearance; anything visible; whatever, in matter or spirit, is apparent to, or is apprehended by, observation; as, the phenomena of heat, light, or electricity; phenomena of imagination or memory. "In the phenomena of the material world, and in many of the phenomena of mind." (Stewart) 2. That which strikes one as strange, unusual, or unaccountable; an extraordinary or very remarkable person, thing, or occurrence; as, a musical phenomenon. Source: Websters Dictionary (01 Mar 1998) |
| phi phenomenon | An illusion of movement, which occurs by means of successive visual impressions at intervals of 1/15 to 1/20 sec; when an occluder is passed from one eye to the other while a small distant light is observed, the light seems to move with the occluder in exophoria, but in an opposite direction in oesophoria. (05 Mar 2000) |
| Rumpel-Leede phenomenon | Appearance of petechiae in an area following application of vascular constriction, such as by a tourniquet, usually after 10 minutes but can appear after shorter period, such as following application of tourniquet to draw blood specimen or use of blood pressure cuff. Due to capillary fragility or abnormal platelet numbers (e.g. Thrombocytopenia) or function. (05 Mar 2000) |
| Rust's phenomenon | In cancer or caries of the upper cervical vertebrae, the patient will always support the head by the hands when changing from the recumbent to the sitting posture or the reverse. (05 Mar 2000) |