| quadrigeminal rhythm | A cardiac arrhythmia in which the heartbeats are grouped in fours, each usually composed of one sinus beat followed by three extrasystoles, but a repetitive group of four of any composition is quadrigeminal. Synonym: quadrigeminy. (05 Mar 2000) |
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| anterior quadrigeminal body | The paired, larger, rounded anterior eminence of the laminae of mesencephalic tectum; major afferent connections of the superficial layers are the retina and striate cortex; input to deep layers of the colliculus are polymodal. Its efferent connections are with the lower brainstem and spinal cord (tectobulbar tract and tectospinal tract) and with the pulvinar and other cell groups in the caudal part of the thalamus; participates in extrageniculate visual pathway. Synonym: colliculus superior, anterior quadrigeminal body, corpus quadrigeminum anterius. (05 Mar 2000) |
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| posterior quadrigeminal body | The ovoid, paired, inferior eminence of the laminae of mesencephalic tectum; it receives the lateral lemniscus and projects by way of the brachium of inferior colliculus to the medial geniculate body of the thalamus, and is thus an essential way-station in the central auditory pathway. Synonym: colliculus inferior, corpus quadrigeminum posterius, inferior nasal colliculus, posterior quadrigeminal body. (05 Mar 2000) |
| superior quadrigeminal brachium | A band of fibres of the optic tract bypassing the lateral geniculate body to terminate in the superior colliculus and pretectal region. Synonym: brachium colliculi superioris, brachium quadrigeminum superius, superior quadrigeminal brachium. (05 Mar 2000) |
| quadrigeminal | Four-fold. Origin: quadri-+ L. Geminus, twin (05 Mar 2000) |
| quadrigeminal bodies | See: inferior colliculus, superior colliculus. Synonym: corpora quadrigemina. (05 Mar 2000) |
| quadrigeminal lamina | The roofplate of the mesencephalon formed by the quadrigeminal bodies. Synonym: lamina tecti mesencephali, tectum mesencephali, lamina quadrigemina, quadrigeminal lamina, quadrigeminal plate. (05 Mar 2000) |
| quadrigeminal plate | The roofplate of the mesencephalon formed by the quadrigeminal bodies. Synonym: lamina tecti mesencephali, tectum mesencephali, lamina quadrigemina, quadrigeminal lamina, quadrigeminal plate. (05 Mar 2000) |
| quadrigeminal pulse | A pulse in which the beats are grouped in fours, a pause following every fourth beat. Synonym: pulsus quadrigeminus. (05 Mar 2000) |
| inferior quadrigeminal brachium | A fibre bundle passing from the inferior colliculus on either side of the brainstem along the lateral border of the superior colliculus to the posterior part of the thalamus where it enters the medial geniculate body. It forms part of the major ascending auditory pathway. Synonym: brachium colliculi inferioris, brachium quadrigeminum inferius, inferior quadrigeminal brachium. (05 Mar 2000) |
| accelerated idioventricular rhythm | A transient and intermittent type of arrhythmia with episodes lasting from a few seconds to a minute which usually occurs in patients with acute myocardial infarction or with digitalis toxicity. Suppressive therapy is rarely necessary because the ventricular rate is generally less than 100 beats per minute. (12 Dec 1998) |
| agonal rhythm | An idioventricular rhythm, characterised by unusually wide and bizarre ventricular complexes, often seen in moribund patients. (05 Mar 2000) |
| alpha rhythm | Brain waves in the encephalogram which have a frequency of 8 to 13 per second. They are typical of the normal person awake and in a quiet resting state, and occur principally in the occipital region. (12 Dec 1998) |
| atrioventricular junctional rhythm | The cardiac rhythm when the heart is controlled by the A-V junction (including node); arising in the A-V junction, the impulse ascends to the atria and descends to the ventricles, each at varying speeds depending on site of the pacemaker. Synonym: A-V junctional rhythm, nodal bradycardia, nodal rhythm. (05 Mar 2000) |
| A-V junctional rhythm | The cardiac rhythm when the heart is controlled by the A-V junction (including node); arising in the A-V junction, the impulse ascends to the atria and descends to the ventricles, each at varying speeds depending on site of the pacemaker. Synonym: A-V junctional rhythm, nodal bradycardia, nodal rhythm. (05 Mar 2000) |
| basic electrical rhythm | A slow wave of depolarisation of smooth muscle from the fundus to the pylorus that coordinates gastric peristalsis and emptying. (05 Mar 2000) |