| his bundle electrography | <investigation> This test studies the electrical activity of the bundle of HIS. The bundle of HIS is a group of electrical fibres in the heart that are responsible for transmitting the electrical impulses which generate a normal cardiac contraction. This test may be performed in cases of cardiac arrhythmias, to locate a specific area responsible for a conduction defect and to determine the need for cardiac pacemaker placement. The test involves the passage of a an electrode tipped catheter into the heart. This catheter is usually threaded through a neck, arm or chest vein. Measurements of the HIS bundle can then be performed while standard ECG leads are placed on the arms and legs. This test carries a small risk of bleeding, arrhythmias, embolism, heart attack and stroke. It is performed by a specially trained cardiologist. (27 Sep 1997) |
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| his bundle studies | <cardiology> This test studies the electrical activity of the bundle of HIS. The bundle of HIS is a group of electrical fibres in the heart that are responsible for transmitting the electrical impulses which generate a normal cardiac contraction. This test may be performed in cases of cardiac arrhythmias, to locate a specific area responsible for a conduction defect and to determine the need for cardiac pacemaker placement. The test involves the passage of a an electrode tipped catheter into the heart. This catheter is usually threaded through a neck, arm or chest vein. Measurements of the HIS bundle can then be performed while standard ECG leads are placed on the arms and legs. This test carries a small risk of bleeding, arrhythmias, embolism, heart attack and stroke. It is performed by a specially trained cardiologist. (27 Sep 1997) |
| Hoche's bundle | A compact bundle composed of descending branches of posterior root fibres located near the border between the fasciculi gracilis and cuneatus of the cervical and thoracic spinal cord; it corresponds to the septomarginal fasciculus, Hoche's tract, or oval area of Flechsig in the lumbar, and to the triangle of Philippe-Gombault in the sacral spinal segments; like these, it can be demonstrated only in cases of demyelination resulting from dorsal root lesions. Synonym: fasciculus semilunaris, fasciculus interfascicularis, comma bundle of Schultze, comma tract of Schultze, interfascicular fasciculus. (05 Mar 2000) |
| hooked bundle of Russell | Fastigial efferent fibres that cross with the cerebellum and descend over the lateral surface of the superior cerebellar peduncle; these fibres largely terminate in the vestibular nuclei and the reticular formation of the pons and medulla. Synonym: hooked bundle of Russell, uncinate fasciculus of Russell. (05 Mar 2000) |
| solitary bundle | A slender, compact fibre bundle extending longitudinally through the dorsolateral region of the medullary tegmentum, surrounded by the nucleus of the solitary tract, below the obex decussating over the central canal, and descending over some distance into the upper cervical segments of the spinal cord. It is composed of primary sensory fibres that enter with the vagus, glossopharyngeal, and facial nerves, and in part convey information from stretch receptors and chemoreceptors in the walls of the cardiovascular, respiratory, and intestinal tracts; in rostral parts of the tract impulses are generated by the receptor cells of the taste buds in the mucosa of the tongue. Its fibres are distributed to the nucleus of the solitary tract. Synonym: tractus solitarius, fasciculus rotundus, fasciculus solitarius, funiculus solitarius, Gierke's respiratory bundle, Krause's respiratory bundle, round fasciculus, solitary bundle, solitary fasciculus. (05 Mar 2000) |
| oblique bundle of pons | A bundle of fibres in the ventral surface of the pons running from the anterior mesial portion outward and backward. Synonym: fasciculus obliquus pontis, oblique bundle of pons. (05 Mar 2000) |
| olfactory bundle | A fibre system, described by E. Zuckerkandl as "Reichbundel," descending from the transparent septum in front of the anterior commissure toward the base of the forebrain; it contains precommissural fibres of the fornix, fibres from the septum to the hypothalamus and innominate substance, as well as fibres ascending to the septum and hippocampus from the hypothalamus and midbrain; it bears no special relation to the sense of smell. (05 Mar 2000) |
| olivocochlear bundle | A bundle of fibres that originates from the periolivary nuclei bilaterally, exits the brainstem on the vestibular nerve, joins the cochlear nerve in the inner ear, and terminates on outer hair cells. Synonym: bundle of Rasmussen, olivocochlear fibres. (05 Mar 2000) |
| tendon bundle | A group of tendon fibres surrounded by a sheath of irregular connective tissue (peritendineum). (05 Mar 2000) |
| trunk of atrioventricular bundle | The singular initial portion (stem) of the atrioventricular bundle which passes from the atrioventricular node into the right trigone of the fibrous skeleton of the heart and along the periphery of the membranous interventricular septum; upon reaching the muscular interventricular septum, the trunk terminates by dividing into the right and left crura of the atrioventricular bundle. Synonym: truncus fascicularis atrioventricularis. (05 Mar 2000) |
| Turck's bundle | Uncrossed fibres forming a small bundle in the pyramidal tract. See: pyramidal tract. Synonym: tractus corticospinalis anterior, tractus pyramidalis anterior, anterior corticospinal tract, anterior pyramidal fasciculus, direct pyramidal tract, fasciculus corticospinalis anterior, fasciculus pyramidalis anterior, Turck's bundle, Turck's column, Turck's tract. (05 Mar 2000) |
| Keith's bundle | The bundle of modified cardiac muscle fibres that begins at the atrioventricular node as the trunk of the atrioventricular bundle and passes through the right atrioventricular fibrous ring to the membranous part of the interventricular septum where the trunk divides into two branches, the right crus of the atrioventricular bundle and the left crus of the atrioventricular bundle; the two crura ramify in the subendocardium of their respective ventricles. Synonym: fasciculus atrioventricularis, atrioventricular band, Gaskell's bridge, His' band, His' bundle, bundle of His, Keith's bundle, Kent's bundle, Kent-His bundle, ventriculonector. (05 Mar 2000) |
| Kent-His bundle | The bundle of modified cardiac muscle fibres that begins at the atrioventricular node as the trunk of the atrioventricular bundle and passes through the right atrioventricular fibrous ring to the membranous part of the interventricular septum where the trunk divides into two branches, the right crus of the atrioventricular bundle and the left crus of the atrioventricular bundle; the two crura ramify in the subendocardium of their respective ventricles. Synonym: fasciculus atrioventricularis, atrioventricular band, Gaskell's bridge, His' band, His' bundle, bundle of His, Keith's bundle, Kent's bundle, Kent-His bundle, ventriculonector. (05 Mar 2000) |
| Kent's bundle | The bundle of modified cardiac muscle fibres that begins at the atrioventricular node as the trunk of the atrioventricular bundle and passes through the right atrioventricular fibrous ring to the membranous part of the interventricular septum where the trunk divides into two branches, the right crus of the atrioventricular bundle and the left crus of the atrioventricular bundle; the two crura ramify in the subendocardium of their respective ventricles. Synonym: fasciculus atrioventricularis, atrioventricular band, Gaskell's bridge, His' band, His' bundle, bundle of His, Keith's bundle, Kent's bundle, Kent-His bundle, ventriculonector. (05 Mar 2000) |
| uncinate bundle of Russell | Fastigial efferent fibres that cross with the cerebellum and descend over the lateral surface of the superior cerebellar peduncle; these fibres largely terminate in the vestibular nuclei and the reticular formation of the pons and medulla. Synonym: hooked bundle of Russell, uncinate fasciculus of Russell. (05 Mar 2000) |