. Cunningham's Text-book of anatomy. Anatomy. INTERNAL STRUCTURE OF THE MESENCEPHALON. 589 Decussating fibres Nucleus of inferior colliculus Mesencephalic root of tri- geminal nerve Trochlear nerve Medial longitudinal bundle Lateral lemniscus Brachium conjunctivum Medial lemniscus important functions of this strand is to bind together these nuclei, and thus enable them to act in harmony one with the other. Fibres also enter the medial longitudinal fasciculus from the vestibular nucleus of the acoustic nerve system. The results obtained by degeneration would seem to indicate that, to a large ex
. Cunningham's Text-book of anatomy. Anatomy. INTERNAL STRUCTURE OF THE MESENCEPHALON. 589 Decussating fibres Nucleus of inferior colliculus Mesencephalic root of tri- geminal nerve Trochlear nerve Medial longitudinal bundle Lateral lemniscus Brachium conjunctivum Medial lemniscus important functions of this strand is to bind together these nuclei, and thus enable them to act in harmony one with the other. Fibres also enter the medial longitudinal fasciculus from the vestibular nucleus of the acoustic nerve system. The results obtained by degeneration would seem to indicate that, to a large extent, it is formed of fibres which run a short course within it. That it is a brain tract of high importance, is evident from the fact that it is present in all vertebrates, and, further, that its fibres assume their medullary sheaths at an extremely early period. In fishes, amphibians, and reptiles, it is one of the largest bundles of the medulla oblongata. In man, its fibres medullate between the sixth and seventh months of foetal life, and at the same time as the fibres of the fasciculus anterior proprius of the spinal medulla, with which it stands in connexion. According to van Gehuchten and Edinger, it extends upwards beyond the level of the oculomotor nucleus, and in the thalamic region its fibres take origin from a special nucleus of its own in the gray matter of the third ventricle, im- mediately behind the level of the corpora mamillaria. Fibres also enter the medial longitudinal bundle from a nucleus common to it and the posterior commissure of the brain. This nucleus is placed in the fore part of the central gray matter of the mid-brain. Held asserts that numerous fibres, aris- ing from cells in the superior col- liculus, curve in an arcuate manner in the tegmentum outside the cen- tral gray matter, to take part on the ventral aspect of this in what is called the fountain decussation. Reaching the opposite side, these fibres turn downwards and join the medial longitu
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
