The encyclopdia britannica; a dictionary of arts, sciences, literature and general information . m, which is acontinuation upward of the formatio reticularis of the medulla,and passing through it are seen three important nerve superior cerebellar peduncle is the most internal of these anddecussates with its fellow of the opposite side so that the two teg-menta are continuous across the middle line. More externally themesial fillet is seen, while dorsal to the cerebellar peduncle is theposterior longitudinal bundle. If the section happens to passthrough the superior corpus quadrigem
The encyclopdia britannica; a dictionary of arts, sciences, literature and general information . m, which is acontinuation upward of the formatio reticularis of the medulla,and passing through it are seen three important nerve superior cerebellar peduncle is the most internal of these anddecussates with its fellow of the opposite side so that the two teg-menta are continuous across the middle line. More externally themesial fillet is seen, while dorsal to the cerebellar peduncle is theposterior longitudinal bundle. If the section happens to passthrough the superior corpus quadrigeminum a characteristic circulararea appears between the cerebellar peduncle and the fillet, which,from its tint, is called the red nucleus. More dorsally still the sectionwill pass through the Sylvianaqueduct or passage from the third tothe fourth ventricle, and this is surrounded by a mass of grey matterin the ventral part of which are the nuclei of the third and fourth 39^ BRAIN [ANATOMY External geniculatebody* Inferior brachium Internal genictilatebody Mesial fillet Crusta Optic tract ?. From Cunningham, Text-hook oj Anatomy. Fig. 8.—Transverse Section through the Human Mesencephalon at the level of thesuperior Quadrigeminal Body. nerves. The third nerve is seen at the level ofi;he superior corpusquadrigeminum running from its nucleus of origin, through the rednucleus, to a groove on the inner side of the crus called the octilo-motor groove, which marks the separation between the crusta andtegmentum. Dorsal to the Sylvian aqueduct is a layer called thelamina quadrigemina and on this the corpora quadrigemina superior pair of these bodies is overlappedby the pineal body and forms part of the lowervisual centres. Connexions can be traced to theoptic tract, the higher visual centre on the mesialsurface of the occipital lobe, the deep origin ofthe third or oculo-motor nerve as well as to themesial and lateral fillet. The inferior pair ofquadrigeminal bodies are more cl
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectencyclo, bookyear1910
