A manual of anatomy . medianlongitudinal furrow and is dividedinto upper and lower triangles bysome nerve fibers that cross the middle of the space transverselyto pass into the median furrow; these fibers, the acoustic stricR{strice medullaris) may be absent, but when present approximatelyseparate the oblongatal part of the ventricle from the tegmental,or pontile potion. In the upper triangle near the midline and the acoustic stria isan eminence, the colliculus facialis {eminentia mediana); just belowand lateral is a depressed area, the superior fovea. Above the emi-nence, toward the apex of t
A manual of anatomy . medianlongitudinal furrow and is dividedinto upper and lower triangles bysome nerve fibers that cross the middle of the space transverselyto pass into the median furrow; these fibers, the acoustic stricR{strice medullaris) may be absent, but when present approximatelyseparate the oblongatal part of the ventricle from the tegmental,or pontile potion. In the upper triangle near the midline and the acoustic stria isan eminence, the colliculus facialis {eminentia mediana); just belowand lateral is a depressed area, the superior fovea. Above the emi-nence, toward the apex of the triangle, is a slate-colored, slightlydepressed area, the locus cceruleus; the cells in this area are pig-mented by the substantia ferruginea. In the lower triangle just below the acoustic striae is the area acus-tica (better area vestibularis). Medially and below this is a triangu-lar depression, the trigonum vagi {ala cinerea) and between this andthe median groove is seen a tapering elevation, the trigonum hypo-. FlG. -The so-called floorfourth ventricle. THE MIDBRAIN 379 glossi. These tapering elevations, at the lower angle of the ventricle,constitute the calamus scriptorius (point of a pen). Between the lower margin of the trigonum vagi and the lowerboundary of the ventricle is a narrow space, the area postrema; thisis separated from the trigonum vagi by the funiculus separans, aclear ridge. The lower lateral boundaries of the fourth ventricle are the diverg-ing restiform bodies; at the lateral angles are the two middle pedun-cles; the upper lateral boundaries are the converging superiorpeduncles that also form a small part of the roof in this region. The fourth ventricle communicates caudally with the spinal canaland above it is continuous with the aqueduct of Sylvius, or iter. Itrepresents a lymph space and communicates with the subarach-noid space by means of an opening in the roof of the lower triangle,the foramen of Majendie. The roof at the lateral angles pos
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Keywords: ., bookcentury1900, bookdecade1910, booksubjecthumananatomy, bookyea
