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Home  »  Anatomy of the Human Body  »  pages 769

Henry Gray (1825–1861). Anatomy of the Human Body. 1918.

pages 769

The remaining fibers—i. e., those which occupy the lateral part of the pyramid—do not cross the middle line, but are carried downward as the anterior cerebrospinal fasciculus (Fig. 680) into the anterior funiculus of the same side.
  The greater part of the anterior proper fasciculus of the medulla spinalis is continued upward through the medulla oblongata under the name of the medial longitudinal fasciculus.


FIG. 681– Hind- and mid-brains; postero-lateral view. (See enlarged image)
  The lateral district (Fig. 681) is limited in front by the antero-lateral sulcus and the roots of the hypoglossal nerve, and behind by the postero-lateral sulcus and the roots of the accessory, vagus, and glossopharyngeal nerves. Its upper part consists of a prominent oval mass which is named the olive, while its lower part is of the same width as the lateral funiculus of the medulla spinalis, and appears on the surface to be a direct continuation of it. As a matter of fact, only a portion of the lateral funiculus is continued upward into this district, for the lateral cerebrospinal fasciculus passes into the pyramid of the opposite side, and the dorsal spinocerebellar fasciculus is carried into the inferior peduncle in the posterior district. The ventral spinocerebellar fasciculus is continued upward on the lateral surface of the medulla oblongata in the same relative position it occupies in the spinal cord until it passes under cover of the external arcuate fibers. It passes beneath these fibers just dorsal to the olive and ventral to the roots of the vagus and glossopharyngeal nerves; it continues upward through the pons along the dorso-lateral edge of the lateral lemniscus. The remainder of the lateral funiculus consists chiefly of the lateral proper fasciculus. Most of these fibers dip beneath the olive and disappear from the surface; but a small strand remains superficial to the olive. In a depression at the upper end of this strand is the acoustic nerve.
  The olive (oliva; olivary body) is situated lateral to the pyramid, from which it is separated by the antero-lateral sulcus, and the fibers of the hypoglossal nerve. Behind, it is separated from the postero-lateral sulcus by the ventral spinocerebellar fasciculus. In the depression between the upper end of the olive and the pons lies the acoustic nerve. It measures about 1.25 cm. in length, and between its upper