. The anatomy of the human body. Human anatomy; Anatomy. THE MEDULLA OBLONGATA, ETC. 703- breadth, and six in thickness ; it is therefore much broader and thicker than the spinal cord. The medulla oblongata is directed obhquely, like the inclined plane of the basilar groove, so that it forms with the spinal cord a very obtuse angle, which projects back- ward. In shape it resembles a cone flattened in front and behind, and having its base turned upward and its apex downward; it has, therefore, four surfaces, viz., an anterior, a pos- terior, and two lateral. Anterior Surface of the Medulla Oblo
. The anatomy of the human body. Human anatomy; Anatomy. THE MEDULLA OBLONGATA, ETC. 703- breadth, and six in thickness ; it is therefore much broader and thicker than the spinal cord. The medulla oblongata is directed obhquely, like the inclined plane of the basilar groove, so that it forms with the spinal cord a very obtuse angle, which projects back- ward. In shape it resembles a cone flattened in front and behind, and having its base turned upward and its apex downward; it has, therefore, four surfaces, viz., an anterior, a pos- terior, and two lateral. Anterior Surface of the Medulla Oblongata. ? "J- This surface {fig. 270) is directed downward, and is therefore named inferior by some anatomists ; it is convex, and is lodged in the basilar groove of the occipital bone; it can be properly examined only after its neurilemma has been dissected oflT, which is easily done, because its substance is denser than the spinal cord. On this surface we observe a median furrow (/), into which numerous vessels enter : this furrow, which is not nearly so deep as the anterior median furrow of the spinal oord, with which it is continuous, is interrupted by a decussation of fibres about ten lines below the pons Varolii (below n), and terminates above in a tolerably deep fossa {Ic trou borgne, or foramen ccecum, of Vicq d'Azyr), at the point where the furrow meets the pons. Not un- frequently some transverse fibres occupy the place of this median furrow, in which case the anterior surface of the medulla ob- longata resembles the pons Varohi; sometimes these transverse fibres are found upon only a part of the medulla oblongata. On each side of this median furrow are seen two eminences, which seem as if mould ? ed in relief upon the part, and which form two planes, succeeding one another like steps from within outward. The two internal eminences are called the anterior pyramids; the two external are named, from their shape, the olivary bodies. The interior Pyramids. The anterio
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Keywords: ., boo, bookcentury1800, booksubjectanatomy, booksubjecthumananatomy
