. Anatomy, descriptive and applied. Anatomy. 894 THE NERVE SYSTEM gemina, the internal geniculate bodies, and the aqueduct. Its two surfaces are ven- tral and dorsal. They are free, but concealed; the ventral surface by the apices of the temporal lobes which overlap it; the dorsal, by the overhanging cerebral hemi- spheres. The ventral surface, when exposed by drawing aside the temporal lobes, is seen to consist of two cylindrical bundles of white substance, which emerge from the pons and diverge as they pass forward and outward, to enter the inner and under part of either hemisphere. They are
. Anatomy, descriptive and applied. Anatomy. 894 THE NERVE SYSTEM gemina, the internal geniculate bodies, and the aqueduct. Its two surfaces are ven- tral and dorsal. They are free, but concealed; the ventral surface by the apices of the temporal lobes which overlap it; the dorsal, by the overhanging cerebral hemi- spheres. The ventral surface, when exposed by drawing aside the temporal lobes, is seen to consist of two cylindrical bundles of white substance, which emerge from the pons and diverge as they pass forward and outward, to enter the inner and under part of either hemisphere. They are the crura cerebri, and between them is a triangular area, the intercfural space;' near the point of divergence of the crura cerebri the roots of the third nerve are seen to emerge in several bundles from a groove, the sulcus oculomotorius (sulcus nervi oculomotorii) (Fig. 619). The dorsal surface is not visible until a considerable portion of the cerebral hemi- spheres and other overlying structures have been removed. It then presents four rounded eminences placed in pairs, two cephalad and two caudad, and sepa- rated from one another by a crucial depression. These are termed the corpora. FRENULUM-- ' -^..r-TAENlA PONTIS TROCHLEAR NERVe' ^B TRIGEMINAL NERVE SUPERIOR MEDULLAR ^/^^^ VELUM (cut) ^^^ 1ERVE USTIC NERVE RESTIFORM BODY ^ ^±J ^iHBI^3^ GLOSSOPHARYNGEAL AND VAGUS NERVES CUNEATC TUBERCLE -^' Wi--^^^^^S/^ HYPOGLOSSAL NERVE TUBERCULUM CINEREUIV Fig. 662.—The brain stem, showing medulla oblongata, pons, mid-brain, and part of- the optic thalami. quadrigemina (Fig. 662). The ventral and dorsal surfaces meet on the side of the mid-brain, and are separated from each other by a furrow, the lateral groove {sulcus lateralis viesencejjhali), which runs caudocephalad (Fig. 662). External Morphology. Dorsal Surface.—The corpora quadrigemina are four rounded eminences placed in pairs separated by a shallow median groove and a more sharply cut transverse-furrow. The cephalic pair
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
