. Cunningham's Text-book of anatomy. Anatomy. 1040 THE VASCULAE SYSTEM. anterior cerebral vein atrophy in the middle parts of their lengths. The npper portions then become the superior cerebral veins, which terminate in the sujjerior sagittal sinus, and the lower portions become the inferior cerebral veins. These open into the primitive anterior cerebral vein which lies in the lateral fissure of the hemisj)here and becomes the medial cerebral vein of the adult. Very commonly one of the intercommunicating tributaries persists in the whole of its length and so becomes the great anastomotic vein
. Cunningham's Text-book of anatomy. Anatomy. 1040 THE VASCULAE SYSTEM. anterior cerebral vein atrophy in the middle parts of their lengths. The npper portions then become the superior cerebral veins, which terminate in the sujjerior sagittal sinus, and the lower portions become the inferior cerebral veins. These open into the primitive anterior cerebral vein which lies in the lateral fissure of the hemisj)here and becomes the medial cerebral vein of the adult. Very commonly one of the intercommunicating tributaries persists in the whole of its length and so becomes the great anastomotic vein (Trolard). The dorsal longitudinal anastomosis extends caudally on each side, beyond the fusion by which the median unpaired sagittal sinus is formed, and connects the sagittal sinus with the tributaries of the primitive middle and the posterior cere- bral veins. This jtortion of the anastomosis becomes displaced caudally and laterally by the extending cerebral hemispheres, and it becomes converted, on each side, into the horizontal part of the transverse sinus, the sigmoid part of the transverse sinus being formed from the primitive posterior cerebral vein. At the same time the primitive middle cerebral vein becomes the superior petrosal sinus; and the inferior petrosal sinus is formed as a new structure which lies in the position of the original vena capitis medialis, but does not appear to be formed from it. The extra-cranial parts of the anterior cardinal veins become connected together, in the upper or cephalic part of the thoracic region, by a transverse anastomosis which becomes the greater part of the left innomin- ate vein. A short distance cephalwards of this transverse connexion, the primitive vein of the upper limb ultimately opens into the anterior cardinal vein. The portion of the anterior cardinal vein of the right side, which lies between the entrance of the limb vein and the transverse anastomosis, becomes the right innominate vein (Fig. 839), Ophthalmic vein P
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1914
