. Anatomy, descriptive and applied. Anatomy. PARTS DERIVED FROM THE FORE-BRAIN 907 tion into the third ventricle. The posterior commissure shares rehition with both fore-brain and mid-brain structures and is formed of decussating jfibres which may be enumerated in the following systems: (o) fibres arising in the special nucleus (described on p. 898) for the medial longitudinal bundle; (6) fibres con- necting the two thaland; (c) fibres connecting the habenular nidi; {d) fibres connect- ing the superior quadrigemina. [Note.—The habenular, pineal body, and posterior commissure are generally incl
. Anatomy, descriptive and applied. Anatomy. PARTS DERIVED FROM THE FORE-BRAIN 907 tion into the third ventricle. The posterior commissure shares rehition with both fore-brain and mid-brain structures and is formed of decussating jfibres which may be enumerated in the following systems: (o) fibres arising in the special nucleus (described on p. 898) for the medial longitudinal bundle; (6) fibres con- necting the two thaland; (c) fibres connecting the habenular nidi; {d) fibres connect- ing the superior quadrigemina. [Note.—The habenular, pineal body, and posterior commissure are generally included under the head of epitkalamus.] The posterior perforated substance or postperforatum has be,en described on page 898. It marks the situation of the "interpeduncular ganglion," which is small in man, but very large in rodent brains. From the cells in this primitive gray lamina arise the fibre tracts already described as the taenia pontis (p. 895), and often -vdsible at the point of emergence from the gray substance of the intercrural space. The corpora albicantia (Fig. 673), or corpora mamiUaria, are two symmetrical, I jinirhjmal lininrj of veiHricle V em of corpus / - ^?a.~-i\ -^ striatum Lateral ventricle'''^ \ / // BKSti -run! amuc / Choroid plexus of lateral ventricle. Velum interpositum Veins of Galen Ependymal lining of' ventricle Choroid plexuses of third ventricle Third ventricle Fig. 670.—Coronal section of lateral and third ventricles. (Diagrammatic.) small, round, white protuberances situated side by side in the intercrural space cephalad of the posterior perforated substance, at a point where the floor of the third ventricle rapidly decreases in thickness to form the tuber cinereum. The color of each corpus albicans is white, owing to a superficial stratum of fibres derived from the fornix. Within lie three nuclear masses—two medial, consti- tuting the main mass, and a smaller lateral nucleus applied against the former, so as to represent a cresc
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1913
