DISSECTING MANUAL. 



nective tissue; the anterior is larger and resembles the thy- 

 roid body. [475, 548] 



Lamina Cinerea. This is a thin layer running from the 

 optic chiasm to the rostrum of the corpus callosum. Anterior 

 commissure: This is a round white bundle which connects the 

 olfactory and the temporal lobes; it crosses the midline just 

 in front of the anterior pillars of the fornix, where it is con- 

 nected anteriorly with the lamina cinerea; it projects into 

 the third ventricle, covered by ependyma. [549, 588] 



Third Ventricle. This is a vertical cleft between the thai- 

 ami, extending from the pineal body to the lamina cinerea, 

 and deepest anteriorly. The floor consists, from before back- 

 ward, of the tuber cinereum, corpora mammillaria, locus per- 

 foratus posticus, and, slightly, tegmenta of crura cerebri; the 

 Sylvian aqueduct opens on it below the posterior commissure. 

 The front wall is the lamina cinerea, extending from the optic 

 chiasm to the anterior commissure. The roof is the ependyma 

 stretching between the tsenise thalami; a choroid plexus, 

 from the velum interpositum, invaginates it along each side of 

 the midline, and projects downward. [550] 



The lateral wall is chiefly the mesial surface of the thalamus ; 

 it presents anteriorly a bulging ridge, running downward and 

 backward, produced by the anterior pillar of the fornix. The 

 foramen of Monro leads into the lateral ventricle at the upper 

 and fore part; it is bounded posteriorly by the thalamus 

 (anterior tubercle) and anteriorly by the anterior pillar of the 

 fornix; a groove (sulcus of Monro), a foetal relic, leads from 

 the foramen of Monro to the Sylvian aqueduct. [550] 



The middle commissure crosses the ventricle just in front 

 of its middle. A funnel-shaped diverticulum leads through 

 the tuber cinereum into the infundibulum; another (recessus 

 opticus) runs above the optic chiasm; another (recessus 

 pinealis) runs above the posterior commissure, into the 

 pineal stalk; another (recessus suprapinealis) runs into the 

 ependyma above the preceding. [550] 



[36] 



