STRUCTURE OF THE CRUS CEREBRI. 743 



peduncle of the cerebellum), in connection with which a roundish 

 mass of grey substance named the nucleus of the tegmentum or red Red 

 nucleus (fig. 283. p. 775) may be seen on transverse section of the fore nueleus - 

 part. Above, the tegmentum joins the under surface of the optic 

 thalamus. 



Between the tegmentum and the substantia nigra will be seen, on Stratum 

 section, an intermediate greyish layer known as the stratum medium. 

 interim-dill., and above this, and along the outer margin of the 

 tegmentum in the region of the inferior quadrigeminal body, will be 

 seen a whitish band, the fillet (tig. 269). 



The POSTERIOR PERFORATED SPACE (fig. 268, </) is situate in the Posterior 



depression between the crura cerebri. The bottom of this hollow is JJotf**^ 

 formed by a layer of grey matter, which is perforated by the central 

 branches of the posterior cerebral arteries. This structure forms the 

 hinder part of the floor of the third ventricle. 



The CORPORA ALBICANTIA (corp. mamillaria ; ) are two round Corpora 

 white bodies, about the size of small peas, which are constructed in al 



inf. quad, body aqueduct of Syluiua 



_ Mmm]r lamina tjuadrigcmina 



tjrcij matter of 

 a sue duct . 



f il ^r( ^O^ \\fcffmintum 

 sup.ped. of 

 cerebellum 



crusta 



FIG. 269. TRANSVERSE SECTION OF THE CRURI CEREBRI THROUGH THE 

 SUPERIOR CORPUS QUADRIGEMINUM. 



greater part by the crura of the fornix. If one, say the right, is 

 cut across, it will be seen to contain grey matter. 



The TUBER CINEREUM (h) is a portion of the thin grey layer forming Tuber 

 the floor of the third ventricle, which is continuous behind with the cmereum 

 grey matter of the posterior perforated space, and in front, above 

 the optic commissure, with the lamina cinerea. It is convex on the 

 surface, and is prolonged at its fore part into the following body. 



The INFUXDIBULUM is a funnel-shaped tube which reaches from and in- 

 the tuber cinereum to the posterior lobe of the pituitary body. It fundibulum - 

 consists of a layer of grey matter ; and its cavity is a part of the 

 third ventricle. In the foetus this tube is open between the third 

 ventricle and the pituitary body, but in the adult it is closed below. 



The PITUITARY BODY will be very imperfectly seen when it has Pituitary 

 been dislodged from its resting place : it should therefore be 

 examined when opportunity otters in the base of the skull by 

 removing the surrounding bone. 



It is situate in the hollow of the sella Turcica on the sphenoid situation ; 

 bone, and consists of two lobes, anterior and posterior. The anterior two lobes. 

 is the larger, and is hollowed out behind, where it receives the round 

 posterior lobe. In the adult this body is solid and firm in texture ; 



