358 LABORATORY MANUAL OF HUMAN ANATOMY 



(a) Decussation of brachium conjunctivum (decussatio 



brachii conjunctivi). 



(b) Dorsal decussation of tegmentum (decussatio teg- 



menti dorsalis) (German 0. T. fontaineartige 

 Haubenkreuzung) . 



(c) Ventral decussation of tegmentum (decussatio teg- 



menti ventralis). 



(9) Lateral fillet (lemniscus later alls}. 

 (10) Medial fillet (lemniscus medialis). 



(B) Base of peduncle (basis pedunculi) (0. T. "foot" of cerebral 

 peduncle, or pes pedunculi). 



(1) Pyramidal path (fasciculi cerebrospinales) . 



(2) Temporal pontile path (fasciculus temporopontilis) (0. T. 



Turk's bundle). 



(3) Frontal pontile path (fasciculus frontopontilis) (0. T. Ar- 



nold's bundle). 



Between (A) and (B), study the substantia nigra (substantia 

 nigra) (" black substance"). 



In the corpora quadrigemina. 



(1) Zonal layer (stratum zonale). 



(2) Gray layer of superior colliculus (stratum griseum colliculi supe- 



rioris). 



(3) Nucleus of inferior colliculus (nucleus colliculi inferioris). 



(4) Deep white layer (stratum album profundum). 



Sections through Prosencephalon (Sectiones diencephali et telen- 

 cephali). 



Take the portion still remaining of the right cerebral hemi- 

 sphere; with a broad, thin, sharp brain-knife, make horizontal 

 slices, one-half or one centimetre thick, down as far as the level 

 of the commissura anterior cerebri. Make a drawing of the 

 surface of each slice. (Vide Fig. 177.) 



The left half of the brain, thus far preserved intact, should 

 now be divided, at the choice of the instructor, either into vertical 

 frontal or into obliquely frontal sections, the latter according to 

 the method of Pitres. 1 All the oblique sections pass in planes 

 parallel to the course of the sulcus centralis Rolandi. Place 

 the four fingers of the left hand in the sulcus centralis [Eolandi] , 

 the hemisphere lying upon its medial surface with the polus 

 occipitalis directed towards you. With the sharp, broad, thin 

 brain-knife, make six sections from before backward, as indi- 

 cated in the accompanying diagram. (Cf. Fig. 170.) 



1 Pitres, Recherches sur les lesions du centre oval des hemispheres cerebraux, 

 etudiees au point de vue des localisations cerebrales. Paris, 1877. 



