DISSECTION OF THE HEAD AND NECK 



347 



(d) Hypothalamic sulcus of Monro (sulcus hypothalamicus [Monroi]). 



Note the importance of this in connection with the embryology of 

 the brain. Compare with the sulcus limitans in the floor of the 

 fourth ventricle. 



(e) Intermediate mass (massa intermedia) (0. T. middle or soft or gray 



commissure). 

 (/) Optic recess (recessus opticus). (Cf. W. His's models of developing 



brain.) 



(g) Recess of infundibulum (recessus infundibuli) . 

 (h) Anterior commissure of cerebrum (commissura anterior [cerebri]). 

 (i) Triangular recess (recessus triangularis) . 



SECTIONS THROUGH BRAIN (SECTIONES 

 ENCEPHALI). 



Sections of Medulla Oblongata (Sectiones medullae oblongatae). 



Make three transverse sections through the medulla oblon- 

 gata: (1) at the level of the decussation of the pyramids; (2) 

 between the decussation of the pyramids and the olives; (3) 



FIG. 158. 



Fissura mediana posterior 

 Nucleus fasciculi gracilis 



Nucleus fasciculi cuneati 



Nucleus tract-, 

 spinal is N. tri 

 gemini 



Formatio reticularis- 



Fasciculus gracilis [Golli] 



Fasciculus cuneatus [Burdachi] 



Secondary trigeminal path 



Tractus spinalis 

 N. trigemini 



Fasciculus cere- 

 bellospinalis 



Fila radicularia 

 N. accessorii 



Gowers' tract and the 

 tract to the lateral 



funiculus from 

 Deiters' nucleus and 

 from the red nucleus 



Fasciculus longitudinalis medialis 



Columna anterior 

 Substantia grisea centralis 



Decussatio pyramid um Pyramis [medullae oblongatae] 



Transverse section of the brain-stem of an adult, through the decussation of the pyramids. Magnifica- 

 ation : 6 : 1. (After Spalteholz, Hand Atlas of Hum. Anat., Leipzig, 1903, vol. iii., p. 656, Fig. 725.) 



through the middle of the olives. (Cf. Spalteholz, Fig. 723.) 

 Examine first the unstained cross-sections and subsequently sec- 

 tions, from the same levels, stained by Weigert's method. 1 Use 



1 The study is much simplified if sections through the brain-stem of a new- 

 born babe are used; see Figs. 162-169. 



