326 LABORATORY MANUAL OF HUMAN ANATOMY 



The student may now remove one cerebral hemisphere (hemi- 

 sphaerium cerebri). With a very sharp, thin knife, cut through 

 the right cerebral peduncle just behind the right corpus mam- 

 millare. Turn the brain over ; press the two hemispheres apart 

 by widening the longitudinal fissure of the cerebrum; expose 

 the corpus callosum and cut through it and the tissues beneath, 

 as near the middle line as possible, or a very little to the left of 

 it, so as to leave the septum pellucidum on the right hemisphere. 

 Carry the incision backward to meet the transverse incision 

 already made through the cerebral peduncle. This right hemi- 

 sphere may be kept in the preserving fluid while the rest of the 

 brain is being studied. 



External Morphology of Rhomboid Brain and Midbrain 

 (Rhombencephalon and Mesencephalon). 



Lift the cerebellum gently from behind and observe the rela- 

 tion of its inferior surface to the medulla oblongata and ven- 

 triculus quartus. With a sharp, thin brain-knife, cut through 

 the cerebellum in the middle line of the worm (vermis). Do no 

 injury to the floor of the fourth ventricle, but permit the incision 

 to pass forward through the anterior medullary velum as far 

 as the inferior colliculi of the midbrain. Cut through the three 

 cerebellar peduncles on the right side, the superior peduncle 

 (brachium conjunctivum) , the middle peduncle (brachium pon- 

 tis), and the inferior peduncle (corpus restiforme). Eemove 

 the right half of the cerebellum and preserve it for further study. 



Make three drawings showing anterior, lateral, and poste- 

 rior views of rhombencephalon, and illustrating the following 

 structures : 



Medulla Oblongata. 



(a) Anterior median fissure (fissura mediana anterior}. 



(b) Posterior median fissure (fissura mediana posterior). 



(c) Blind foramen (foramen caecum). 



(d) Pyramid (pyramis [medullae oblongatae] ). 



(e) Decussation of pyramids (decussatio pyramidum). 



(f) Anterior lateral sulcus (sulcus lateralis anterior}. 



(g) Posterior lateral sulcus (sulcus lateralis posterior), 

 (h) Olive (oliva) (0. T. olivary eminence). 



(i) Restiform body (corpus restiforme) (0. T. inferior cerebellar 



peduncle). 



(j) Lateral funiculus (funiculus lateralis). 

 (k) Cuneate funiculus (funiculus cuneatus) (0. T. column of Bur- 



dach). 



