B EM OVAL OF THE BRAIN. 431 



§ 1109. Other Methods of Removing the Brain. — The following methods are sim- 

 pler and more expeditious than the preceding, but less satisfactory in some respects. 



(A) By Nipping away the Calva (Vault of the Cranium). — This metliod is especially 

 adapted for the rapid exposure of the dorsal and lateral aspects of the hemispheres or the 

 cerebellum. When, for example, the brain of a recent or alcoholic specimen of some rare 

 animal is believed to be so soft that extraction by the usual method is not feasible, a 

 drawing or photograph can be taken so as to represent at least the form, and the arrange- 

 ment of the fissures. 



Instruments and Materials. — These are the same as for the 

 method abeady described (§ 1099). 



Decapitation. — This is to be performed as directed in § 1101, aud 

 the eyes, zygomata aud temporal muscles removed. 



§ 1110. — Exposure.— W\i\\. the large or medium nippers cau- 

 tiously penetrate the dorso-lateral aspect of the cranium, but with- 

 out piercing the dura. Pass the tracer between tiie bone and the 

 dura at all sides, keeping tlie point away from the brain ; then 

 remove so much of the bone as is separated. When the orifice is 

 sufficiently enlarged, employ the probe or the handle of a scalpel 

 in place of the tracer. If the adliesions along the meson are very 

 firm, remove the bone on both sides, and divide them with the 

 arthrotome or scalpel. 



In exposing the cephalic part of the hemispheres, the large 

 frontal sinuses (Fig. 56, 59, 60, § 524) will be opened ; note the 

 density of the ectal layer {tabula externa) of the cranium, and the 

 elliptical orifices of the infundibula. 



If the hemispheres only are to be exposed, or if it is desirable to 

 preserve the facial region, the dura may be divided with the scis- 

 sors along the margins of the bone, and the falx (Fig. 88) carefully 

 cut near the cephalic and caudal ends of the hemispheres, so as to 

 permit the removal of the dorsal dura. The lateral aspects of the 

 hemispheres may be exposed so far as desired, the olfactory crura 

 (PI. I, Fig. 2) may be divided, and the JiemispJieres together with 

 the parts covered by them removed by holding the head so that its 

 frontal region tends to fall out, and successively dividing the iViV. 

 optici^ the infundibulum and the other nerves as they appear at 

 the base of the brain, and lastly the crura cerebri. 



% 1111. Commonly, however, the removal of the dura should be 

 postponed, and the olfactory lobes should be carefully exposed by 

 the removal of the thin bones which surround them ; this is of 

 course facilitated by removing the entire maxillary region as directed 

 in § 1102. 



