ME TEXCEPHA L ON 



"21 



extra ventricular portion certain fissures, and the elevated portions which these fis- 

 sures map out, require notice. 



Fissures. — Commencing in front, we find the anterior fissure (fissura longi- 

 tudinalis anterior) occupying the middle line. It is shallow below, where it is 

 almost separated from the anterior longitudinal fissure of the cord by the decussa- 

 tion of the pyramids; deeper above, where it separates the pyramids of opposite 

 sides. Superiorly, it ends in a })lind recess, under the margin of the pons, the 

 foramen caecum posterius, or foramen caecum of Vicq d'Azyr. External to 

 the anterior fissure, Ave find the sulcus lateralis ventralis ; the latter intervenes 

 between the pyramid and the olive above, and extends downwards immediately in 



Fig. 428. — Metexcephalon, Mesencephalon, and Thalamencephalox, from the Doesai. 



Surface. (After Obersteiner. ) 



ANTERIOR CORNU 



OF LATERAL 



VENTRICLE 



FIFTH VENTRICLE 



SEPTUM L VCID UM 



ANTERIOR PII^ 



LA RS OF FORNIX 



TAENIA SEMI- 



CIRCULARIS 



ANTERIOR 



COMMISSURE 



THIRD VENTRICLE 



MIDDLE 

 COMMISSURE 



SULCUS 

 CHOROIDEUS 



NA TES 



CORPUS GENICU- 

 LA TUM INTERNUM 



LA TERA L OROO VE 



OF 

 MESENCEPHA LON 

 PONS 



CONDUCTOR 

 SO NOR US 

 SULCUS LONGITUDINALIS 

 MEDIAN US 



TRIGONUM HYPOGLOSSI 

 CORPUS RESTIFORME 



CLA VA 

 POSTERIOR FISSURE 



SULCUS PA RAMEDIANUS 

 DORSALIS 



SULCUS LA TERA LIS DORSALIS 



\xUJ^ 



CORPUS CALLOSUM 



CA UDA TE 

 NUCLEUS 



FORAMEN OF 

 MONRO 



OPTIC THALAMUS 



STRIA PINE A LIS 



PEDUNCULUS 

 CONARII 



PINEAL BODY 



SULCUS CORP. 

 QUAD. LONGI- 

 TUDINALIS 



TESTIS 



FRENUL UM VELI 

 LING ULA 



EMINENTIA TERES 



TUBERCULUM 

 ACUSTICUM 



ALA CINEREA 



TUBERCULUM CUNEA TUM 

 FUNICULUS GRACILIS 

 FUNICULUS CUNEA TUS 

 LA TERA L COL UMN 



front of the olive and the lateral cohunn. It is joined below the olive by the post- 

 olivary sulcus. FroTu its upper part, a fissure (sulcus parapyramidalis) passes 

 downwiirds and inwards to join the anterior fissure. 



On the posterior surface of the medulla we find the posterior fissure (fissura 

 longitudinalis posterior) occupying the middle line. It is continuous below with 

 the posterior fissure of the spinal cord, and ends above at the fourth ventricle. 

 External to this we find the sulcus paramedianus dorsalis, and more externally 

 the sulcus lateralis dorsalis. The former of these two fissures ends above at the 

 apex of the clava, the latter extends for some distance further upwards. To reca- 

 pitulate, the fissures of the medulla, taken in order from before backwards, are as 

 46 



