56 



LABORATORY OUTLINE OF NEUROLOGY 



ward into the cerebellum (recessus cerebelli) and that it is only 

 in this region that the cerebellum forms the true roof of the 

 ventricle. Note that the roof of the third ventricle is also a 

 choroid plexus extending from the pineal body to the interven- 

 tricular foramen and that a deep fissure, which is outside the 

 brain, extends forward from the region of the tentorium cere- 

 belli between this plexus and the overlying body of the fornix. 

 In the sheep the medial surface of the hippocampus is visible 

 within this fissure (marked "gyrus dentatus" in Fig. 10) . Locate 



/Atrpedtr 

 •^J.cgeamed 



Fig. 12. — The lateral surface of the medulla oblongata and midbrain of 

 the sheep. Xlf. br.c.i., brachium of colliculus inferior; br.p., brachium 

 pontis; c.gen.med., corpus geniculatum mediale; coch., nucleus cochlearis; 

 col.inf., colliculus inferior; col.sup., colliculus superior; c.r., corpus resti- 

 forme; f.cun., fasciculus cuneatus; f.lat., fasciculus lateralis; III to XII, 

 cranial nerves; lem.l., lemniscus lateralis; n.v., nucleus vestibularis; ped. 

 cer., pedunculus cerebri; pyr., pyramid; trap., corpus trapezoideum; tr. 

 ped.tr., tractus peduncularis transversus; tr.sp.cb.d., tractus spino-cerebel- 

 laris dorsalis; tr.sp.V ., tractus spinalis trigemini; tub.cun., tuberculum 

 cuneatum; V.m., motor root of trigeminus; V.s., sensory root of trigeminus. 



the attachment of the choroid plexus of the third ventricle along 

 the tcenia ventriculi tertia, or taenia thai ami, and note also that 

 the plexus itself is continued through the interventricular for- 

 amen into continuity with the lateral choroid plexus within the 

 ventricle of the cerebral hemisphere. In a specimen from which 

 the septum pellucidum has been torn away this continuity can 

 be readily observed; but do not at this time attempt further 

 dissection of the lateral choroid plexus (see Section 132) . 

 The choroid plexuses of the third and fourth ventricles are 



