DISSECTION OF THE HEAD AND NECK 



341 



(a) 



(6) 

 (c) 



(d) 



(e) 



(9) 

 (h) 



(*) 



Caudate nucleus (nucleus caudatus). 



Terminal stria (stria terminalis) (0. T. taenia semicireularis). 



Terminal vein (vena terminalis) (0. T. vein of the corpus striatum). 



Lamina affixa (lamina affixa) ("fastened layer"). 



(The embryology of the part must be studied, in order to under- 

 stand the origin of this structure.) 



Chorioid plexus of lateral ventricle (plexus chorioideus ventriculi lat- 

 eralis ) . 



Epithelial chorioid layer (lamina chorioidea epithelialis). 



Chorioid taenia (taenia chorioidea). 



Thalamus (thalamus) (showing through). 



Taenia of fornix (taenia fornicis) (0. T. sharp edge of fornix). 



FIG. 154. 



Transverse section through the tela chorioidea, ventriculi tertii, and adjacent parts. 

 II, lateral ventricle ; III, third ventricle ; Cc, corpus callosum ; F, fornix ; Th, thalamus ; St. TO, 

 stria medullaris ; St. t, stria terminalis ; V. t, vena terminalis ; L, lamina affixa ; 1, taenia thalami ; 2 , 

 taenia chorioidea ; 3, taenia fornicis. The figure shows the continuity of the taeniae and the epithelial 

 layer of the plexus chorioidea. (After His, Die Anat. Nomenclatur, Leipzig, 1895, p. 166, Fig. 21.) 



In the posterior horn of the ventricle study 



(a) Roof and lateral wall formed by tapetum. 



(b) Two ridges on medial wall. 



(ba) Upper ridge = bulb of posterior horn (bulbus cornu poste- 

 rioris), due to pars occipitalis of radiatio corporis callosi, 

 the so-called " forceps major/' hooking around the fissura 

 parieto-occipitalis. 



(feb) Lower ridge = calcar avis (calcar avis) (" cock's spur") (0. 

 T. hippocampus minor), due to fissura calcarina. 



Before studying the inferior horn of the ventricle in detail, 

 insert the fingers cautiously beneath the pars frontalis and pars 

 parietalis of the operculum of the island, and tear away the 

 cortex. This exposes the island thoroughly, and its relations to 

 the lateral ventricle can be examined. 



In the inferior horn of the ventricle study 



(a) Its narrow inferior wall. 



(aa) Collateral eminence (eminentia collateralis) , corresponding 

 to the fissura collateralis ; it is sometimes absent. 



