950 



THE NERVE SYSTEM 



band of white fibres which, as seen on horizontal section, appears bent, very much 

 as a leg is bent on the thigh, with the knee (genu) directed mesad. The frontal 

 or caudatolenticular division or limb is confined between the opposed faces of 

 the caudate nucleus and lenticular nucleus. The genu receives the mesal apex 

 of the lenticular nucleus in its hollow, while the caudal or thalamolenticular 

 limb lies between the opposed faces of lenticular nucleus and thalamus. The 

 frontal limb constitutes about one-third, the caudal limb two-thirds of the internal 

 capsule mass. 



NT. CORNU OF 



LAT. VENTR. 



CAVUM SEPTI 



PELLUCID! 



CORTEX OF ISLAND 



OF REIL 



FOR NIX 



EXTERNAL CAPSULE- 

 ALBICANTIO- 



THALAMIC TR. 



PARACLAUSTRAL 

 WHITE LAMINA 



EPIPHYSIS 



TAIL OF CAUDATE 



NUCLEUS 



HIPPOCAMPUS 



CHOROID PLEXUS 



OPTIC RADIATION 



CALCARINE 

 FISSURE 



WHITE STRIPE OF 

 VICQ D'AZYR 



FIG. 704. Horizontal section through the cerebrum. The various structures are shown in their natural 

 appearance on the right side and are named on the left side. 



The term "internal capsule" is often loosely employed and is variously stated 

 to include fibre tracts which do not course between the cerebral cortex and the 

 "lower" brain centres. In a strict sense it is a mass of fibres which converge, 

 like the sticks of a fan, toward the cerebral base and into the crusta. Dorsad 

 of the basal ganglia the fibres radiate in various directions, streaming among the 

 radiating callosal fibres and forming the so-called corona radiata. Yet other 

 fibre tracts leave and enter the great ganglia at various altitudes along the internal 

 capsule, and we must therefore distinguish the following cerebral fibre systems. 



Projecting systems, ascending and descending (in the functional sense), of 

 longer and shorter course, connecting the cerebral cortex with (o) spinal gray 

 centres; (6) mid-brain and pontile nuclei; (c) basal ganglia and thalamus. The 



