54 
DK. C. E. BEEVOR AND MR. V. HORSLEY ON THE EXCITABLE 
believing- that in a horizontal section through the upper border of the middle zone of 
the lenticular nucleus, the pyramidal tract, including the tibres to the seventh and 
twelfth nerves, occupies the second, third, and fourth sixths of the posterior limb of 
the internal capsule. 
Charco^'" sub-divided the capsule according to his well-known plan, as follows :— 
The anterior limb he termed the lenticulo-striate bundle. The posterior limb he 
subdivided into thirds, the two anterior of which he regarded as belonging to the 
pyramidal tract, while the remaining third was, he believed, limited to the trans¬ 
mission of afferent impressions. 
We may remark that, as will subsequently be seen, this description applies only to 
one sectional level of the capsule. 
BRiSSAUDt made the most numerous clinical observations on this point. According 
to him there exist in the crus cerebri four bundles, whose relations from behind for¬ 
wards may be stated as follows :— 
1. A posterior bundle for tbe transmission of sensory impressions (Charcot, 
Meynert). 
2. A middle bundle for tbe innervation of the muscles of the limbs and trunk. 
3. A bundle of small size, which he called the geniculate bundle on account of its 
connection with the genu of the internal capsule. This bundle includes motor fibres, 
and is distributed to the bulbar nuclei for the movements of the muscles of the face, 
the tongue (perhaps the soft palate) ; in fact to all parts of the head and face which 
can be acted on voluntarily. 
4. An internal bundle which ends in like manner in the bulb, and whose degenera¬ 
tion only seems to be coincident with intellectual derangements. 
To these four bundles tbe four following divisions of the internal capsule 
correspond. 
1. To the posterior bundle, the posterior third of the hinder limb corresponds (he., 
the region of hemiansesthesia, Charcot, Raymond). 
2. To the middle bundle, the anterior two-thirds of the hinder limb. 
3. The bundle which he called geniculate, corresponds to the genu of the capsule. 
4. Finally the whole of the anterior limb of the internal capsule corresponds to the 
internal bundle of the crus. 
Contrary to what certain authors have stated, the crus cerebri cannot become com¬ 
pletely degenerated ; in other wmrds there is a limit wdrich the degeneration cannot 
overstep. 
This maximum degeneration is recorded by him in observation VII., where the 
* ‘ Le 90 iis sur les Localisations dans les Maladies dn Cerveau et de la Moelle EpiniM-e,’ 1876-1880, 
pp. 221-224. 
I ‘ RecLerclies sur la Contracture Permanente des Hemiplegiques,’ Paris, 1880, p. 38. 
