FIBRES OF THE INTERNAL CAPSULE OF THE BONNET MONKEY. 
55 
degeneration affected the internal three-fonrths of the lower level, and only the 
posterior fourth escaped. In this case all the frontal lobe, the whole of the parietal 
lobe and a great part of the occipito-sphenoidal lobe had been destroyed by an 
extensive superficial softening. 
Meynert'"'* * * § divides the internal capsule into live different kinds of bundles, 
viz. :— 
1. Fibres passing from the cortex, as laminae medullares, between the zones of the 
lenticular nucleus. 
2. A bundle passing from the frontal region to the optic thalamus, and also forming 
part of the stratum zonale. 
3. Fibres from the nucleus caudatus to the crus cerebri. 
4. Fibres from the nucleus lenticularis to crus cerebri. 
5. A group of fibres (the most posterior) which pass to the tegmentum. 
Hughes Bennett! and Campbell published a remarkable case in which the left 
arm was completely paralysed by a haemorrhage in the internal capsule. 
The lesion was found post-mortem and located as nearly as possilfie to the junction 
of the most anterior and second fourth of the posterior limb. 
Dejerine;}; reported a case in which a tubercular tumour of the size of a nut, 
“ seated on the internal capsule, between the posterior part of the optic thalamus 
and the capsule itself,” produced paralysis of the right upper limb, together with 
incomplete right hemianmsthesia. 
Obersteiner§ figures an arrangement of the fibres of the capsule and crus similar 
to that given by Brissaud and Charcot. 
Wernicke II states that the anterior limb of the internal capsule is composed of 
fibres, which pass partly into the subthalamic region, and partly into the mesial side 
of the crus, and that the fibres coming from the nucleus caudatus pass circuitously 
throuorh the laminae medullares round the two inner zones of the lenticular nucleus. 
Anatomy of the Internal Capsule. 
Definition of the term .—As before said the term internal, capsule has been given to 
the descending and ascending fibres of tlie corona radiata, while passing between the 
basal ganglia ; consequently we assume that the term is only applicable to the fibres 
so loirg as they are passing between the two following levels. 
The upper of these levels is shown in Plate IT fig. 2, which is constructed from 
* ‘ Psychiatrie,’ Wien, 1884, p. 77. 
t “ Case of Brachial Monoplegia due to Lesion of the Internal Capsule,’' ' Bi-aiu,’ vol. 8, p. 78, Aju-il, 
1885. 
t Quoted in article “ Encephale,” ‘ Dictionnaire des Sciences Medicales,’ 1887. 
§ ‘ Anleitung beim Studium des Baues der Nervosen Centralorgane im gesunden und krauken 
Zustande,’ 1888, p. 255. 
II ‘ Lehrbuch A'on den Gehirnkranheiten,’ Cassel, 1881, vol. 1, p. 85, tig. 44. 
