

Corpus Striatum 53 



the uncinate gyrus. Close above it is the convolution which lies along 

 the margin of the longitudinal fissure the marginal convolution. It 

 begins at the anterior perforated space, and ends just in front of the 

 quadrate lobe. Between the gyrus fornicatus, or callosal convolution, 

 and the marginal convolution, is the calloso-marginal fissure. 



The para-central lobe is chiefly formed by the top of the ascending 

 frontal convolution, which looks into the marginal convolution. 



The quadrate lobe is the mesial surface of the parietal lobe ; just 

 behind it is the cuneate lobe of the occipital. 



Jacksonian epilepsy is the convulsive attack, followed by tem- 

 porary paralysis, of a group of muscles, which results from irritation of 

 some part of the motor area. Chronic inflammation of the brain or 

 its membranes is a common cause of it, the inflammation being very 

 often the result of syphilis. Perhaps at first only one group of 

 muscles is affected, but as the irritation extends the neighbouring 

 parts of the cortex are implicated, and the convulsions become more 

 widely distributed. From what has gone before (p. 52) it is evident 

 that if the epilepsy begin as a facial spasm the muscles of hand and 

 arm will be next involved, and lastly those of the leg. When the last 

 group of muscles is first attacked those of the arm are likely to 

 follow suit, and ultimately those of the face. If the disturbance begin 

 in the arm-centres the muscles both of leg and of face are likely to 

 be involved subsequently. 



The fibres from the motor area subsequently pass through the 

 corpus striatum and the internal capsule ; haemorrhage, therefore, in 

 either of these latter situations may cause extensive paralysis upon the 

 opposite side of the body. Indeed, the corpus striatum has been 

 called, on account of its associations, ' the motor ganglion,' the optic 

 thalamus, on the other hand, being ' the sensory ganglion.' 



The sensory region of the cortex is posterior to the motor, and 

 in the case of a destructive lesion of the motor area, if there be 

 hemi-anaesthesia as well, it is certain that the injury is widespread, and 

 the chance of relief by trephining remote. 



THE BASAL GANGLIA 



The corpus striatum is a grey ganglion which is streaked, or 

 striated, by white fibres on their way down to the antero-lateral column 

 of the cord, through the superficial, or motor, part of the cms the 

 crusta. These fibres reach the cortex through the fan-like corona 

 radiata. The presence of the vesicular tissue in the ganglion detracts 

 from its strength, and, being freely supplied with branches of the 

 middle cerebral, which enter it through the anterior perforated space, 

 it is often the seat of haemorrhage. Motor paralysis of the opposite 

 side results, just as if the lesion were in the motor area or in the crus. 



Cerebral haemorrhage is generally the result of kidney-disease, as 



