THE BRAIN. 



511 



Head, neck, and face: Lower two-thirds* of the ascending 

 frontal and the bases of the lower and middle transverse frontal 

 convolutions. 



Upper limb: Upper third of the ascending frontal, base of 

 upper transverse frontal, ascending parietal, and part of the mar- 

 ginal convolutions. 



Lower limb : Parietal lobule and posterior part of marginal. 



Trunk : Marginal convolution between the leg and arm. 



It is to be understood that the action is in all cases crossed 

 that is, excitation of one side of the cerebrum causes the move- 

 ments spoken of to occur on the opposite side of the body, and 

 the same is true of the paralysis which follows disease or injury. 



As a result of destruction of the Rolandic area degeneration 



B 



C 



MID BRAIN 



FIG. 302. Degeneration after destruction of the Rolandic area of the right hemi- 

 sphere (after Gowers). 



occurs, and its course is well shown in the illustration (Fig. 302), 

 in which the shaded portions represent the parts that have under- 

 gone degeneration. 



Speech-center. Articulate speech requires the exercise of 

 memory and the power of producing certain voluntary move- 

 ments. Inability to produce articulate speech is known as aphasia. 

 If the memory of words is absent while the power to produce 

 the movements remains, it is amnesic aphasia, and if the reverse 

 condition exists, it is ataxic aphasia. It 'is believed that the 

 center which presides over language is in the frontal lobe on 

 the left side, and has received from its discoverer the name of 

 Broca's convolution. Some localize it in the third frontal convo- 

 lution ; others regard it as being more diffused, and locate the 

 center in the convolutions surrounding the lower end of the fissure 



