CHAPTER XXII 

 THE CEREBRUM AND THE BASAL GANGLIA 



Weights of the encephalon and of certain of its parts The cerebral hemispheres Cerebral 

 convolutions Basal ganglia Corpora striata, optic thalami and internal capsule 

 Tubercula quadrigemina Crura cerebri Pons Varolii Directions of fibres in the cere- 

 brum Fibres connecting the cerebrum with the cerebellum Fibres connecting the two 

 sides of the brain Fibres connecting different cerebral convolutions on the same side 

 (association fibres) Fibres connecting the brain with the spinal cord Cerebral locali- 

 zation Motor cortical zone (Rolandic area) General uses of the cerebrum Extirpa- 

 tion of the cerebrum Comparative development of the cerebrum in the lower animals 

 Development of the cerebrum in different races of men and in different individuals Facial 

 angle Pathological observations Reaction-time Centre for the expressions of ideas 

 in language. 



THE encephalic ganglia are collections of gray matter found in the 

 encephalon, or what is commonly known as the brain. This part of the 

 cerebro-spinal axis is contained in the cranial cavity. It is provided with 

 membranes, which are similar to the membranes of the spinal cord and 

 have been described in connection with the cord and the general arrange- 

 ment of the cerebro-spinal axis. The gross anatomical divisions of the 

 encephalon are the cerebrum, cerebellum, pons Varolii and bulb. As 

 regards their physiological uses, the cerebellum, pons and bulb are to a 

 certain extent subordinate to the cerebrum. In treating of the physi- 

 ology of these parts, it will be convenient to take up first the cerebrum, 

 or the cerebral hemispheres, with their anatomical and physiological 

 connections and their relations to the other parts of the encephalon. 



All parts of the encephalon that act as nerve-centres are more or less 

 intimately connected with each other anatomically, and are finally con- 

 nected, through the bulb, with the spinal cord. The exceptions to this 

 are the centres of olfaction, vision, audition and gustation, which will be 

 considered fully in connection with the physiology of the special senses. 

 The spinal cord, as has been seen, is capable of independent action as a 

 nerve-centre or collection of nerve-centres, also serving as a means of 

 connection between the brain and the parts through the spinal nerves. 

 The motor and sensory cranial nerves are directly connected with the 

 encephalon. 



A detailed anatomical description of the brain would be out of place 

 in this work, as there are many anatomical parts, the exact physiological 



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