THE NERVOUS SYSTEM 



THE SPINAL PATH FOR PAIN AND TEMPERATURE SENSATIONS 



Pain and temperature sensations are mediated by closely associated though 

 not identical paths, and it is convenient to consider them at the same time. 



Neuron I. The first neuron of this system has its cell of origin located in 

 the spinal ganglion. Its axon divides into a peripheral branch, directed through 



Internal capsule 



Thalamus 



X Mesencephalon 



Medulla oblongata 



- Lateral spinothalamic tract 

 Spinal card 



Dorsal root and spinal ganglion 

 Fig. 231. Diagram of the path for pain and temperature sensations. 



the peripheral nerve to the skin, or in the case of the pain fibers also to the deeper 

 tissues, and a central branch, which enters the spinal cord through the dorsal 

 root and almost at once terminates in the gray matter of the posterior gray column 

 (Fig. 231). As was shown in Chapter VII, there is reason to believe that the 



