EFFERENT PATHS AND REFLEX ARCS 



319 



The motor path for the spinal nerves includes the corticospinal tract and the 

 spinal primary motor neurons. 



Neuron I, or upper motor neuron. The giant pyramidal cells of the motor 

 cortex give rise to the fibers of the corticospinal tract which is also known as 



Fissura longitudinalis cerebri 

 Radiatio corporis callosi,. 



Septum pellucidum x 



Plexus chorio- 



ideus ventricul 



lateralis 



Corona radiata,. 



Columna, 

 fornicis 

 'Plexus chorio- 

 ideus ventriculi ~"~V 



tertii 

 Capsula interna 



Thalamus 



Ventriculus - 



tertius 



Fossa inter- 

 peduncularis 



(Tarini) 



Cornu inferius 

 ventriculi 

 lateralis 



Peduncuh 

 cerebri 



Brachium pontj 



Fasciculi longit 

 nales(pyramida 

 pontis 



Facies inferio 



, Gyrus frontalis superior 



f Truncus corporis callosi 



( Cornu anterius ventriculi 

 lateralis 

 Caput nuclei caudati 



Nn.facialisund 

 acusticus 



Flocculus 

 glossopharyngctis 



N. vagus 

 Nucleus olivaris inferior 



Fibrae pontis super 



Pyramis medullae oblongatae / ^ Decussatio pyramidum 



Fig. 238. Section through the brain in the axis of the brain stem, showing the entire extent of 



the corticospinal tract. (Toldt.) 



the cerebrospinal fasciculus or pyramidal tract. These fibers traverse the rostral 

 half of the posterior limb of the internal capsule, the intermediate three-fifths 

 of the basis pedunculi, the basilar portion of the pons, and the pyramid of the 

 medulla oblongata, and after undergoing a partial decussation are continued into 

 the spinal cord (Figs. 237, 238). At the pyramidal decussation in the caudal 



