THE NERVOUS SYSTEM 



Centrally, the olfactory nerves are connected through the 

 olfactory bulb and tract with the fornix and the uncus. Exist- 

 ing knowledge is by no means definite with regard to these 

 connexions and the symptom of anosmia is of little value, 

 therefore, for topical diagnosis. 



The Second or Optic Nerve arises in the cells of the 

 retina and, passing backwards and medially (p. 16), leaves the 



--Optic nerve 



ucleus 



Lateral geniculate body 

 'Pulvinar 



, ^Superior corpus quadri- 

 geminum 



Occipital cortex 



FIG. 28. Diagram of course of Visual and Pupillary Fibres. 



orbit through the optic foramen to reach the optic chiasma 

 (Fig. 8). Lesions of the optic nerve will, according to their 

 degree of severity, cause partial or complete blindness in the 

 eye of the same side. 



The fibres which arise from the nasal side of the retina 

 decussate at the optic chiasma and then pass backwards along 

 the optic tract of the opposite side. The fibres from the 

 temporal side of the retina do not decussate, but enter the 



