156 CEREBRAL LOCALIZATION 



otitis media may be suffering from labyrinthitis or 

 from cerebellar abscess. If injection causes no 

 nystagmus, the labyrinth is destroyed. 



TUMOURS IN THE CEREBELLO-PONTINE 

 ANGLE. 



This is a very common location for cerebellar 

 tumours, and a comparatively favourable one for 

 surgery, seeing that in many instances the growth 

 is simple, and can be enucleated without recurrence. 

 Allen Starr finds in the literature sixty-nine cases 

 cured by removal. In many of these there was 

 restoration to good, in some to perfect, health. 

 Diagnosis, therefore, becomes peculiarly important. 



In addition to the signs mentioned above, certain 

 nerve-root symptoms may develop, and the pons may 

 be pressed on. Mental trouble is quite unusual. 



We may classify the evidence as follows : 



1. General : headache, vomiting, optic neuritis, 

 slow pulse, blue-blindness, perhaps convulsions. 



2. Cerebellar signs : staggering, vertigo, ataxia, 

 weakness, tremor, and perhaps absent knee-jerk ; 

 these may be unilateral, on the same side as the 

 growth. Nystagmus. 



3. Nerve-root symptoms affecting the same side : 

 pressure on the fifth, with corneal anaesthesia and 

 loss of reflex, and weakness of jaw muscles ; pressure 

 on the sixth, with internal strabismus; pressure on 

 the seventh, with facial weakness ; pressure on the 

 eighth, with tinnitus, loss of perception for upper 

 notes (tested by Galton's whistle), or absolute deaf- 

 ness ; pressure on the ninth, tenth, and eleventh, 



