810 



PHYSIOLOGY. 



ocular sphere an up-and-down movement. The superior or inferior 

 oblique muscle, acting alone, gives the eye an oblique movement. 



Paralysis of right 

 external rectus. 



Paralysis of right 

 internal rectus. 



Paralysis of right 

 superior rectus. 



Paralysis of right 

 inferior rectus. 



Paralysis of right 

 superior oblique. 



Paralysis of right 

 inferior oblique. 



Fig. 361. 



-Positions of Images in Ocular Paralyses. 

 The true image is black, the false is red. 



(BALK) 



Coordinated Movements. The two eyes always present coordi- 

 nated movements in order to maintain the parallelism or conver- 

 gence of the two visual lines. The visual line is that line which 

 passes between the object, center of the pupil, and center of rota- 

 tion of the ocular globe. For accommodation at a distance the two 

 visual lines are parallel. In accommodation for near objects the 

 lines are convergent. 



Fig. 362. Capsule of Tenon. (BALL, after MERKEL.) 



So long as the muscles of the eyeball are normal in function 

 their movements are in cooordination. Should one or more become 

 paralyzed or seized with spasm, then proper parallelism and conver- 



