342 



ADVANCED PHYSIOLOGY 



face of the eyeball and to the bones on the side of the nose. 

 The superior oblique muscle on the upper surface of the eye 

 passes inward toward the hose, but on reaching it, its tendon 



Super/or 



Inferior 

 Oblique muscle 



Clique muscle 



Optic ,.. 



nerve 



/ 



Infer, ftectus 



FIG. 165. DIAGRAM 



Showing the eyes in position in their sockets, the muscles that move them and 

 the optic nerves. (Fox) 



goes through a loop, which acts as a pulley, and then passing 

 backward is attached near the same place as the rectus muscles. 



DEMONSTRATION. The muscles which move the eye can be well shown 

 by use of the eye of a dog-fish. The skull is cartilaginous and easily cut 

 away, and the muscles are diagrammatically plain. Appendix, Section 30. 



All movements either in a vertical or a horizontal plane 

 must be made by the rectus muscles, and movements not ex- 

 actly in either of these planes may be produced by the com- 

 bined action of two or more of them. It would seem that 

 their contraction would produce all movements the eyes ever 

 make. As a matter of fact, however, the oblique muscles are 



