420 
MUSCLES OF THE EYE. 
more is necessary than to close the upper lid—not forcibly, 
however; next to make pressure upon its upper part with a 
pencil, bodkin, knitting-needle, or other hard body of small 
diameter; and then, taking hold of the eyelashes, to draw 
the lower edge of the lid forwards and upwards. By a dex¬ 
terous movement of this kind, the lid may be everted without 
any pain, a little temporary discomfort being all that the dis¬ 
placement occasions; its lining membrane is then exposed, 
and any offending particle may be readily removed. 
538. The globe of the eye is moved by six muscles, which 
are lodged within the bony cavity or orbit, hollowed-out in the 
skull. All these muscles, except one, originate at the back of 
h e the orbit, and are inserted 
into the sclerotic coat, near its 
front, by broad thin tendons. 
Four of them are termed recti 
or straight muscles. One of 
these, the superior rectus (e, fig. 
209), is inserted at the upper 
part of the eye, and conse¬ 
quently by its contraction rolls 
the globe upwards; another, 
d, the inferior rectus , pro¬ 
duces a corresponding move¬ 
ment downwards. A third, the 
internal rectus (which could 
not be shown in this figure), 
rolls the globe inwards, or 
oblique ; h, superior oblique ; i, elevator towards the nose j w hil st a 
of the upper lid; k, lachrymal gland. p ji , i , /±_i 
tourth, the external rectus (the 
cut extremity of which is seen at/), turns it outwards. Besides 
these, there is a remarkable muscle, h, the superior oblique, 
which originates at the back of the orbit, comes forwards to 
the front, where its tendon passes through a pulley, and then 
turns backwards to be inserted into the sclerotic coat, at a point 
considerably behind the pulley. The sixth muscle, g , termed 
the inferior oblique, does not arise, like the rest, from the 
back of the orbit, but from its lower border. The action of 
the two oblique muscles (which act in antagonism the one to 
the other) appears to be to rotate the eyeball upon its axis ; 
as is done when the eyes are kept steadily fixed upon any 
Orbit. 
Showing the globe of the eye and its ap¬ 
pendages ; a, cornea; b, sclerotic ; c, optic 
nerve; d, inferior rectus muscle; ^supe¬ 
rior rectus ; /, cut extremity of the ex¬ 
ternal rectus; g, end of the inferior 
