DPISSECTION..OF THE EYE, 89 
rt. The External Rectus Muscle lies on the outer 
surface of the eyeball; it arises from the bony portion 
of the orbit round the optic foramen, and is inserted 
by a flat tendon into the outer surface of the eyeball 
beneath the conjunctiva. 
2. The Inferior Rectus Muscle lies along the lower 
surface of the eyeball, and has the same general inser- 
tion and origin as the internal rectus, arising also 
from the bone round the optic foramen where the op- 
tic nerve enters the orbit. Its fibres do not lie exactly 
along the vertical meridian of the eyeball, so that its 
contraction will not rotate the eyeball directly down- 
ward. 
3. The Superior Rectus Muscle lies along the upper 
surface of the eyeball; it arises also from the bone 
round the optic foramen, and is inserted into the eye- 
ball on its upper surface. Owing to the direction of 
its fibres its pull will not rotate the eyeball directly up- 
wards. Along the inner edge of this muscle a muscular 
slip may be seen, passing to the inner and upper angle 
of the orbit ; this slip forms part of the levator palpe- 
bree superioris, not one of the muscles of the eyeball. 
4. The Internal Rectus Muscle lies along the inner 
side of the eyeball. It arises from the bone round 
the optic foramen, and passes forward to be inserted 
into the inner aspect of the eyeball. 
5. The Inferior Oblique Muscle will be found along 
the lower and outer side of the front of the eyeball. 
Its fibres arise from the front portion of the floor of 
the orbit, from the orbital portion of the maxillary 
bone, and passing outward obliquely round the eye- 
ball are inserted over the tendon of the external rectus 
muscle. 
6. The Superior Oblique Muscle. The muscular 
