VISCERAL ANATOMY. 1 65 



cornea, pupil and iris (anterior chamber), is alkaline in reaction, 

 consisting of water with -^q solids. 



The Vitreous fills up the space inside the retina and lens. It 

 consists of gelatinous tissue. 



The crystalline lens is ^-^ by -^^ inches, lies behind the pupil 

 and in front of the vitreous. It is a double convex lens of con- 

 centric layers, with an external capsule. 



MUSCLES OF THE EYELID. 



Oj'bicularis palpebraru77i. 



Origin. — Lachrymal tubercle. 



Insertion. — Skin of both eyelids. 



Action. — vSphincter of lids. 



Levator palpebrcE superior is externus. 



Origin. — External surface of frontal near supra-orbital foramen. 



Insertion. — Into orbicularis. 



Action. — Wrinkles skin of upper lid. 



Levator palpebral superioris internus. 



Origifi. — Superior border of optic foramen. 



Insertion. — Inner surface of upper lid and tarsal cartilage. 



Action. — Raises upper lid. 



Nerve Supply. 



The latter by motor oculi, the others by facial. 



MUSCLES OF GLOBE. 



Retractor oculi. 



Origin. — Optic foramen. 



Insertion. — Outer and back part of sclera. 



Superior. i7iferior, external and internal recti. 



Origi7i. — Margin of optic foramen. 



Insertion. — Above, below, outside and inside sclera. 



Superior oblique. 



Origin. — Optic foramen, passes to internal wall of orbit through 

 a cartilaginous loop. 



Insertion. — Into sclera, between superior and external recti. 



Infeiior oblique. 



Origin. — Lachrymal fossa. 



Insei'tion. — Under sclera. 



Action. — The superior rectus turns the globe upward, the infer- 

 ior down, the external out, the i7iternal in, the superior oblique 



