VISCERAL ANATOMY. 165 



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

 consisting of water with -$ solids. 



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

 consists of gelatinous tissue. 



The crystalline lens is T 5 ^ by T % 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. 



Orbicularis palpebrarum. 

 Origin. Lachrymal tubercle. 

 Insertion. Skin of both eyelids. 

 Action. Sphincter of lids. 

 Levator palpebrce superioris externus. 



Origin. External surface of frontal near supra-orbital fora- 

 men. 



Insertion. Into orbicularis. 

 Action. Wrinkles skin of upper lid. 

 Levator palpebrcz superioris internus. 

 Origin. 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, inferior, external and internal recti. 



Origin. 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. 



Inferior oblique. 



Origin. Lachrymal fossa. 



Insertion. Under sclera. 



Action. The superior rectus turns the globe upward, the 

 inferior down, the external out, the internal in, the superior oblique 



