CHAPTER XL 



VISION. 

 I. DISSECTION OF THE EYE. 



1. Appendages. (a) Examine the specimen before you, tracing 

 out the ocular and palpebral conjunctiva, noting the plica semi- 

 lunaris and the caruncula. How do the latter compare in relative 

 size with the human structures ? Locate and describe the puncta 

 lachrymalia and the openings of the lachrymal ducts. How many 

 are there? Is your specimen a right or left eye? 



(b) Observe carefully the appendages, locating the tarsal carti- 

 lages, Meibomian, sebaceous, and lachrymal glands. Observe the 

 recti and oblique muscles and their actions on the eyeball. Ob- 

 serve the entrance of the optic nerve. 



2. By pinning down the flaps of the conjunctiva, fix the eyeball 

 to the board, the cornea downward. Then dissect out the four 

 recti and two oblique muscles, observing the capsule of Tenon. 



Without injuring important vessels and nerves, remove the 

 heavy retractor muscle. Locate and describe the vence vorticosce. 

 How many are there? Find the anterior ciliary arteries. How 

 many are there ? What structures do they supply ? Find the two 

 long ciliary arteries, the short posterior ciliary arteries, and the 

 ciliary nerves. 



3. Eyeball. (a) Fix the eyeball to the board, cornea up, pin- 

 ning down the dissected muscles as guys. After having observed 

 the cornea remove it with heavy scissors, near the corneo-scleral 

 margin. 



(fy Through the opening thus made, examine the iris. Where 

 is the posterior chamber ? 



(r) Holding the margin of the cornea with strong forceps, dissect 



