88 DISSECTION OF THE EYE. 



through the conjunctiva along the line of the fornix 

 conjunctivae of the upper lid. The lachrymal gland 

 will be exposed lying on the upper and outer surface 

 of the eyeball, between it and the tendinous margin 

 of the orbit. Its ducts open upon the eyeball along 

 the fornix conjunctivae. 



MUSCLES OF THE EYEBALL. 



Remove the skin from the head. To expose the 

 orbital cavity remove the zygomatic arch by sawing 

 through it at its two ends and dissecting it off from 

 the underlying parts. Next dissect azvay the imiscu- 

 lar mass lying beneath the zygoma and on the side of 

 the skull ; in doing this it will be necessary to cut 

 through and remove the coronoid process oj the man- 

 dible, tising the bone forceps. The eyeball zvith its cone- 

 shaped mass of muscles r turning backzvard from it will 

 noiv be exposed ; all other tissues, muscle, fat, etc., must 

 be dissected azvay as carefully as possible. 



Six eye-muscles are usually described, namely, 

 the internal and external rectus, the superior and in- 

 ferior rectus, and the superior and inferior oblique. 

 The dog has in addition a representative of the large 

 retractor bulbi lying beneath the six muscles men- 

 tioned. No special directions can be given for dis- 

 sectinofout these various muscles. The student should 

 read over first the descriptions of all of them, and then 

 dissect as neatly as possible. None of the muscles 

 will be difficult to expose except the superior oblique, 

 which is very liable to be injured or overlooked ; the 

 upper and inner angle of the orbit, therefore, where its 

 tendon is reflected to the eyeball must be dissected 

 with particular care. 



