CHAPTER III 



DISEASES OF THE LIDS 



From without inward the Hds are composed of skin, a 

 loose areolar tissue, muscle, the tarsus, and conjunctiva. 



The skin is freely movable because of the loose tissue 

 beneath it. It is continuous with the skin of the fore- 

 head, and blends with the conjunctiva at the margin. 

 At this point is a growth of stiff hairs — the lashes — 

 which arise from the margin of both lids usually, though 

 the lower lid of the dog and pig present no distinct lower 

 lashes. 



The tarsus is the framework, and affords the lid firm- 

 ness. The upper tarsus is larger than the lower. It is 

 not cartilage, but it is composed of dense fibrous tissue. 

 The tarsi are connected by the tarsal ligaments to the 

 lateral walls of the orbit and to each other by the pal- 

 pebral ligaments. It contains the meibomian glands, 

 which are about forty in number. These glands are 

 arranged in parallel rows, and they have their exit 

 through small ducts which open at the margin of the 

 lids, posterior to the roots of the lashes. The muscle- 

 fibers are those of the orbicularis and, at the upper 

 portion, the levator palpebrarum. The fibers of these 



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