422 



ANATOMY FOR NURSES 



[Chap. XX 



longer than those of the lower. The upper lid is attached to a 

 small muscle wliich is called the elevator of the upper lid (levator 

 palpebraB superioris), and arranged as a sphincter around both lids 

 is the orbicularis palpebrarum muscle, which closes the eyelids, 

 and is the direct antagonist of the elevator of the upper lid. 



The slit between the e*dges of the lids is called the palpebral 

 fissure. It is the size of this fissure which causes the appearance 

 of large and small eyes, as the size of the lobe itself varies but 

 little. The outer angle of this fissure is called the external can- 

 thus ; the inner angle, the internal canthus. 



The eyelids are obviously provided for the profection of the 

 eye; movable shades which by their closure exclude light, par- 

 ticles of dust, and other injurious substances. 



Tarsal glands (Meibomian glands). — Embedded in the tarsal 

 cartilage of each eyelid is a row of elongated sebaceous glands, 



— the tarsal ^ glands, — 

 the ducts of which open 

 on the edge of the eyelid. 

 The secretion of these 

 glands is provided to 

 prevent adliesion of the 

 eyelids. 



Lacrimal apparatus. — 

 This apparatus consists 

 of : (1) the lacrimal gland, 

 (2) canaliculi, (3) lacrimal 

 sac, and (4) nasal duct. 

 The lacrimal gland is a 

 compound gland, closely 

 resembling the salivary 

 glands in structure, and 

 is lodged in a depres- 

 sion at the upper and 

 outer angle of the orbit. It consists of two portions, an upper por- 

 tion about the size and shape of an almond, and a lower portion 

 consisting of a group of small glands arranged in a row. These 

 two portions are only partially separated by a fibrous septum. 



' By everting the eyelids, these glands may be seen through the conjunctiva 

 lying in parallel rows. 



Fig. 197. — The Lackimal Apparatus. 

 (Note that preference is given to the spelling 

 "lacrimal" as found in text, instead of "lachry- 

 mal" as found on illustration.) 



